the moroccan isbn agency isbn 978-9920-35-173-7 of earth sciences jaume almera, barcelona spain...

The Moroccan ISBN Agency ISBN 978-9920-35-173-7

Abstract Book of the 2nd General Assembly for the African Seismological Commission

from 23th until 27th of April 2018 Al-Hoceima, Morocco

Edited by: Mourabit, T., El Talibi, H., El Moussaoui, S. & El kharki, O.

2018

Al Hoceima African Seismological Commission

Editors:

Prof. Taoufik Mourabit Dean Faculty of Sciences and Techniques of Al-Hoceima University of Mohammed Premier, Morocco Email: [email protected]

Prof. Hajar El Talibi Departement of Earth Sciences Faculty of Sciences and Techniques of Al-Hoceima University of Mohammed Premier, Morocco Email: [email protected]

Dr. Said El Moussaoui Department of Earth Sciences Faculty of Sciences and Techniques of Tangier University of Abdelmalek Essaadi, Morocco Email: [email protected]

Prof. Omar El Kharki Department of Earth Sciences Faculty of Sciences and Techniques of Tangier University of Abdelmalek Essaadi, Morocco Email: [email protected] @gmail.com

Coyrights:

© African Seismological Commission, 2018 © Faculty of Sciences and Techniques of Al Hoceima, 2018 All rights reserved.

Legal deposit: 2018MO0824 The Moroccan ISBN Agency ISBN 978-9920-35-173-7

mailto:[email protected]




2nd General Assembly for the African Seismological Commission, Al Hoceima 2018

i

Preface

It is a great pleasure to welcome you at the 2nd General Assembly for the African Seismological Commission (2AfSC2018), held in AL Hoceima, Morocco (23-27 April 2018). This volume includes the 135 abstracts accepted for oral (74) and poster (61) presentations. These were dispatched within 8 sessions covering the majority of seismological topics. All abstracts have been reviewed by the 30 co-chairs of the sessions. In addition, plenary conferences have been organized by researchers who have long devoted themselves to geodynamic and geophysical studies in Africa.

This Abstract volume, which provides an excellent overview of current research trends in seismology, is a reference platform for researchers interested in seismological studies within Africa to promote multi-sectoral and collaborative scientific projects ranging from seismic monitoring, seismotectonics and, seismic hazard to education and outreach.

I would like to express my deep gratitude to the members of the Organizing committee for dedicating so much of their time to the organization of the conference. On behalf of the Organizing Committee, I wish to thank warmly the African Seismological Commission (AfSC) and its Executive Committee for putting their trust in the Moroccan community of seismologists.

Collectively, we are all very grateful to : International Association of Seismology and Physics of the Earth's Interior (IASPEI), Kinemetrics, International Union of Geodesy and Geophysics (IUGG), and International Seismological Center (ISC).

We appreciate very much the support of Moroccan academic institutions, Université Mohamed Premier (UMP)”, the “Centre National de la Recherche Scientifique et Technique (CNRST), the Scientific Institute (IS) of Mohamed V university, the local authorities and representatives for the crucial help and to all sponsors that have kindly provided financial and logistical support in a difficult economic period.

Taoufik MOURABIT Faculty of Sciences and Techniques of Al Hoceima

General Chair of 2nd General Assembly for the African Seismological Commission

.


ii

Contents

Preface .............................................................................................................................................................. i

Contents.......................................................................................................................................................... ii

Steering Committee ................................................................................................................................. xvii

Scientific Committee ............................................................................................................................. xviii

Program Overview ...................................................................................................................................... xx

Detailed scientific program and index of abstracts ..........................................................................xxi

Program Schedule ................................................................................................................................. xxxiv

Abstracts ................................................................................................................................................ xxxvii

Alphabetical Index of Presenting Authors .......................................................................................... 136


iii

Steering Committee

Pr. Taoufik MOURABIT Dean of the Faculty of Sciences and Techniques of Al-Hoceima University of Mohammed Premier, Morocco Email: [email protected] Pr. Mimoun CHOURAK Department of Mecanics and applied mathematics University of Mohammed Premier, Oujda, Morocco Email: [email protected] Pr. Hajar EL TALIBI Departement of Earth Sciences Faculty of Sciences and Techniques of Al-Hoceima Email: [email protected] Pr. Najat Moradi Vice-Dean of Educational Affairs Faculty of Sciences and Techniques of Al-Hoceima Eamail: [email protected] Pr. Hinde CHERKAOUI Head of Departement of Earth Sciences Faculty of Sciences and Techniques of Al-Hoceima Email: [email protected] Pr. Issam ETEBAAI Departement of Earth Sciences Faculty of Sciences and Techniques of Al-Hoceima Email: [email protected] Pr. Abderrahim EL ALLATI Department of Physics Faculty of Sciences and Techniques of Al-Hoceima Email: [email protected] Dr. Said EL MOUSSAOUI Department of Earth Sciences Faculty of Sciences and Techniques of Tangier Email: [email protected]







mailto:[email protected]%C2%A0



iv

Scientific Committee

Atalay AYELE Addis Ababa University · Institute of Geophysics, Space Sciences and Astronomy (IGSSA), Ethiopia Mohamed ABED Saad Dahlab University, Blida, Algeria Bekoa ATEBA Institute of Geol. Mining Research, Cameroon Abdelhakim AYADI Centre of Research of Astronomy, Astrophysics and Astrophysics and Geophysics (Algeria) Alaeddine BELFOUL University Ibn Zohr , Agadir, Morocco Djillali BENOUAR University of Science and Technology Houari Boumediene, Algeria Mourad BEZZEGHOUD School of Sciences and Technology, Universidade de Évora, Portugal Samir BOUAZIZ ENIS-National School of Engineering, University of Sfax ,Tunisia Martin Brandt CGS- Council for Geoscience, South Africa Mimoun CHOURAK ENSA - Mohamed I University of Oujda, Morocco Mohamed EL GABRY NRIAG-National Research Institute of Astronomy and Geophysics, Egypt Nacer JABOUR Centre National pour la Recherche Scientifique et Technique, Morocco Zakaria HAMIMI Banha University, Egypt Assia HARBI Centre of Research of Astronomy, Astrophysics and Geophysics , Algeria

Mimoun HARNAFI Mohammed V University of Rabat, Morocco Awad HASSOUP NRIAG-National Research Institute of Astronomy and Geophysics, Egypt Ahmed HOSNY NRIAG-National Research Institute of Astronomy and Geophysics, Egypt Hesham HUSSIEN NRIAG-National Research Institute of Astronomy and Geophysics, Egypt Jesus GALINDO ZALDIVAR University of Granada, Spain Michelle GROBBELAAR CGS- Council for Geoscience , South Africa Said MAOUCHE Centre of Research of Astronomy, Astrophysics and Geophysics, Algeria Mustapha MEGHRAOUI EOST - Université of Strasbourg, France Vunganai MIDZI CGS- Council for Geoscience, South Africa Taoufik MOURABIT FSTH - Mohamed I University of Oujda, Morocco Hatem ODAH NRIAG-National Research Institute of Astronomy and Geophysics, Egypt Antonella PERESAN OGS- National Institute of Oceanography and Experimental Geophysics, Italy Mohammed ROGUI ESTS- Sale, Morocco Abdelhamid ROSSI FSTT - AbdelmalekEssaadi University of Tangier, Morocco


v

Youssef TIMOULALI Institut Scientifique - University Mohamed V Rabat, Morocco Antonio VILLASENOR Institute of Earth Sciences Jaume Almera, Barcelona Spain Abdelkrim YELLES CHAOUCH CRAAG - Centre of Research of Astronomy, Astrophysics and Geophysics, Algeria Hakim Boulaassal FSTT – Abdelmalek Essaadi University of Tangier, Morocco Khadija Aboumaria FSTT – Abdelmalek Essaadi University of Tangier, Morocco Omar El kharki FSTT – Abdelmalek Essaadi University of Tangier, Morocco Raymond Durrheim School of Geosciences, University of the Witwatersrand Johannesburg, South Africa Ahmed Ksentini National Engineers School of Tunis, Tunisia Abdelilah Tahayt Mohammed V University of Rabat, Morocco

Robert Reilinger Massachusetts Institute of Technology, USA Philippe Vernant Geoscience Montpellier, France Nadia Mhammdi Mohammed V University of Rabat, Morocco Georges Mavonga Goma Volcanic Observatory, Democratic Republic of Congo Damien Delvaux Royal Museum for Central Africa, Belgium Paulina Amponsah Ghana Atomic Energy Commission, Ghana Magda Roos CGS- Council for Geoscience, South Africa Benaissa Tadili Mohammed V University of Rabat, Morocco Lahsen Ait-Brahim Mohammed V University of Rabat, Morocco Najla Romdane University of Tunis El Manar, Tunisia Fabio Romanelli University of Trieste, Italy


vi

Program Overview

Monday 23 April 2018 08h30 Registration 09h00-10h00 Opening speechs 10h00-10h40 Coffee Break 10h40-12h00 Plenary session 12h00-13h00 Lunch Break 13h00-14h00 Shuttles from Hotel to FSTH (1hour)

14h00-16h00 S01: Active Tectonics, Paleoseismology and Historical Seismicity (Room A) S02 : Seismic source/Induced seismicity (Room B)

16h00- 16h40 Coffee Break/poster session

16h40- 18h00 S01: Active Tectonics, Paleoseismology and Historical Seismicity (Room A) S02 : Seismic source/Induced seismicity (Room B)

18h30- 19h30 UNESCO - IGCP-659 Business and kickoff Meeting

Tuesday 24 April 2018

08h40-10h00 S03: Ground motion and site effects (Room A) S04 : Tsunami hazard : data collection and modelling (Room B)

10h00-10h40 Coffee Break/poster session

10h40-12h00 S03: Ground motion and site effects (Room A) S04 : Tsunami hazard : data collection and modelling (Room B)

12h00-14h00 Lunch Break

14h00-16h00 S05 : Earth structures in Africa/The East African Rift System (Room A) S06 : GIS and Risk Scenario (Room B)

16h00- 16h40 Coffee Break/poster session 16h00- 18h00 AFSC Business meeting 20h30 Conference dinner

Wednesday 25 April 2018

08h40-10h00 S07: Earthquake Hazard Assessment (Room A) S08 : Geodynamics,GPS, InSAR and remote sensing (Room B)

10h00-10h40 Coffee Break/poster session


12h00-14h00 Lunch Break


16h00- 16h40 Coffee Break/poster session 16h40- 18h00 S08 : Geodynamics,GPS, InSAR and remote sensing (Room B)

18h30- 19h30 General Discussion and Recommendations (Cloture): The future of AfSC and the Earthquake Data Centre for Africa

Thursday 26 April 2018 09h00-12h00 Practical Training Courses 1: Seismotectonics (Room A) 12h00-14h00 Lunch Break 14h00-18h00 Practical Training Courses 1: Seismotectonics (Room A)

Friday 27 April 2018 09h00-12h00 Practical Training Courses 2: Radar interferometry and its applications: 12h00-14h00 Lunch Break 14h00-18h00 Practical Training Courses 2: Radar interferometry and its applications:


vii

Detailed scientific program and index of abstracts

PLENARY SESSION

C.01: EARTHQUAKES IN AFRICA: THE SEISMOTECTONIC AND SEISMIC HAZARD PERSPECTIVES ........................................................................................................... 1

Meghraoui Mustapha (Monday 23 April 2018: 10h40 – 11h10)

C.02: GLOBAL POSITIONING SYSTEM (GPS) CONTRIBUTIONS TO ACTIVE TECTONICS IN AND BORDERING AFRICA ...................................................................... 2

Reilinger Robert, King Robert, Floyd Michael et al,. (Monday 23 April 2018: 11h10 – 11h40)

C.03: Al Hoceima, The light house of the southern Bank of Western Mediterranean ...................

Ben Sari Driss,. (Monday 23 April 2018: 11h40 – 12h10)

S.01: ACTIVE TECTONICS, PALEOSEISMOLOGY AND HISTORICAL SEISMICITY

S.01O01: RECENT SEISMICITY AND EARTHQUAKE RISK IN ETHIOPIAN CITIES ............ 3

Atalay Ayele (Monday 23 April 2018: 14h00)

S.01O02: ACTIVE TECTONICS OF PERU: HETEROGENEOUS INTERSEISMIC COUPLING ALONG THE NAZCA MEGATHRUST, RIGID MOTION OF THE PERUVIAN SLIVER, AND SUBANDEAN SHORTENING ACCOMMODATION ................................................................................................................... 4

Chlieh Mohamed, Villegas Lanza Juan Carlos, Cavalié Olivier et al,. (Monday 23 April 2018: 14h20)

S.01O03: PRESENT-DAY SEISMOTECTONICS BENEATH THE RIF-ATLAS AREA, MOROCCO, FROM EARTHQUAKE FOCAL MECHANISM DATA ............................ 5

El Moudnib Lahcen (Monday 23 April 2018: 14h40)

S.01O04: GEOLOGY, TECTONIC AND DEEP PROCESS IN THE HOGGAR SWELL (ALGERIA) ...................................................................................................................................... 6

Abdelhakim Ayadi, Meghraoui Mustapha, Said Maouche (Monday 23 April 2018: 15h00)

S.01O05: USE OF EARTHQUAKE LOCATIONS TO IDENTIFY SEISMOGENIC STRUCTURES IN THE WITWATERSRAND BASIN, SOUTH AFRICA .................... 7

Myendeki Sinovuyo (Monday 23 April 2018: 15h20)

S.01O06: VERY RECENT SEABOTTOM DEFORMATION IN THE AREA AFFECTED BY THE 2016-2017 SEISMIC CRISIS IN THE ALBORAN SEA (WESTERN MEDITERRANEAN) .................................................................................................................... 8

Galindo-Zaldivar Jesus , Ercilla Gemma, Estrada Ferran et al,. (Monday 23 April 2018: 15h40)


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S.01O07: AL HOCEIMA NORTHERN MOROCCO 1994, 2004 AND 2016 SEISMIC SEQUENCES ................................................................................................................................... 9

Nacer Jabour (Monday 23 April 2018: 16h40)

S.01O08: THE ACTIVE FAULTS OF THE MITIDJA BASIN (NORTH CENTRAL ALGERIA): WHAT DOES THE SEISMIC HISTORY OF THE REGION TELL US? .................................. 10

Maouche Said, Harbi Assia (Monday 23 April 2018: 17h00)

S.01O09: THE SEISMITES OF THE PLEISTOCENE FORMATIONS IN THE NORTH-EAST OF RABAT AS AN INDICATOR OF PREHISTORIC EARTHQUAKES AND PROBABLE PRECURSOR OF THE LISBON EARTHQUAKE OF 1755 AD............................ 11

Lambarki Drissi Ibtissam, Aberkane M'hamed (Monday 23 April 2018: 17h20)

S.01O10: REVIEW IN SEISMOTECTONIC SETTING OF GULF OF AQABA WITH RESPECT TO THE 27 JUNE 2015 AND 16 MAY 2016 AQABA EARTHQUAKE SWARMS ........................................................................................................................................ 12

Abdel-Aal Abdel-Aziz, Mostafa Shaimaa (Monday 23 April 2018: 17h40)

S.01P01: SEISMICITY AND STRESS FIELD VARIATIONS IN RIF REGION & ALBORAN SEA FROM MAJOR SEISMIC CRISIS : 1960-2016. ...................................... 13

Dahaoui Mohamed, Abdelouafi Abdellah, El Mahsani Abderrahman et al,. (Monday 23 April 2018: Poster session)

S.01P02: LA MORPHO-STRUCTURE DES FORMATIONS NEOGENE ET PLIO-QUATERNAIRES DU RIF ORIENTAL (MAROC) ............................................................ 14

Makkaoui Mohamed, Azzouz Omar (Monday 23 April 2018: Poster session)

S.01P03: UPDATED SEISMICITY OF BOTSWANA FOR THE PERIOD 1950?2017 ................. 15

Kwadiba Tarzan, Ntibinyane Onkgopotse, Mpuang Admore et al., (Monday 23 April 2018: Poster session)

S.01P04: SOFT-SEDIMENT DEFORMATION STRUCTURES INDUCED BY EARTHQUAKES (SEISMITES) IN QUATERNARY DEPOSITS (WESTERN ORAN ,ALGERIA) ........................................................................................................................ 16

Guessoum Nabila, Benhammouche Azzeddine, Bouhadad Youcef (Monday 23 April 2018: Poster session)

S.01P05: GEOMORPHIC, STRATIGRAPHY AND NEOTECTONICS IN THE HODNA BASIN (ALGERIA): CASE STUDY OF THE CHOTT EL HAMMAM STRUCTURE ................................................................................................................................. 17

Ahmed Rezouk, René Guiraud, Bouhadad Youcef et al., (Monday 23 April 2018: Poster session)

S.01P06: THE ACHAKKAR QUATERNARY FM. SEISMITES (NORTHERN ATLANTIC COAST, MOROCCO): ARE THEY TRIGGERED BY RECENT SEISMOTECTONICS ACTIVITY ............................................................................................ 18

Benamri Sofia, Aboumaria Khadija, Aberkan M'hamed et al., (Monday 23 April 2018: Poster session)

S.01P07: SEISMOTECTONICS MAP OF NORTHERN EGYPT ..................................................... 19

Salama Asem, Meghraoui Mustapha, El Gabry Mohamed et al., (Monday 23 April 2018: Poster session)

S.01P08: THE SEISMES OF THE SÉTIF REGION, READING AND INTERPRETATION .................................................................................................................... 20

Djenba Samir (Monday 23 April 2018: Poster session)


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S.01P09: SEISMICITY AND SEISMOTECTONIC OF THE AREA OF ALGAVRE (PORTUGAL) ............................................................................................................................... 21

Dib Assia, Bezzeghoud Mourad, Abdelhakim Ayadi et al., (Monday 23 April 2018: Poster session)

S.01P10: ACTIVE TECTONIC IN MEDITERANEAN COAST: NEW INSIGHTS FOR THE ARZEW SALINES, NORTHWEST ALGERIA .......................................................... 22

Benbakhti Imene Meriem, Maouche Said, Belhai Djelloul et al., (Monday 23 April 2018: Poster session)

S.01P11: L'UTILISATION D'UN IMEL POUR L'ÉTUDE LE MOUVEMENT DE LA FAILLE DE TROUGOUT - NORD EST DU RIF) MAROC) - ......................................... 23

Morad Taher, Taoufik Mourabit (Monday 23 April 2018: Poster session)

S.02: SEISMIC SOURCE/INDUCED SEISMICITY

S.02O01: ASWAN INDUCED SEISMICITY ........................................................................................ 24

Hassoup Awad (Monday 23 April 2018: 14h00)

S.02O02: EARTHQUAKE LABORATORIES IN DEEP SOUTH AFRICAN MINES ................. 25

Durrheim Raymond, Andriamiranto Raveloson, Ogasawara Hiroshi et al., (Monday 23 April 2018: 14h20)

S.02O03: SEISMIC REFRACTION AND AMBIENT NOISE H/V SURVEYS TO INVESTIGATE AND REBUILD AN OLD BRIDGE, ACROSS GHIS RIVER LOCATED IN THE SEISMIC AREA OF AL HOCEIMA, NOTH MOROCCO .......... 26

El Ouai Driss, Tadili Ben Aissa, Tadili Mehdi (Monday 23 April 2018: 14h40)

S.02O04: SEISMIC HAZARD AND NEW SEISMOGENIC ZONING IN THE STRAIT OF GIBRALTAR ........................................................................................................................... 27

Abderrahman Elmahsani, Ait Brahim Lahcen, Tadili Benaissa et al., (Monday 23 April 2018: 15h00)

S.02O04: THE 2016 MIHOUB (NORTH-CENTRAL ALGERIA) EARTHQUAKE SEQUENCE: SEISMOLOGICAL AND TECTONIC ASPECTS ...................................... 28

Khelif Mohamed Fadhlallah, Yelles-Chaouche Abdekrim, Benaissa Zahia (Monday 23 April 2018: 15h20)

S.02O06: ASSESSMENT OF TEMPORAL VARIATION AND SPATIAL VARIATION OF RECURRENCE PARAMETERS IN THE GOLD MINING REGIONS OF SOUTH AFRICA ..........................................................................................................................29

Zulu Brian Sibonelo, Midzi Vunganai, Manzunzu Brassnavy et al., (Monday 23 April 2018: 15h40)

S.02O07: REASSESSING THE RUPTURE PROCESS OF THE 2003 BOUMERDES-ZEMMOURI EARTHQUAKE (MW 6.8, NORTHERN ALGERIA) USING TELESEISMIC, STRONG MOTION, INSAR, GPS, AND COASTAL UPLIFT DATA ............................................................................................................................................... 30

Beldjoudi Hamoud, Delouis Bertrand, Yelles Chaouche Abdelkrim et al., (Monday 23 April 2018: 16h40)

S.02O08: SPATIAL DISTRIBUTION OF ATTENUATION IN NORTHERN MOROCCO AND THEIR INTERPRETATION .................................................................. 31

Boulanouar Abderrahim, Harnafi Mimoun, Dobrynina Anna et al., (Monday 23 April 2018: 17h00)


x

S.02P01: THE 2018, 15 JANUARY EARTHQUAKE, ARRAIOLOS (PORTUGAL, M=4.9): RESULTS FROM THE BROADBAND SEISMIC NETWORK DATA AND MACOSEISMIC SURVEY. ............................................................................................. 32

Caldeira Bento, Araújo A. Alexandre, Borges José et al., (Monday 23 April 2018: Poster session)

S.02P02: SÉQUENCE SISMIQUE DE LA RÉGION D'AÏN AZEL (SUD DE SÉTIF ) JANVIER-MAI 2015. ................................................................................................................... 33

Chami Adel, Yelles-Chaouche Abdelkrim, Benaissa Zahia et la., (Monday 23 April 2018: Poster session)

S.02P03: BACKGROUND NOISE OF THE ALDEIA DA SERRA REGION, PORTUGAL ? FROM A TEMPORARY BROAD BAND NETWORK .......................... 34

Wachilala Piedade, Borges José, Caldeira Bento (Monday 23 April 2018: Poster session)

S.02P04: SOURCE PARAMETERS OF THE MAIN SEISMIC EVENTS IN THE NORTHEAST REGION OF ALGERIA .................................................................................. 35

Abacha Issam, Boulahia Oualid, Yelles-Chaouche Abdelkarim et al., (Monday 23 April 2018: Poster session)

S.02P05: A STUDY ON THE RELATION BETWEEN RECENT INDUCED SEISMICITY AND WATER LEVEL IN THE NORTHWESTERN PART OF NASSER LAKE, ASWAN- EGYPT .......................................................................................... 36

Omar Khaled, Dahy Sayed, Al Amin Ezat (Monday 23 April 2018: Poster session)

S.02P06: TRACKING SPATIOTEMPORAL VARIATIONS OF GROUND DEFORMATION AND SOURCE PARAMETERS ALONG SLOW CONVERGENT PLATE BOUNDARIES CASE OF FIGURE: NORTHERN MOROCCO (WESTERNMOST MEDITERRANEAN) ....................................................37

Bouskri Ghizlane, Ammar Abdellah, Timoulali Youssef et al., (Monday 23 April 2018: Poster session)

S.02P07: SEISMOTECTONIC MAP OF EGYPT ................................................................................. 38

Badreldin Hazem (Monday 23 April 2018: Poster session)

S.03: GROUND MOTION AND SITE EFFECTS

S.03O01: STRUCTURE OF MITIDJA BASIN FROM HVSR ........................................................... 39

Fontiela Joao, Borges José, Ouyed Merzouk, Bezzeghoud Mourad et al., (Tuesday 24 April 2018: 08h40)

S.03O02: TRAIN INDUCED WAVES PROPAGATION IN LAYERED SOIL ............................. 40

Mohammed Touati, Nezha Lamdouar, Ali Essahlaoui (Tuesday 24 April 2018: 09h00)

S.03O03: SEISMIC GROUND MOTION AND LAND USE PLANNING FOR THE GREATER ACCRA METROPOLITAN AREA, SOUTHEASTERN GHANA ............. 41

Amponsah Paulina, Franco Vaccari, Panza Guliano (Tuesday 24 April 2018: 09h20)

S.03O04: ESTIMATION OF SHEAR WAVE VELOCITY PROFILES USING MICROTREMOR ARRAY EXPLORATIONS IN ISMAILIA CITY, EGYPT .............. 42

Maklad Mohamed, Elgabry Mohamed, Yokoi Toshiaki et al., (Tuesday 24 April 2018: 09h40)


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S.03O05: LOCAL SITE EFFECTS STUDY BASED ON THE ORKNEY EARTHQUAKE OF 5 AUGUST 2014 ..................................................................................................................... 43

Mulabisana Thifhelimbilu, Midzi Vunganai (Tuesday 24 April 2018: 10h40)

S.03O06: FORMING OF LANDSLIDES AS A CONSEQUENCE OF SEISMIC ACTIVITY IN THE AREA OF BOSNIA AND HERZEGOVINA.................................... 44

Smailhodzic Hrustem (Tuesday 24 April 2018: 11h00)

S.03O07: SITE-EFFECTS INVESTIGATION IN THE URBAN AREA OF NADOR TOWN (N-E MOROCCO), USING THE H/V TECHNIQUE ....................................... 45

Chaaraoui Aboubakr, Chourak Mimoun, Peláez Jose (Tuesday 24 April 2018: 11h20)

S.03O08: STATIC CORRECTION FOR SEISMIC DATA ACQUIRED FROM BOUJDOUR AND TARFAYA-LAAYOUNE AREAS (SOUTH OF MOROCCO) ................................................................................................................................. 46

Ayad Abderrrahim, Bakkali Saad (Tuesday 24 April 2018: 11h40)

S.03P01: SITE-EFFECTS INVESTIGATION IN THE CITY OF CHLEF, ALGERIA, USING EARTHQUAKE AND AMBIENT VIBRATION DATA ...................................... 47

Layadi Khalissa (Tuesday 24 April 2018: Poster session)

S.03P02: ATTENUATION OF CODA WAVES IN SOUSS BASIN, MOROCCO ...................... 48

Azguet Roumaissae, Bouskri Ghizlane, Timoulali Youssef et al., (Tuesday 24 April 2018: Poster session)

S.03P03: SOIL AMPLIFICATION FACTORS AT THE SEISMOGRAPHIC NETWORK STATIONS SITES IN MOROCCO FROM SEISMIC AMBIENT NOISE ............................................................................................................................................. 49

El Fellah Younes, Abd El-Aal Abd El-Aziz et al., (Tuesday 24 April 2018: Poster session)

S.04: TSUNAMI HAZARD: DATA COLLECTION AND MODELLING

S.04O01: HOW TIDE VARIATIONS CAN AFFECT THE TSUNAMI IMPACT ON A COASTAL AREA? ........................................................................................................................ 50

El Moussaoui Said, Omira Rachid, El Talibi Hajar et al., (Tuesday 24 April 2018: 08h40)

S.04O02: EVIDENCES OF AN EXTREME MARINE INUNDATION EVENT ON RABAT AREA ATLANTIC COAST (MOROCCO) ............................................................ 51

Benamri Sofia, Aboumaria Khadija et al., (Tuesday 24 April 2018: 09h00)

S.04O03: THE 1790 ORAN LARGE EARTHQUAKE (IO IX-X MKS) AND ITS IMPACT IN THE ALBORAN SEA: MODELING OF TSUNAMI WAVES AND CONSTRAINT OF SEISMIC SOURCE ................................................................................. 52

Meghraoui Mustapha, Kariche Jugurtha, Aini Djamel (Tuesday 24 April 2018: 09h20)

S.04O04: TSUNAMI DEPOSITS AND HAZARD ALONG NORTH COAST OF EGYPT CORRELATE WITH HISTORICAL EARTHQUAKE RECORDS OF EASTERN MEDITERRANEAN ............................................................................................... 53

Salama Asem, Meghraoui Mustapha, El Gabry Mohamed et al., (Tuesday 24 April 2018: 09h40)


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S.04O05: EVIDENCE OF TSUNIMAGENIC SOURCES ALONG THE ALGERIAN MARGIN ........................................................................................................................................ 54

Kherroubi Abdelaziz, Yelles Chaouche Abdelkrim, Beldjoudi Hamoud (Tuesday 24 April 2018: 10h40)

S.04O06: COULD THE DEPOSITS OF HIGH ENERGY ALONG THE IBERIAN AND MOROCCAN COASTS BE RELATED TO TSUNAMIGENIC EARTHQUAKES? ........................................................................................................................ 55

Korchy Hanan, Aberkan M'hamed, Benamri Sofia (Tuesday 24 April 2018: 11h00)

S.04O07: TSUNAMI EVACUATION PLAN FOR TANGIER-MOROCCO BASED ON GIS TOOLS .................................................................................................................................... 56

Benchekroun Sabah (Tuesday 24 April 2018: 11h20)

S.04P01: CARTOGRAPHIE ET SIMULATION DES RISQUES NATURELS DU LITTORAL MAROCAIN : RÉSULTATS PRÉLIMINAIRES ........................................... 57

Fajri Zainab, Aboumaria Khadija, El Talibi Hajar et al., (Tuesday 24 April 2018: Poster session)

S.04P02: EVIDENCES OF AN EXTREME MARINE INUNDATION EVENT ON TANGIER COASTAL PLAIN ( MOROCCAN ATLANTIC COAST) ........................... 58

El Talibi Hajar, El Moussaoui Said, Aboumaria Khadija et al., (Tuesday 24 April 2018: Poster session)

S.04P03: THE PALEOTSUNAMI EVIDENCE AT THE LEVEL OF THE RABTA MARINE TERRACE IN THE JIJEL REGION (EAST ALGERIA) ................................. 59

Benhamouche Azzeddine (Tuesday 24 April 2018: Poster session)

S.05: EARTH STRUCTURES IN AFRICA/THE EAST AFRICAN RIFT SYSTEM

S.05O01: SEISMIC STRUCTURE OF THE SOUTHERN PART OF MADAGASCAR AS REVEALED BY WAVEFORM MODELING ................................................................. 60

Raveloson Andriamiranto, Durrheim Raymond, Rindraharisaona Elisa (Tuesday 24 April 2018: 14h00)

S.05O02: THREE DIMENSIONAL TOMOGRAPHIC IMAGE OF THE TRIPLE JUNCTION AREA, NORTHEAST OF EGYPT .................................................................... 61

Faried Ahmad M., Hosny Ahmed, Farouk Mohamed (Tuesday 24 April 2018: 14h20)

S.05O03: CONTRIBUTION OF THE RECEIVER FUNCTION METHOD IN THE VALIDATION OF THE SEISMIC DISCONTINUITIES MODEL IN TUNISIAN AREA ........................................................................................................................ 62

Rekik Dhouha, Ksentini Ahmed, Abbes Chedly (Tuesday 24 April 2018: 14h40)

S.05O04: THINNING CRUST WITH HIGH VP/VS RATIO BENEATH THE ABOU DABBAB AREA, SOUTHEAST OF EGYPT. ......................................................................... 63

Hosny Ahmed (Tuesday 24 April 2018: 15h00)

S.05O05: INVESTIGATION OF THE 2017 BOTSWANA M6.5 EARTHQUAKE AND ITS AFTERSHOCKS ................................................................................................................... 64

Midzi Vunganai, Saunders Ian, Manzunzu Brassnavy et al., (Tuesday 24 April 2018: 15h20)


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S.05P01: RECENT SEISMICITY (2014- 2017) OF THE OKAVANGO DELTA REGION: CONTRIBUTION OF BOTSWANA'S SEISMIC NETWORK ........................................ 65

Ntibinyane Onkgopotse, Kwadiba Tarzan, Tladi Bruno et al., (Tuesday 24 April 2018: Poster session)

S.05P02: ASSESSING CTBTO'S DATA AND PRODUCTS FOR EARTHQUAKES RELOCATION AND IMPROVEMENT OF VELOCITY MODEL IN SUB-SAHARAN AFRICAN ................................................................................................................. 66

Kadiri Umar, Ezomo Friday, Yakubu Tahir (Tuesday 24 April 2018: Poster session)

S.05P03: ACTIVE INTRABASIN FAULTING IN THE NORTHERN BASIN OF LAKE MALAWI FROM SEISMIC REFLECTION DATA............................................................. 67

Chindandali Patrick R.n. (Tuesday 24 April 2018: Poster session)

S.05P04: PRECISE STUDY OF THE 2009-2010, KARONGA EARTHQUAKE SWARMS ....................................................................................................................................... 68

Marimira Kwangwari, Shumba Blessing, Mphepo Felix (Tuesday 24 April 2018: Poster session)

S.06: GIS AND RISK SCENARIO

S.06O01: SEISMIC EVALUATION OF EXISTING RC BUILDINGS IN AL HOCEIMA AND IMZOUREN USING THE SEISMIC INDEX METHOD ........................................ 69

Cherif Seif Eddine, Chourak Mimoun, Nobuoto Nojima et al., (Tuesday 24 April 2018: 14h00)

S.06O02: EVALUATION OF THE FUNCTIONS OF THE WETLAND COMPLEX BAS LOUKKOS BY GIS AND REMOTE SENSING .................................................................... 70

Fathi Badr-Eddine, Afilal Tribak Abdelghani, Wahbi Meriam (Tuesday 24 April 2018: 14h20)

S.06O03: STUDY OF THE IMPACT OF THE SPATIAL AND TEMPORAL DISTRIBUTION OF URBAN HEAT ISLANDS USING REMOTE SENSING AND GIS TECHNIQUE IN THE REGION OF NADOR (ORIENTAL RIF, MOROCCO) ................................................................................................................................... 71

Tahouri Jad, Sadiki Abdelhamid (Tuesday 24 April 2018: 14h40)

S.06O04: CLIMATE CHANGE EFFECT IN AHWAR ESTUARY AREA IN YEMEN DURING (1985 - 2015) ................................................................................................................ 72

Al-Mahfadi Afrah, Dakki Mohamed (Tuesday 24 April 2018: 15h00)

S.06O05: COASTAL VULNERABILITY MAPPING USING THE ANALYTICAL HIERARCHICAL PROCESS CASE OF AD-DAKHLA IN SOUTHWESTERN MOROCCO .................................................................................................................................... 73

Hakdaoui Sofia, Emran Anas (Tuesday 24 April 2018: 15h20)

S.06O06: MODELING AND SPATIALIZATION OF WATER EROSION ON THE LANDS OF TWO BASINS OF THE WESTERN MOROCCAN RIF. ............................ 74

Ouallali Abdessalam, Moukchane Mohamed, Aassoumi Habiba (Tuesday 24 April 2018: 15h40)

S.06P01: NEOTECTONIC AND SEISMOTECTONIC INVESTIGATION IN SEISMICALLY ACTIVE REGIONS OF TUNISIA: SEISMOGENIC POTENTIALITIES AND SEISMIC HAZARD ASSESSMENT ......................................... 75

Bahrouni Nejib, Merzougui Wissem, Maamri Ridha et al., (Tuesday 24 April 2018: Poster session)


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S.06P02: GIS AND GUIDELINES PAP / RAC FOR MAPPING AND MODELLING OF WATER EROSION RISK PROCESSES IN THE WATERSHED OF OUED ZGANE, (MIDDLE ATLAS MOROCCO)............................................................................. 76

Ousmana Habiba, El Hmaidi Abdellah, El Abassi Mourad et al., (Tuesday 24 April 2018: Poster session)

S.06P03: MODÉLISATION ET SIMULATION 2D DU RISQUE D'INONDATION DANS LA VILLE DE ZAÏO (MAROC NORD-ORIENTAL) ............................................. 77

Naiji Zakariae, Lazzar Ayoub, Oujidi Mostafa et al., (Tuesday 24 April 2018: Poster session)

S.06P04: CARTOGRAPHY OF SEISMIC HAZARD IN THE PLAIN OF KASSERINE (WESTERN TUNISIA) USING MORPHOMETRIC INDEXES-SEMI AUTOMATED APPROACH ..................................................................................................... 78

Chaieb Ali, Rebai Noamen, Bouaziz Samir (Tuesday 24 April 2018: Poster session)

S.06P05: LA CINEMATIQUE D'EVOLUTION DU TRAIT DE COTE DU LITTORAL D'EL JADIDA FACE A LA VULNERABILITE...................................................................... 79

Bourhili Amine, Bendahhou Zourarah, El Khalidi Khalid et al., (Tuesday 24 April 2018: Poster session)

S.07: EARTHQUAKE HAZARD ASSESSMENT

S.07O01: SEISMIC ASSESSMENT OF A CULTURAL HERITAGE STRUCTURE IN CAIRO CONSIDERING THE SCENARIO BASED APPROACH .................................. 80

Hassan Hany, Sayed Mohamed, Romanelli Fabio et al., (Wednesday 25 April 2018: 08h40)

S.07O02: RESEARCHING ENGINEERING CAUSES IN 2003 BOUMERDES-ALGIERS (ALGERIA) EARTHQUAKE DISASTER: A FORENSIC STYLE METHODOLOGY ......................................................................................................................... 81

Benouar Djilali (Wednesday 25 April 2018: 09h00)

S.07O03: APPLICATION OF CRISIS CODE TO ASSESS THE SEISMIC HAZARD IN THE EASTERN RIF OF MOROCCO .................................................................................... 82

El Mahsani Abderahman, Ait Brahim Lahsen, Rfifi Mohamed et al., (Wednesday 25 April 2018: 09h20)

S.07O04: USING GIS TECHNIQUES FOR THE STUDY OF THE EVOLUTION OF EARTHQUAKES IN MOROCCO BETWEEN THE PERIOD FROM 1901 TO 2010 .................................................................................................................................................. 83

Tahouri Ouassim, Dridri Abdallah, Tahouri Jad (Wednesday 25 April 2018: 09h40)

S.07O05: TOWARD PROBABILISTIC SEISMIC HAZARD MODEL SELECTION FOR AFRICA ................................................................................................................................ 84

Ksentini Ahmed, Romdhane Najla (Wednesday 25 April 2018: 10h40)

S.07O06: NEOTECTONICS AND SEISMOTECTONICS OF THE KIVU RIFT BASIN: IMPLICATIONS FOR SEISMIC HAZARD ASSESSMENT ............................................ 85

Delvaux Damien, Fiama Sylvanos B., Ganza Gloire B et al., (Wednesday 25 April 2018: 11h00)

S.07O07: POST-ERUPTIVE SEISMIC ACTIVITY OF MOUNT CAMEROON FOR THE PERIOD 2005-2016 ............................................................................................................ 86

Ateba Bekoa, Mbossi Eddy Ferdinand (Wednesday 25 April 2018: 11h20)


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S.07O08: A FORECASTING MODEL FOR M>5 EARTHQUAKES USING SPATIALLY-SMOOTHED SEISMICITY. APPLICATION FOR THE ALGERIA-MOROCCO REGION. ........................................................................................... 87

Mohamed Hamdache, Jose Pelaez, Karim Yelles-Chaouche (Wednesday 25 April 2018: 11h40)

S.07O09: SEISMIC HAZARD ASSESSMENT OF THE DEMOCRATIC REPUBLIC OF CONGO AND SURROUNDING AREAS BASED ON RECENT COMPILED SEISMIC ZONATION SOURCE MODELS .......................................................................... 88

Mavonga Tuluka Georges, Delvaux Damien, Durrheim Raymond (Wednesday 25 April 2018: 14h00)

S.07O10: THE AL HOCEIMA EARTHQUAKE SEQUENCE OF 1994, 2004 AND 2016: STRESS TRANSFER AND POROELASTICITY IN THE RIF AND ALBORAN SEA REGION ................................................................................................................................. 89

Kariche Jugurtha, Meghraoui Mustapha, Timoulali Youssef (Wednesday 25 April 2018: 14h20)

S.07O11: SEISMICITY RATE INFERRED FROM GEOLOGY MODEL AND IMPLICATION IN PROBABILISTIC SEISMIC HAZARD ASSESSMENT, THE CASE OF GAFSA FAULT IN SOUTHWESTERN TUNISIA ............................... 90

Athmouni Malak, Ksentini Ahmed, Abbes Chedly (Wednesday 25 April 2018: 14h40)

S.07O12: TOWARD A HOMOGENEOUS MOMENT-MAGNITUDE DETERMINATION FOR EARTHQUAKES IN SOUTH AFRICA: ANALYSIS OF UNCERTAINTIES IN MAGNITUDE CONVERSION ............................................... 91

Manzunzu Brassnavy, Brandt Martin, Midzi Vunganai et al., (Wednesday 25 April 2018: 15h00)

S.07P01: AN OVERVIEW OF: THE PROBABILISTIC SEISMIC HAZARD ASSESSMENT FOR SUDAN AND THE KHARTOUM SEISMICITY ..........................92

El Tahir Nada, Midzi Vunganai (Wednesday 25 April 2018: Poster session)

S.07P02: EVALUATION DE L'ALÉA SISMIQUE DE LA RÉGION DE CONSTANTINE (NORD-EST ALGÉRIEN) .......................................................................................................... 93

Hamidatou Mouloud, Mohammdi Yahia, Nassim Hellal (Wednesday 25 April 2018: Poster session)

S.07P03: SISMICITE ET RISQUE SISMIQUE AU MAROC ........................................................... 94

Haou Youssef, Serroukh Mostafa, Ouazani Touhami Abdelouahed et al., (Wednesday 25 April 2018: Poster session)

S.07P04: IDENTIFICATION DES PARAMÈTRES SISMIQUES RELATIFS AU SOL DE LA RÉGION DU GRAND NADOR .................................................................................. 95

Azougay Abdellah, Chaaraoui Aboubakr, Rezqi Halima et al., (Wednesday 25 April 2018: Poster session)

S.07P05: SITE EFFECTS, AMPLIFICATION AND SOIL CHARACTERIZATION OF ALGIERS SEISMIC ZONE ........................................................................................................ 96

Chabane Souhila (Wednesday 25 April 2018: Poster session)

S.07P06: PRELIMINARY STUDY OF SEISMIC HAZARD ALONG THE CAMEROON VOLCANIC LINE ......................................................................................................................... 97

Nana Gaelle Vanessa, Tokam Alain-Pierre (Wednesday 25 April 2018: Poster session)


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S.07P07: STRESS CHANGE AND FAULT INTERACTION FROM A TWO CENTURY-LONG EARTHQUAKE SEQUENCE IN THE CENTRAL TELL ATLAS, ALGERIA ........................................................................................................................ 98

Kariche Jugurtha, Meghraoui Mustapha, Ayadi Abdelhakim et al., (Wednesday 25 April 2018: Poster session)

S.07P08: RAPID EARTHQUAKE DAMAGE ASSESSMENT OF BUILDINGS USING FUZZY LOGIC APPROACH: APPLICATION TO ALGERIAN BUILDINGS ........... 99

Allali Sid Ahmed, Abed Mohamed, Mebarki Ahmed (Wednesday 25 April 2018: Poster session)

S.07P09: EVALUATION DES DOMMAGES STRUCTURAUX POST-SÉISMIQUES PAR LES RÉSEAUX DE NEURONES ................................................................................. 100

Noura Hichem, Abed Mohamed, Mebarki Ahmed (Wednesday 25 April 2018: Poster session)

S.07P10: VULNERABILITY/DAMAGE CURVES FOR MAJOR CITIES IN SOUTH AFRICA ......................................................................................................................................... 101

Pule Tebogo, Fourie Christoffel, Kijko Andrzej et al., (Wednesday 25 April 2018: Poster session)

S.08: GEODYNAMICS, GPS, INSAR AND REMOTE SENSING

S.08O01: MAPPING OF LANDSLIDES BY INTERFEROMETRY RADAR CASE OF LANDSLIDES IN TAOUNATE PROVINCE IN NORTHERN MOROCCO............. 102

Said Benchelha, Hassnaa Chennaoui, Mustapha Hakdaoui et al., (Wednesday 25 April 2018: 08h40)

S.08O02: POTENTIAL FIELDS INTERPRETATION IN THE NW OF ALGERIA: EVIDENCES OF ACTIVE FAULTS AND UNDERGROUND STRUCTURE. .......... 103

Boukerbout Hassina, Abtout Abdeslam, Yelles-Chaouche Abdelkarim et al., (Wednesday 25 April 2018: 09h00)

S.08O03: PLIO-QUATERNARY TECTONIC INVERSION EVIDENCED ALONG THE ALGERIAN MARGIN .............................................................................................................. 104

Yelles Abdelkarim, Aidi Chafik, Beslier Marie-Odile et al., (Wednesday 25 April 2018: 09h20)

S.08O04: AN INITIATION OF A SUBDUCTION ZONE ALONG THE ALGERIAN MARGIN: WHAT DOES THERMOMECHANICAL MODELING SAY?.................. 105

Hamai Lamine, Yelles-Chaouche Abdelkarim, Petit Carole et al., (Wednesday 25 April 2018: 09h40)

S.08O05: ESTIMATION OF VERTICAL MOVEMENTS IN THE RIF MOUNTAINS (MOROCCO) USING PERMANENT GPS MEASUREMENTS, TIDE-ALTIMETRY AND SEISMICITY ........................................................................................... 106

Fatima Ezzahrae Al Makkassi, Tahayt Abdelilah et al., (Wednesday 25 April 2018: 10h40)

S.08O06: NEW CONSTRAINTS ON THE NUBIA-EURASIA PLATE BOUNDARY KINEMATICS FROM GPS MEASUREMENTS IN ALGERIA ..................................... 107

Bougrine Amina, Yelles Karim, Calais Eric et al., (Wednesday 25 April 2018: 11h00)

S.08O07: ACTIVE TRANSFORM FAULTS IN THE GULF OF GUINEA: INSIGHTS FROM GEOPHYSICAL DATA AND IMPLICATIONS FOR THE SEISMIC HAZARD ASSESSMENT......................................................................................................... 108

Meghraoui Mustapha, Amponsah Paulina, Bernard Paul et al., (Wednesday 25 April 2018: 11h20)


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S.08O08: THE REACTIVATION CLUES OF THE EAST-ALGERIAN MARGIN ................... 109

Bouyahiaoui Boualem, Sage Françoise, Abtout Abdeslam et al., (Wednesday 25 April 2018: 11h40)

S.08O09: CURRENT STATE OF UNDERSTANDING OF TECTONICS IN MOROCCO FROM TWO DECADES OF GEODETIC OBSERVATIONS ................. 110

Tahayt Abdelilah, Reilinger Robert, Floyd Michael et al., (Wednesday 25 April 2018: 14h00)

S.08O10: PRESENT-DAY VERTICAL DEFORMATION IN NEW ZELAND FROM TWO DECADES OF GPS DATA ............................................................................................ 111

Fadil Abdelali, Tenzer Robert, Almakkassi Fatimaezzahrae et al., (Wednesday 25 April 2018: 14h20)

S.08O11: FUSION SENTINEL-1 SAR WITH SENTINEL-2 OPTICAL TO EVALUATION AND MONITORING THE DYNAMICS OF TERRITORIES ........... 112

Mahyoub Sulaiman, Rhinane Hassan, El Mehdi Monsour et al., (Wednesday 25 April 2018: 14h40)

S.08012: MULTISOURCE APPROACH FOR MONITORING SPATIAL POSITION AND MOISTURE/DRYNESS SURFACE INFORMATION OF WATER CAVITIES OF IMLILY SEBKHAT IN SOUTHWESTERN MOROCCO .................... 113

Hakdaoui Sofia, Emran Anas (Wednesday 25 April 2018: 15h00)

S.08O13: CONTRIBUTION OF THE THERMAL INFRARED BAND OF LANDSAT SENSORS (TM & ETM+) TO SPATIOTEMPORAL MONITORING OF SURFACE WATER TEMPERATURE ALONG THE AL MASSIRA LAKE BETWEEN 1987 AND 2017 ....................................................................................................... 114

Aitelghazi Abdellah, Rhinane Hassan, Bensalmia Ahmed (Wednesday 25 April 2018: 15h20)

S.08O14: SEISMOTECTONICS OF THE 2017 BOTSWANA EARTHQUAKE (MW 6.5): AN ACTIVE BRANCH OF THE EAST AFRICAN RIFT ........................................ 115

Meghraoui Mustapha, Midzi Vunganai, Mohamed Saleh (Wednesday 25 April 2018: 15h40)

S.08015: GEODYNAMIC FRAMEWORK OF THE NORTHERN AFRICAN MARGIN IN TUNISIA : IMPLICATION FOR SEISMOGENIC POTENTIAL ............................. 116

Bouaziz Samir (Wednesday 25 April 2018: 16h40)

S.08016: SEISMIC WAVE VELOCITY AND GEODYNAMIC EVOLUTION IN NW OF WEST AFRICAN CRATON : CASE OF THE MOROCCAN MESETA ? ATLAS DOMAIN ......................................................................................................................... 117

Timoulali Youssef, Jabour Nacer (Wednesday 25 April 2018: 17h00)

S.08017: CONTRIBUTION OF RADAR SATELLITE IMAGES IN RELIEF STUDYING IN THE PROVINCE OF AL-HOCEIMA ............................................................................... 118

Boulaassal Hakim, Annaki Sara, El Kharki Omar (Wednesday 25 April 2018: 17h20)

S.08O18: TROPOSPHERIC WATER VAPOR CORRECTION MODEL FOR INSAR USING ENVISAT/ASAR-MERIS DATA............................................................................... 119

Aguemoune Samir, Abdelhakim Ayadi, Belhadj-Aissa Aichouche (Wednesday 25 April 2018: 17h40)

S.08P01: ETUDE ANALYTIQUE DES LINÉAMENTS MORPHO-STRUCTURAUX DU RIF CENTRAL (MAROC) ............................................................................................... 120

Moussaoui Siham, Azzouz Omar (Wednesday 25 April 2018: Poster session)


xviii

S.08P02: SEISMIC ANISOTROPY OF NORTH ALGERIA FROM SHEAR-WAVE SPLITTING ANALYSIS ............................................................................................................. 121

Radi Zohir, Yelles-Chaouche Abdelkrim (Wednesday 25 April 2018: Poster session)

S.08P03: INTERFEROMETRY SAR ANALYSIS OF AL HOCEIMA (MOROCCO) DEFORMATION DUE TO A 6.3 MW EARTHQUAKES ON THE 25/01/2016 USING SENTINEL-1A IW. ..................................................................................................... 122

Muhire Desire, Yassine Tounsi, Ahmed Siari et al., (Wednesday 25 April 2018: Poster session)

S.08P04: USING MAPPING DATA AND REMOTE SENSING TO GENERATE A 1/100 000 SCALE GEOLOGICAL MAP (AGDZ, MOROCCAN ANTI-ATLAS) ................. 123

Elmortaji Nizar, El Kharki Omar, Boulaassal Hakim et al., (Wednesday 25 April 2018: Poster session)

S.08P05: APPLICATIONS OF MULTISPECTRAL REMOTE SENSING TECHNIQUES TO UPDATE THE GEOLOGICAL MAP OF AL-MAGHRABAH AREA, HAJJAH PROVINCE, YEMEN .................................................. 124

Alnahmi Fuad, Hilali Atika, Rhinane Hassan et al., (Wednesday 25 April 2018: Poster session)

S.08P06: IS THE NUBIA PLATE RIGID OR DIVIDED INTO SUB-PLATES? INSIGHTS FROM GEODETIC DATA AND THE SEISMOTECTONIC MAP OF AFRICA .......................................................................................................................................................... 125

Mukandila Ngalula Raphael, Masson Frederic, Meghraoui Mustapha (Wednesday 25 April 2018: Poster session)

S.08P07: APPORT DES IMAGES SATELLITAIRES ET DES MODÈLES NUMÉRIQUES DE TERRAIN À LA RECONAISSANCE ET LA CARTOGRPHIE DES STRUCTURES NÉOTECTONIQUE AU NE DE L'ALGÉRIE ...................................................................................................................................126

Mohammedi Yahia, Hamidatou Mouloud (Wednesday 25 April 2018: Poster session)

S.08P08: LAND USE/LAND COVER IN SAISS PLAIN, USING REMOTE SENSING TECHNIQUES ............................................................................................................................. 127

El Hafyani Mohammed, Essahlaoui Ali, Mohajane Meriame et al., (Wednesday 25 April 2018: Poster session)

S.08P09: GEODYNAMIC EVOLUTION OF BOUKAÏS-EL AHMER AREA (NORTH BECHAR, SW ALGERIA) : USING REMOTE SENSING AND FIELD DATA ......... 128

Chabane Sarah, Amri Kamel, Hamdidouche Rachid (Wednesday 25 April 2018: Poster session)

S.08P10: ESTIMATION OF LAND DEFORMATION IN OILFIELDS BY MEANS OF DINSAR, CASE STUDY IN-SALLAH, ALGERIA ............................................................. 129

Smail Tayeb, Abed Mohamed, Fatma Canaslan çomut (Wednesday 25 April 2018: Poster session)

S.08P11: MEASURING DEFORMATION DUE TO 2016 NEW ZEALAND MW7.8 EARTHQUAKE BY USING GNSS PRECISE POINT POSITIONING TECHNIQUE ............................................................................................................................... 130

Allal Saddam Housseyn, Dekkiche Hichem, Bouguern Abderrahmane (Wednesday 25 April 2018: Poster session)


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S.09: EDUCATION, OUTREACH & COMMUNICATION

S.09P01: THE IMPACT OF CLIMATE CHANGES IN THE WATER RESOURCES IN THE PLAIN OF THE GHARB (WESTERN NORTH OF MOROCCO) ..................... 131

El Houyr Said, Kachtali Mohammed (Wednesday 25 April 2018: Poster session)

S.09P02: IDENTIFICATION SISMIQUE DE LA STABILITÉ D'UN BÂTIMENT DANS LA MULTI-PHASE NON LINÉAIRE PAR UN SYSTÈME DE CONTREVENTEMENT DE FRP........................................................................................... 132

Taoufik Tbatou, Elyoubi Mohamed (Wednesday 25 April 2018: Poster session)

S.09P03: THE EDUCATIONAL SEISMIC STATION PRINCESS LALLA AICHA OF AGADIR ........................................................................................................................................ 133

El Kilali El Hassan, Es-Saady Youssef (Wednesday 25 April 2018: Poster session)

S.09P04: INDICATORS IN RISK MANAGEMENT : A FRESH PERSPECTIVE BETWEEN HAZARD ANALYSES AND SOCIETIES' RESPONSES ........................... 134

Ivcevic Ante, Mazurek Hubert, Siame Lionel (Wednesday 25 April 2018: Poster session)

S.09P05: CURRENT STATUS OF THE ISC BULLETIN ................................................................ 135

Shumba Blessing (Wednesday 25 April 2018: Poster session)


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Program Schedule

Monday 23 April 2018 Room A Room B 08h30 10h00

Registration and Opening speech

10h00 10h40

Coffee Break & Poster Session

10h40 11h10

C01 Meghraoui Mustapha

11h10 11h40

C02 Reilinger Robert et al.,

11h40 12h10

C03 Bensari Driss

12h10 14h00

Break

Session 1 Active Tectonics, Paleoseismology and Historical Seismicity

Session 2 Seismic source/Induced seismicity

14h00 14h20

S.01O01 Atalay Ayele

S.02O01 Hassoup Awad

14h20 14h40

S.01O02 Chlieh Mohamed et al.,

S.02O02 Durrheim Raymond et al.,

14h40 15h00

S.01O03 El Moudnib Lahcen

S.02O03 El Ouai Driss et al.,

15h00 15h20

S.01O04 Abdelhakim Ayadi et al.,

S.02O04 Abderrahman Elmahsani et al.,

15h20 15h40

S.01O05 Myendeki Sinovuyo

S.02O05 Khelif Mohamed Fadhlallah et al.,

15h40 16h00

S.01O06 Galindo-Zaldivar Jesus et al.,

S.02O06 Zulu Brian Sibonelo

16h00 16h40


16h40 17h00

S.01O07 Nacer Jabour

S.02O07 Beldjoudi Hamoud

17h00 17h20

S.01O08 Maouche Said et al.,

S.02O08 Boulanouar Abderrahim

17h20 17h40

S.01O09 Lambarki Drissi Ibtissam et al,

17h40 18h00

S.01O10 Abdel-Aal Abdel-Aziz, Mostafa Shaimaa

18h30 20h00

UNESCO - IGCP-659 Business and kickoff Meeting

Tuesday 24 April 2018 Room A Room B

Session 3 Ground motion and site effects

Session 4 Tsunami hazard : data collection and modelling

08h40 09h00

S.03O01 Fontiela Joao et al.,

S.04O01 El Moussaoui Said et al.,

09h00 09h20

S.03O02 Mohammed Touati et al.,

S.04O02 Benamri Sofia et al.,


xxi

09h20 09h40

S.03O03 Amponsah Paulina et al.,

S.04O03 Meghraoui Mustapha et al.,

09h40 10h00

S.03O04 Maklad Mohamed et al.,

S.04O04 Salama Asem et al.,

10h00 10h40


10h40 11h00

S.03O05 Mulabisana Thifhelimbilu, Midzi Vunganai

S.04O05 Kherroubi Abdelaziz et al.,

11h00 11h20

S.03O06 Smailhodzic Hrustem

S.04O06 Korchy Hanan et al.,

11h20 11h40

S.03O07 Chaaraoui Aboubakr et al.,

S.04O07 Benchekroun Sabah

11h40 12h00

S.03O08 Ayad Abderrrahim, Bakkali Saad

12h00 14h00

Break & Poster Session

Session 5 Earth structures in Africa/The East African Rift System

Session 6 GIS and Risk Scenario

14h00 14h20

S.05O01 Raveloson Andriamiranto et al.,

S.06O01 Cherif Seif Eddine et al.,

14h20 14h40

S.05O02 Faried Ahmad M et al.,

S.06O02 Fathi Badr-Eddine et al.,

14h40 15h00

S.05O03 Rekik Dhouha et al.,

S.06O03 Tahouri Jad et al.,

15h00 15h20

S.05O04 Hosny Ahmed

S.06O04 Al-Mahfadi Afrah et al.,

15h20 15h40

S.05O05 Midzi Vunganai et al.,

S.06O05 Hakdaoui Sofia, Emran Anas

15h40 16h00

S.06O06

Ouallali Abdessalam et al., 16h00 16h40


16h40 19h00

AfSC Business meeting

Wednesday 25 April 2018 Room A Room B

Session 7 Earthquake Hazard Assessment

Session 8 Geodynamics, GPS, InSAR and remote sensing

08h40 09h00

S.07O01 Hassan Hany et al.,

S.08O01 Said Benchelha et al.,

09h00 09h20

S.07O02 Benouar Djilali

S.08O02 Boukerbout Hassina et al.,

09h20 09h40

S.07O03 El Mahsani Abderahman et al.,

S.08O03 Yelles Abdelkarim et al.,

09h40 10h00

S.07O04 Tahouri Ouassim et al.,

S.08O04 Hamai Lamine et al.,

10h00 10h40


10h40 11h00

S.07O05 Ksentini Ahmed et al.,

S.08O05 Fatima Ezzahrae Al Makkassi et al.,

11h00 11h20

S.07O06 Delvaux Damien et al.,

S.08O06 Bougrine Amina et al.,

11h20 11h40

S.07O07 Ateba Bekoa et al.,


11h40 12h00

S.07O08 Mohamed Hamdache et al.,

S.08O08 Bouyahiaoui Boualem et al.,

12h00 14h00

Break & Poster Session


xxii

14h00 14h20

S.07O09 Mavonga Tuluka Georges et al.,

S.08O09 Tahayt Abdelilah et al.,

14h20 14h40

S.07O10 Kariche Jugurtha et al.,

S.08O10 Fadil Abdelali et al.,

14h40 15h00

S.07O11 Athmouni Malak et al.,

S.08O11 Mahyoub Sulaiman et al.,

15h00 15h20

S.07O12 Manzunzu Brassnavy et al.,

S.08O12 Hakdaoui Sofia et al.,

15h20 15h40

S.08O13 Aitelghazi Abdellah et al.,

15h40 16h00


16h00 16h40 Coffee Break Poster Session

16h40 17h00

S.08O15 Bouaziz Samir

17h00 17h20

S.08O16 Timoulali Youssef

17h20 17h40

S.08O17 Boulaassal Hakim

17h40 18h00

S.08O18 Aguemoune Samir

18h00 19h00

General Discussion and Recommendations (Cloture): The future of AfSC and the Earthquake Data Centre for Africa

Thursday 26 April 2018 Room A

09h00 12h00

Practical Training Courses 1: Seismotectonics & NDC in a Box Package: Access and Analysis of Waveform IMS Data and IDC Products.

Mustapha Meghraoui, Vunganai Midzi, Youssef Timoulali, Abdelhakim Ayadi & IDC/CBT 12h00 14h00

Break

14h00 18h00

Practical Training Courses 1: Seismotectonics & NDC in a Box Package: Access and Analysis of Waveform IMS Data and IDC Products.

Mustapha Meghraoui, Vunganai Midzi, Youssef Timoulali, Abdelhakim Ayadi & IDC/CBT

Friday 27 April 2018 Room A

09h00 12h00

Practical Training Courses 2: Radar interferometry and its applications Omar El Kharki, Hakim Boulaassal

12h00 14h00

Break

14h00 18h00

Practical Training Courses 2: Radar interferometry and its applications Omar El Kharki, Hakim Boulaassal

xxiii

Abstracts

Plenary session 1

Active Tectonics, Paleoseismology and Historical Seismicity 3

Seismic source / Seismic source/Induced seismicity 24

Ground motion and site effects 39

Tsunami hazard : data collection and modelling 50

Earth structures in Africa/The East African Rift System 60

GIS and Risk Scenario 69

Hazard Assessment 80

Geodynamics,GPS, InSAR and remote sensing 102

1

*Corresponding author Meghraoui Mustapha <[email protected]>

Conference: Plenary session https://afsc2018.sciencesconf.org/192991/

C.01: EARTHQUAKES IN AFRICA: THE SEISMOTECTONIC AND SEISMIC HAZARD PERSPECTIVES

Meghraoui Mustapha 1

1 - Institut de Physique du Globe, CNRS-UMR 7516 (France)

Abstract

The African continent was the site of several destructive earthquakes with moment magnitude Mw ?6.5 since the beginning of the 20th century. Some of these earthquakes are shallow and some of them revealed surface faulting with prominent coseismic slip that can be correlated with seismotectonic structures (plate boundaries, rift systems, transform faults and active intraplate regions). Their occurrence in densely populated areas with increase in building plans caused severe damage and significant economic losses in Africa. Among the oldest major seismic events reported in Africa is the 1200 BC Thebes earthquake that destroyed the Memnon Colossi and Amenhotep III temple in the Nile Valley. Other damaging earthquakes such as the 1862 Ghana (Mw 6.6), 1911 Cameroun (Mw 6.0), 1920 Cape Town (Mw 6.2), 1974 Gabon (Mw 6.1), 1983 Guinea (Mw 6.2) and the 2017 Botswana (Mw 6.5) took place in regions usually considered as ?stable? continental interiors. The recently prepared seismotectonic map of Africa displays the main seismically active zones along with their stress and strain distribution, volcanic fields, and crustal and lithospheric structures 1. The seismic hazard and risk assessments in Africa have always been a challenge in the absence of a complete database that includes well located earthquakes, active faulting and strain rates across the continent (2, 3). The difficulty rises in that many regions remain poorly studied. Following the recent increase of seismic and GPS stations, the plans for an Earthquake Data Centre in Africa along with progress in projects such as SEISMOSHAF leave optimistic perspectives for a realistic earthquake hazard and risk assessment in Africa.

Keywords: Seismotectonics, seismic hazard, risk, perspectives

2

*Corresponding author Reilinger Robert <[email protected]>

Conference: Plenary session https://afsc2018.sciencesconf.org/192173/

C.02: GLOBAL POSITIONING SYSTEM (GPS) CONTRIBUTIONS TO ACTIVE TECTONICS IN AND BORDERING AFRICA

Reilinger Robert 1, King Robert 1, Floyd Michael 1, Tahayt Abdelilah 2, Taoufik Mourabit 3, Ben Sari Driss 4, Barazangi Muawia 5, Vernant Philippe 6, Davila Jose 7, Ogubazgi Ghebrebrhan 8, Vitres Renier 9, Jonsson Sigurjon 9, Mcclusky Simon 10, Koulali Achraf 11, Gomez Francisco 12,

Lewi Elias 13, Bendik Rebbeca 14

1 - Massachusetts Institute of Technology (United States), 2 - Université Mohammed V-Agdal (Morocco), 3 - Université Abdelmalek Essaadi (Morocco), 4 - Private citizen (Morocco), 5 - Cornell University (United States), 6 - Géosciences Montpellier (France), 7 - Royal Observatory Aramada (Spain), 8 - Eritrean Institute of Technology (Eritrea), 9 - King Abdullah University of Science and Technology (Saudi Arabia), 10 - Research School of Earth Sciences, Australian National University (Australia), 11 - Australia National University (Australia), 12 - University of Missouri-Columbia (United States), 13 - Addis Ababa University (Ethiopia), 14 - University of Montana (United States)

Abstract

Since 1994, MIT and a broad group of African, and other international partners have been using the Global Positioning System (GPS) to map and investigate active deformations within and on the borders of the African continent. GPS estimates of Nubia plate motion with respect to (wrt) Eurasia (i.e., Nubia-Eurasia Euler Vector), indicate counterclockwise rotation of Nubia with oblique convergence increasing from ~5 - 7 mm/yr from Gibraltar to Egypt, with internal deformation of Nubia constrained to <0.6 mm/yr away from active plate boundaries. Convergence is accommodated by subduction and collision, including the M7.1, 1980 El Asnam, Algeria earthquake, the tsunami generating subduction earthquake on the Hellenic arc in 365 AD, and the deadly 1755 Great Lisbon Earthquake that occurred offshore of the Gibraltar Strait. In the westernmost Mediterranean, GPS observations in Morocco and in southern Spain beginning in 1998 indicate oblique convergence across the Alboran Sea. Complex internal deformation in Morocco extends ~400 km into the Nubian Plate to the Anti Atlas Mountains, including slow shortening across the Atlas Mountain system, and southwest motion and clockwise rotation of the Rif wrt Nubia and associated deformation in southernmost Spain. This deformation gives rise to significant earthquakes throughout this region. Opening along the Red Sea Nubia-Arabia plate boundary, and the Gulf of Aden Somalia-Arabia boundary are both well constrained on a plate-wide scale, with opening rates along the Red Sea increasing from ~7 - 20 mm/yr from the Suez south to the southernmost Red Sea. The Sinai region appears to move northward at about 1 mm/yr wrt Nubia with deformation focused in the Gulf of Suez. In the southern Red Sea the southern end of the Danakil block is attached to the Arabian Plate and the northern end to Nubia (although beginning to detach) causing opening (~ 20 mm/yr) of the southern Danakil Depression and Afar Triple Junction region. The East African Rift (EAR) is the largest tectonic feature in Africa extending ~4000 km from the southern Afar (~5°N) to ~ 30°S latitude. Mapping deformation along the EAR is a primary focus of the GeoPRISM East African Rift Project involving a large consortium or participants. Rates of extension across the Rift increase from less than 1 mm/yr in the southernmost Rift to ~6-7 mm/yr at the Latitude of Addis Ababa. In this presentation, we will briefly describe present GPS Geodynamic control in these focus areas, our most recent GPS-site velocity estimates, and initial results and implications for active tectonic processes.

Keywords: GPS, tectonic deformation, Plate motions, InSAR

3

*Corresponding author Atalay Ayele <[email protected]>

Oral: Active Tectonics, Paleoseismology and Historical Seismicity https://afsc2018.sciencesconf.org/197908/

S.01: RECENT SEISMICITY AND EARTHQUAKE RISK IN ETHIOPIAN CITIES

Atalay Ayele 1

1 - Addis Ababa University (Ethiopia)

Abstract

The East African Rift is the classic examples of active continental rifts that we witness to date. Active tectonics manifests through moderate magnitude seismicity and volcanism in the region. Major cities and towns in Ethiopia are located within the active rift floor or the nearby margins where small farming villages were highly urbanized over the years, which is unintended overlap that exacerbated earthquake risk in the country. The January 24, 2016 earthquake of magnitude 4.4 Nw occurred nearby the populated Awasa town at 18:34:32 UTC which was felt all over the town with minor damage on buildings. The Awasa University students panicked from high-rise student dormitories and minor injuries were reported. Another earthquake of magnitude 4.6 MI occurred on December 4, 2016 at 01:56:15 UTC at the rift margin 40 km south of Ankober town and about 90 km NNE of Addis Ababa. It was widely felt in Addis Ababa where a number of residents reported their feeling to the media. On January 27, 2017 an earthquake of magnitude 5.3 Mw ruptured at 16:29:23 UTC, 160 km south of Addis Ababa just on the eastern side of Lake Langano. This earthquake was widely felt in most of rift valley towns in Ethiopia as far as Addis Ababa. Addis Ababa being one of the fastest growing cities in sub-Saharan Africa and as the capital of Africa, there is a threat due to potential earthquake risk which has never got due attention by the concerned stakeholders. The Ethiopian Seismic Station Network (ESSN) is beaming real-time data, though limited by frequent power failure and poor internet connectivity, for monitoring earthquake and volcanic activity in the Horn of Africa region. However, awareness in the society is still low which demands a coordinated effort in the years ahead so as to mitigate possible earthquake crisis.

Keywords: Seismicity, Earthquake, Risk, Ethiopia

4

*Corresponding author Chlieh Mohamed <[email protected]>


S.01: ACTIVE TECTONICS OF PERU: HETEROGENEOUS INTERSEISMIC COUPLING ALONG THE NAZCA MEGATHRUST, RIGID MOTION OF THE PERUVIAN SLIVER, AND SUBANDEAN SHORTENING ACCOMMODATION

Chlieh Mohamed 1, Villegas Lanza Juan Carlos 2, Cavalié Olivier 3, Tavera Hernando 2, Baby Patrice 4

1 - Institut des Sciences de la Terre (France), 2 - Instituto Geofisico del Peru (Peru), 3 - Geoazur (France), 4 - Géosciences Environnement Toulouse (France)

Abstract

Over 100 GPS sites measured in 2008?2013 in Peru provide new insights into the present-day crustal deformation of the 2200 km long Peruvian margin. This margin is squeezed between the eastward subduction of the oceanic Nazca Plate at the South America trench axis and the westward continental subduction of the South American Plate beneath the Eastern Cordillera and Subandean orogenic wedge. Continental active faults and GPS data reveal the rigid motion of a Peruvian Forearc Sliver that extends from the oceanic trench axis to the Western-Eastern Cordilleras boundary and moves southeastward at 4?5 mm/yr relative to a stable South America reference frame. GPS data indicate that the Subandean shortening increases southward by 2 to 4 mm/yr. In a Peruvian Sliver reference frame, the residual GPS data indicate that the interseismic coupling along the Nazca megathrust is highly heterogeneous. Coupling in northern Peru is shallow and coincides with the site of previous moderate-sized and shallow tsunami-earthquakes. Deep coupling occurs in central and southern Peru, where repeated large and great megathrust earthquakes have occurred. The strong correlation between highly coupled areas and large ruptures suggests that seismic asperities are persistent features of the megathrust. Creeping segments appear at the extremities of great ruptures and where oceanic fracture zones and ridges enter the subduction zone, suggesting that these subducting structures play a major role in the seismic segmentation of the Peruvian margin. In central Peru, we estimate a recurrence time of 305 ± 40 years to reproduce the great 1746 Mw~8.8 Lima-Callao earthquake.

Keywords: Continental Deformation, Active Tectonics, Seismic cycle

5

*Corresponding author El Moudnib Lahcen <[email protected]>


S.01: PRESENT-DAY SEISMOTECTONICS BENEATH THE RIF-ATLAS AREA, MOROCCO, FROM EARTHQUAKE FOCAL MECHANISM DATA

El Moudnib Lahcen 1

1 - Geophysics & Natural Risks Laboratory, Institut Scientifique, Geophysics, Natural Patrimony and Green Chemistry Research Center, Mohammed V University in Rabat. Morocco. (Morocco)

Abstract

New focal mechanisms have been obtained for 48 earthquakes occurred beneath the earth crust of Morocco and surrounding region during the time period of 2008 to 2014. For this aim, a high quality waveform data were recorded in local and regional seismic networks of more than 100 broadband stations. Relocated of the moderate earthquakes with HYPOCENTRE Program, ranging in moment magnitude Mw from 3.5 to 4.8, were introduced to the FOCMEC software in order to get the fault plane solution of the area study. The obtained focal mechanisms from P-first motion data indicate variability in mechanism type, but the reverse and strike-slip faulting are the predominant mechanisms observed for the analyzed events. We can distinguish three major groups of focal mechanisms basing on the orientation of the P-axes. The first one is characterized by near-horizontal P-axes oriented in an approximately NW-SE direction that coincides with the direction of convergence between Africa and Eurasia. The characteristic of this focal mechanism group corresponds to earthquakes in the Altas and NE Morocco. The second group of earthquakes located in western zone of Middle Atlas, are characterized by a heterogeneous faulting pattern that indicates a variation of local stress conditions. Two earthquakes reveal a reverse fault-plane with the P-axes oriented in NNW-SSE direction and the two others shows a heterogeneous fault with almost the same directions. The third group of focal mechanisms are characterized as well by horizontal P-axes and almost perpendicular to the first group, but oriented in a SW-NE direction. The corresponding earthquakes are distributed in the western Rif and are part of a cluster located north of Ouezzane. The western Rif dynamic, from recent GPS data, shows a slight movement in SW direction with respect to the Nubian plate. This movement direction is consistent with the third cluster of mechanisms.

Keywords: Atlas, Rif, Tectonics, P axes, Focal Mechanisms, Moderate Earthquakes,

Morocco

6

*Corresponding author Abdelhakim Ayadi <[email protected]>


S.01: GEOLOGY, TECTONIC AND DEEP PROCESS IN THE HOGGAR SWELL (ALGERIA)

Abdelhakim Ayadi 1, Meghraoui Mustapha 2, Said Maouche 1

1 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria), 2 - Institut de Physique du Globe, Université de Strasbourg (France)

Abstract

Geological and Geophysical investigations were performed over the Hoggar region to better understand its inner structure, origin and the related Neogene and Quaternary volcanic activity. The Hoggar shield is a broad area of exposed Precambrian basement bounded by Paleozoic and Mesozoic basins. From the neotectonic point of view, field investigations were conducted along the Oued Amdad volcanic area in the Serouanout Cretaceous sedimentary basin (eastern Hoggar), and the meridional shear zones. Maouche et al. (2014) show that the region is characterized by various tectonic features including normal, thrust and strike-slip faults affecting Cenozoic sedimentary series. Recent field analysis shows an extensive normal fault network that affects both the sedimentary series and the volcanic rocks that spread over the central Hoggar in various districts. The normal fault distribution seems to be related to post-volcanic tectonic activity, within a time span from Miocene to Quaternary. The Hoggar region is composed of three contrasted lithostructural and metamorphic domains separated by N-S trending shear zones that form the central Hoggar, the Pharusian belt and the In-Ouzal domain. The seismic tomography performed by Ayadi et al. (2000) shows the existence of hot material (large thermal anomaly) under the central Hoggar extending down to the lithosphere. These observations are also supported by gravity anomalies (Lesquer and Vasseur 1992) attributing the large low density anomaly to the melting at the lithosphere/asthenosphere interface under the central Hoggar. The intraplate tectonic activity of the Hoggar massif can be correlated to the Cenozoic volcanism but the seismic activity still under debate.

Keywords: Active fault, Cenozoic Volcanism, Hoggar Swell

7

*Corresponding author Myendeki Sinovuyo <[email protected]>


S.01: USE OF EARTHQUAKE LOCATIONS TO IDENTIFY SEISMOGENIC STRUCTURES IN THE WITWATERSRAND BASIN, SOUTH AFRICA

Myendeki Sinovuyo 1

1 - Council For Geoscience (South Africa)

Abstract

The Witwatersrand Basin has experienced a number of tectonic episodes leading to formation of faults in the crust. In the same way that these tectonics instigate to formation of intricate fault and dyke patterns, they facilitate the distribution of orebodies. Thus, Witwatersrand basin is home to some of the deepest and ultra-deep gold mines in the world that consequently are also well-known for previous rockbursts. The numerous occurring events in the region are suggested to be mining related. Previous investigations in the region have indicated mining and exploration activities in the Witwatersrand basin to be responsible for faulting and folding. This study aims to identify seismogenic structures which can be associated with earthquake locations within clusters of seismicity in the region. The seismicity clusters being investigated are situated in the Witwatersrand Basin and the clusters are in the Klerksdorp, Carletonville and Johannesburg area. Clusters were demarcated based on large earthquakes that took place in the region in the past. However, the occurring seismicity differs; varying from tectonic to mining sources. To better understand the sources of these events an effort was made to study the geology of the area. In outlining the geology encompasses the area, ArcGIS was utilised in mapping the faults, dykes and joints and including major faults that were previously linked to earthquakes. A seismogenic structure is referred as a structure that has resulted from an earthquake event, and can generate a new earthquake in the future. This study will verify whether the earthquakes are occurring on the lineament or dykes mapped in this region. Potential fault sources of moderately sized earthquakes (M > 3.0) were identified and targeted for field investigations to determine the stress regime.

Keywords: seismogenic

8

*Corresponding author Galindo-Zaldivar Jesus <[email protected]>


S.01: VERY RECENT SEABOTTOM DEFORMATION IN THE AREA AFFECTED BY THE 2016-2017 SEISMIC CRISIS IN THE ALBORAN SEA (WESTERN MEDITERRANEAN)

Galindo-Zaldivar Jesus 1, Ercilla Gemma 2, Estrada Ferran 2, Catalán Manuel 3, D'acremont Elia

4, Azzouz Omar 5, Casas David 6, Chourak Mimoun 7, Vazquez Juan Tomás 8, Chalouan Ahmed

9, Sanz De Galdeano Carlos 10, Benmakhlouf Mohamed 11, Gorini Christian 4, Alonso Belén 2, Palomino Desiree 8, Rengel Juan 12, Gil Antonio José 13

1 - Dpto. de Geodinamica, Universidad de Granada /Instituto Andaluz de Ciencias de la Tierra, CSIC- Univ. Granada. (Spain), 2 - Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona] (Spain), 3 - Real Instituto y Observatorio de la Armada (Spain), 4 - Institut des Sciences de la Terre de Paris (France), 5 - Université Mohammed Premier (Morocco), 6 - Instituto Geológico y Minero de España (Spain), 7 - Ecole nationale des sciences appliquées Oujda (Morocco), 8 - Instituto Español de Oceanografía (Spain), 9 - Université Mohamed V de Rabat (Morocco), 10 - Instituto Andaluz de Ciencias de la Tierra, CSIC- UGR (Spain), 11 - Faculté des Sciences, Université Abdelmalek Essaadi (Morocco), 12 - Instituto Hidrográfico de la Marina (Spain), 13 - Dpto. Ing. Cartográfica, Geodesia y Fotogrametría, CEAC Tierra Universidad de Jaén, (Spain)

Abstract

The Alboran Sea (Westernmost Mediterranean) is a Neogene basin located between the Betic and Rif cordilleras that undergoes shortening and orthogonal extension due to the Eurasian-African NW-SE oblique plate convergence. A NNE-SSW broad band of deformation and seismicity affects its central part extending from the northern Rif (Trougout Fault), the Alboran Sea (Al Idrisi Fault), to southern Betics (Balanegra Fault). After the 1993-1994 and 2004 seismic series, a new crisis shocked mainly the southern Alboran Sea in 2016-2017 (main event Mw=6.3, Jan 25). The nearsurface recent seafloor deformation of this area is investigated using seismic profiles, multibeam and gravimeter data, recovered during the INCRISIS cruise. Epicenters grouped into two main branches. The northern WSW-ENE branch parallels the northern face of the Alboran Ridge- Francesc Pagès seamount antiforms and intersects the Al Idrisi Fault. Mass-transport deposits occurred at least since recent times. The southern branch, that crosses the Francesc Pagès seamount and Nekor Basin, consists of a NNE-SSW vertical sinistral deformation zone, with early epicenters of higher magnitude earthquakes located along a narrow band paralleling the 10 km far east Al Idrisi Fault. Nearsurface deformation includes active NW-SE vertical and normal faults, unmapped until now. Later, the epicenter band spreads eastward, reaching the main Al Idrisi Fault characterized by discontinuous active NE-SW vertical fractures. Seismicity and tectonic structures suggest a westwards propagation of deformation and the growth of very recent incipient faults, comprising NNE-SSW sinistral fault zone in depth that is connected upwards with NW-SE vertical and normal faults. This new fault zone is segmented, including 1994 seismicity in coastal area, that propagates 2004 onshore and 2016 offshore. The new insights for the seismic hazard assessment, point to the growth of new faults can produce potential high magnitude earthquakes than already formed faults.

Keywords: mass transport deposits, earthquakes, fracture development, African plate

boundary, Eurasian, active sea bottom deformations

9

*Corresponding author Nacer Jabour <[email protected]>


S.01: AL HOCEIMA NORTHERN MOROCCO 1994, 2004 AND 2016 SEISMIC SEQUENCES

Nacer Jabour 1

1 - Centre National de la Recherche Scientifique et Technologique (Morocco)

Abstract

The earthquakes series associated with the major events that have affected the Al Hoceima region in 1994, 2004 and recently in 2016 are presented here together to show the spatial and temporal dependency of the events. The complexity of the geologic setting both in land and off-shore is governing the source process of the main shocks as well as the spatial distribution of the foreshocks and aftershocks. The foreshocks corresponding to these major shocks show also a different behavior in particular when comparing the 1994 and 2016 events distribution. The aftershocks corresponding to the each major event overlap spatially in a large proportion meaning that the faults systems were either loaded to the rupture limit as indicated by prompt aftershocks or left without triggering for the coming major event. The focal mechanisms obtained from a number of events together with these observations reflect clearly the local variation of the stress regime which is probably due to the complexity of this part of the Maghreb-Iberia plate boundary. The ground motion records obtained from these major events show more the site effects or the local soil conditions as an important parameter in seismic hazard assessment.

Keywords: strong ground motion, aftershocks, main shock, foreshocks

10

*Corresponding author Harbi Assia <[email protected]>


S.01: THE ACTIVE FAULTS OF THE MITIDJA BASIN (NORTH CENTRAL ALGERIA): WHAT DOES THE SEISMIC HISTORY OF THE REGION TELL US?

Maouche Said 1, Harbi Assia 1

1 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria)

Abstract

It is very rare in Northern Algeria, which is an active seismic zone that a rupture reaches the surface. This makes difficult the definition of the characteristic parameters of any active fault. In this paper we combine our own field observations with available geological maps, measurements of neotectonic ruptures, geomorphological data, and the results obtained in recent investigations of historical and instrumental seismicity to help comprehend the complexity of the active deformation of the Mitidja basin (MB). Our analyses reveal the tectonic characteristics of the Mitidja basin and indicate that the seismic activity is essentially concentrated along the system of the boundary faults. The general structural shape of the seismogenic Mitidja basin suggests that the southern fault system would mimic the northern fault system and we observe a highest seismicity rate at the junction point of the NW-SE fault and the south thrust faults system.

Keywords: Algeria, Mitidja basin, historical earthquakes, active tectonics

11

*Corresponding author Lambarki Drissi Ibtissam <[email protected]>


S.01: THE SEISMITES OF THE PLEISTOCENE FORMATIONS IN THE NORTH-EAST OF RABAT AS AN INDICATOR OF PREHISTORIC EARTHQUAKES AND PROBABLE PRECURSOR OF THE LISBON EARTHQUAKE OF 1755 AD.

Lambarki Drissi Ibtissam 1, Aberkane M'hamed 1

1 - Faculty of sciences Rabat (Morocco)

Abstract

Geological phenomena such as tectonics and volcanism, as well as their consequences such as earthquakes, have existed since the dawn of the history of earth, long before the arrival of man and the discovery of seismographs which, currently, record almost instantly every earthquake of our planet. However, nature has its own seismographs which are sediments. Their geological proprieties allow them to record marks left by earthquakes in the form of sedimentary figures that provide information about the occurrences of seismic activities. The geologist calls seismites sedimentary beds marked and disturbed by seismic activity. The appearance of these figures depends as much on the lithological nature of the deposits and their environmental context, as on the strength of the earthquake to modify the organization of the materials during their sedimentation and before their consolidation. Sedimentary paleo-seismicity indices are well preserved, particularly in lacustrine deposits, making it possible to locate and estimate prehistoric and historical paleoseisms (Pascua, 2004). In the coastal area of the Moroccan Atlantic coast north-east of Rabat, Quaternary formations recorded a diversity of seismic figures. For example, those marked in marine, lagoon and dune deposits belonging to the Pleistocene (dated 220ka to 110 ka BP).These records indicate seismic activity of magnitude on the order of 7 on the Richter scale, which could be attributed to prehistoric earthquakes and considered as distant precursors of historical catastrophic earthquakes that affected the Atlantic Iberian and Moroccan fringe, such as the Lisbon earthquake of 1755 and that of 1969 AD. A precise cartography of the distribution of these seismites would contribute to the comparison between prehistoric, historical and current seismicity maps and elaborate database of the evolution of regional seismicity to aid in the assessment of the seism hazard, and takes preceding measures in the prospects of a possible seismic risk prediction.

Keywords: Earthquakes, seismites, paleoseismicity, precursors, Lisbon earthquake,

Quaternary, Atlantic coast, Morocco.

12

*Corresponding author Abdel-Aal Abdel-Aziz <[email protected]>


S.01: REVIEW IN SEISMOTECTONIC SETTING OF GULF OF AQABA WITH RESPECT TO THE 27 JUNE 2015 AND 16 MAY 2016 AQABA EARTHQUAKE SWARMS

Abdel-Aal Abdel-Aziz 1, Mostafa Shaimaa 2

1 - National Research Institute of Astronomy and Geophysics (Egypt), 2 - Zagazig University, Faculty of Science, Geology Department, (Egypt)

Abstract

In this manuscript, we review recent seismicity and seismotectonic setting of Gulf of Aqaba, based on two recently significant swarms occurred on 27 June 2015 and 22 May 2016. Seismologically, the Gulf of Aqaba is one of the most active places around Egypt, where several earthquake swarms have occurred through ancient and modern times. In the last century, five earthquake swarms of 1983, 1990, 1993 and 1995 have been instrumentally recorded. Recently, on 27 June 2015 a swarm of 96 earthquakes with local magnitudes ranging from 0.7 to 5.2 were recorded by the Egyptian National Seismological Network (ENSN). On 16 May 2016 another swarm started and continued for several consecutive days, and approximately 99 events with local magnitudes ranging from 0.5 to 4.9 .was instrumentally recorded in the gulf south of 27 June 2015 swarm. The complete waveform and polarity data set of both two swarms recorded by the broadband and short period stations of ENSN were essentially analysed to determine type and geometry of faults and to update our knowledge in stress field of and the tectonic setting of Gulf of Aqaba. Through the obtained results, we were able to divide the Gulf of Aqaba tectonically into several segments each segment having different seismic characteristics than the other. The scientific truth that gathers all the gulf segments is that the fault segments are of a kind left lateral strike slip with minor normal component in some segments and minor reverse component in the other.

Keywords: Seismotectonic setting, earthquake swarms, Gulf of Aqaba, Egyptian National

Seismological Network (ENSN)

13

*Corresponding author Dahaoui Mohamed <[email protected]>

Poster: Active Tectonics, Paleoseismology and Historical Seismicity https://afsc2018.sciencesconf.org/192998/

S.01: SEISMICITY AND STRESS FIELD VARIATIONS IN RIF REGION & ALBORAN SEA FROM MAJOR SEISMIC CRISIS : 1960-2016.

Dahaoui Mohamed 1, Abdelouafi Abdellah 1, El Mahsani Abderrahman 1, Labraimi Ayoub 1

1 - Université Mohammed V (Morocco)

Abstract

This study is devoted to the analysis of the stress state along the Rif and the Alboran Sea region based on the inversion of focal solutions. For this reason, we have constructed a focals mechanisms solutions database containing 131 solutions. Part of it consist of a compilation of focal solutions built from P-wave polarities from available studies, by inversion of broadband seismograms, and CMT solutions. We have constructed the remaining by processing the first P-arrival onsets of aftershocks following large earthquakes, recorded and located by dense temporary seismic networks (Al Hoceima & Alboran Sea). These sequences of aftershocks cover distinct seismogenic zones along the study area and are consequently convenient for establish the stress field and its variation. The stress regime is generally strike-slip in the Moroccan Rift. At the level of the Alboran Sea, The focal mechanisms determined correspond to a strike-slip/normal/reverse motion in the western cluster and thrusting in the eastern one. Locally in Al Hoceima region, the most mechanisms correspond to normal and/or strike-slip faulting mainly. Shows that the main compressional axis.

Keywords: Stress tensor., Seismicity, Focal mechanism, Al Hoceima, Rif, Alboran sea,

Morocco

14

*Corresponding author Makkaoui Mohamed <[email protected]>


S.01: LA MORPHO-STRUCTURE DES FORMATIONS NEOGENE ET PLIO-QUATERNAIRES DU RIF ORIENTAL (MAROC)

Makkaoui Mohamed 1, Azzouz Omar 2

Abstract

Le Rif oriental est marqué par la présence de plusieurs bassins néogènes et plio-quaternaires cadrés par des terrains du mésozoïques qui se trouvent dans des zones en reliefs. Cette disposition s'inscrit dans des structurations en horsts et grabens relevant d'une succession de plusieurs phases de déformations tardi-orogéniques. Elle est déterminée par des déformations essentiellement cassantes animées par des recoupements complexes de plusieurs accidents régionaux. Cette étude a pour objectif de mettre en relief les limites géométriques de ces différents bassins et les mécanismes tectoniques qui ont régi leur différenciation, sur la base de l'apport des données de la cartographie numérique. Dans cette approche, nous avons procédé par une numérisation systématique des cartes géologiques et leur intégration dans un système d'informations géographique. Nous avons défini ainsi une superposition de plusieurs linéaments structuraux coïncidant avec les limites cartographiques des différentes formations néogènes et plio-quaternaires. Ces données ont été confrontées d'une part avec les linéaments majeurs définis par les ruptures morphologiques des reliefs, les réseaux hydrographiques et les traits de côtes. Elles ont été coïncidé d'autres part avec les représentions tridimensionnelles des données sismiques. Ce qui nous permet de vérifier l'ordre chronologique des différentes phases de recoupements et de superposition de ces structurations tectoniques récentes et actives.

Keywords: Bassin néogène, Cartographie numérique, Tectonique récente et active, Rif

oriental, Maroc.

15

*Corresponding author Kwadiba Tarzan <[email protected]>


S.01: UPDATED SEISMICITY OF BOTSWANA FOR THE PERIOD 1950?2017

Kwadiba Tarzan 1, Ntibinyane Onkgopotse 1, Mpuang Admore 1, Maritinkole Joseph 1

1 - Botswana Geoscience Institute (Botswana),

Abstract

Although Botswana is considered to be seismically quiet as it is located thousands of kilometres away from seismogenic tectonic plate boundaries in the surrounding oceans, a major earthquake could still occur under a heavily developed and populated area in the country. For example, Botswana and much of southern Africa were flummoxed by a magnitude 6.5 earthquake on the 3rd April 2017 that nucleated within the heart of the Kgalagadi Desert. Had this event occurred beneath Gaborone, Francistown or any of the densely populated areas of the country, the impact would have been unthinkably catastrophic. Therefore, it is necessary to carry out long-term monitoring of earthquakes to understand the spatial and temporal distribution of the local and regional seismicity, and to contribute in the assessment and mitigation of seismic hazards for the minimization of loss of human life, property damage, and social and economic disruption associated with the occurrence of earthquakes in Botswana and the surrounding area. To that end, an updated earthquake catalogue based on instrumental observations has been assembled for Botswana and the adjacent regions for the period 1950 and 2017. The target region is located within the area delineated by South Latitudes 17o and 28o and East Longitudes 19o and 30o. A better definition of the seismicity of Botswana is currently being achieved through deployment of a network of 21 state-of-the-art 3C broadband seismographic stations distributed across Botswana. The new stations comprise the Network of Autonomously Recording Stations (NARS)-Botswana project, which is being undertaken jointly by the Botswana Geoscience Institute and the Netherlands based University of Twente and Utrecht University over the period 2013-2018. The collaborative network will revitalize the use of earthquake seismology to investigate the earth structure beneath Botswana and to improve our knowledge the complex tectonics and seismicity regime in southern Africa.

Keywords: Seismicity, Earthquakes in Botswana, Mitigation of seismic hazards,

Instrumental observations

16

*Corresponding author Guessoum Nabila <[email protected]>


S.01: SOFT-SEDIMENT DEFORMATION STRUCTURES INDUCED BY EARTHQUAKES (SEISMITES) IN QUATERNARY DEPOSITS (WESTERN ORAN ,ALGERIA)

Guessoum Nabila 1, Benhammouche Azzeddine 1, Bouhadad Youcef 1

1 - Centre National De Recherche Appliquée En Génie Parasismique (Algeria)

Abstract

Western Oranie, is located in the Northwestern of Algeria, is the seat of a seismic activity where several earthquakes were occurred in the past. In this region, several deformation structures in soft sediments have been identified in Quaternary (Villafranchian to present) deposits. The Pleistocene marine terraces contain many Soft- sediment deformation structures (SSDS), mainly located a along the coast and even in the interior of the continent and also found in recent alluvium composed by sandy, silty and clayey sediments. Several outcrop sites have been encountered in this region. The Soft-Sediment Deformation Structures include: injection sand dykes, pillar structures, pillow structures, load-casts structures, water escape structures, sismoslump, thixotropic wedges and thixotropic bowls, all indicative of sediment liquefaction or fluidization. Many arguments supports their seismic origin , the presence of active faults able of producing strong earthquakes, the granulometric characteristics of the deposits are favorable to liquefaction and the observed features. Regional considerations favour that a recent tectonic activity were occurred in this area of Northwestern of Algeria as cause of the soft-sediment deformation structures.

Keywords: western Oranie, Quaternary deposits, earthquake, seismites, sediment

deformation, Soft, Algeria

17

*Corresponding author Ahmed Rezouk <[email protected]>


S.01: GEOMORPHIC, STRATIGRAPHY AND NEOTECTONICS IN THE HODNA BASIN (ALGERIA): CASE STUDY OF THE CHOTT EL HAMMAM STRUCTURE

Ahmed Rezouk 1, René Guiraud 2, Bouhadad Youcef 3, Jean François Ritz 4, Belhai Djelloul 5, Maouche Said 6, Kamel Amri 1

1 - Université des Sciences et de la Technologie Houari Boumediene [Alger] (Algeria), 2 - Geoscience Montpellier, Université Montpellier II (France), 3 - Youcef (Algeria), 4 - Geoscience Montpellier, Université Montpellier II, CNRS, UMR 5243 (France), 5 - Université des Sciences et de la Technologie Houari Boumedien, Laboratoire de Géodynamique, Géologie de l'Ingénieur et Planétologie (Algeria), 6 - Centre de Recherche en Astronomie, Astrophysique et Géophysique (Algeria)

Abstract

The studied area is located in the Hodna Neogene basin in the eastern Tell Atlas of Algeria. From a geological point of view, the Chott El Hammam consists of an ENE-WSW anticline. The folded series range from the Miocene to the Pliocene and are unconformably covered by alluvial terraces and Quaternary limestone encrusting on both sides. This work is two folds: 1)Performing a detailed map of the Miocene, Pliocene and Quaternary alluvial terraces and abandoned Quaternary surfaces; 2) Drawing topographical and geological cross-sections to determine the overall distribution of the morphological and lithological features in the studied area. For this purpose, a database was created to store the different kind of information (topographic maps, a Digital Elevation Model data of 30m and field structural and geomorphic measurements). The combination of different analyses (topographic, geologic, geomorphic) allowed us to constrain the Chott El Hammam fault and related folding and discuss the seismic activity of the studied area.

Keywords: Geomorphic, neotectonics, Hodna basin, Chott El Hammam

18

*Corresponding author Benamri Sofia <[email protected]>


S.01: THE ACHAKKAR QUATERNARY FM. SEISMITES (NORTHERN ATLANTIC COAST, MOROCCO): ARE THEY TRIGGERED BY RECENT SEISMOTECTONICS ACTIVITY

Benamri Sofia 1, Aboumaria Khadija 1, Aberkan M'hamed 2, Zaghloul Mohamed Najib 1

1 - Faculté des Sciences et Techniques de Tanger (Morocco), 2 - Faculty of Science Rabat (Morocco)

Abstract

The establishment of Quaternary deposits of the Tangiers peninsula, located at the north-western of the Rif chain, is controlled by a differential neotectonic essentially characterized by vertical movements of pliocene-quaternary age (Morel et al., 1987). The main factors triggering the syn- and late sedimentary structures recorded in the quaternary sediments of the Achakkar Formation and their relative interpretations can be the subject of several controversies (Aboumaria, 2009 ) namely: 1) a controlled liquefaction by the water content in sediments still loose during their gravitational sliding along an underwater slope. This will be at the origin of syn-sedimentary faults, hydroplastic folds, slymps / convolutes and "kelvin-Helmotz" type structures. 2) The gravitational process responsible for the entrainment of liquefied particles and the subsequent deformation of sediments would be triggered by a Seismicity probably related to earthquake and / or energy release along supra-structural fault planes during their tectonic activity.

Keywords: Neotectonics, Seismites., Sedimentary structures, Tangier Peninsula, Quaternary

19

*Corresponding author Salama Asem <[email protected]>,


S.01: SEISMOTECTONICS MAP OF NORTHERN EGYPT

Salama Asem 1, Meghraoui Mustapha 2, El Gabry Mohamed 1, Hussein Hesham 1, Korrat Ibrahim

3, Maouche Said 4

1 - NRIAG (Egypt), 2 - Institut de Physique du Globe (France), 3 - Mansoura University (Egypt), 4 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria)

Abstract

Seismotectonics study was investigated along the northern Egypt. Seismotectonoics map of northern Egypt are built up as first step of construction of seismotectonics map of Egypt. The geology, geomorphology, historical and instrumental seismicity, focal mechanisms, calculated stress inversion, and GPS data were used to identify the present day stress regime of the main active zones. The parameters of the present day stress tensor deduced from focal mechanisms data are calculated using the Tensor program version 5.8.6 of 23 November 2016 for the main six active zones. This method used as the Right Dihedron method and the Rotational Optimization method. The Rotational Optimization method has used in the determination of the four stress parameters, ?1, ?2, ?3 and stress ratio R = (?2 - ?3)/(?l - ?3); used the stress Tensor program to calculate these parameters (Delvaux and Sperner,1993). The main result is that the whole northern Egypt is considered as a part of the extensional regime except the Egyptian continental margin. 3 Layers of GIS database were constructed for the seismotectonics map of north Egypt using geology, geomorphology, historical and instrumental seismicity, focal mechanisms, calculated stress inversion, and GPS data.

Keywords: seismotectonics, active zones, northern Egypt, GIS database

20

*Corresponding author Djenba Samir <[email protected]>


S.01: THE SEISMES OF THE SÉTIF REGION, READING AND INTERPRETATION

Djenba Samir 1

1 - universite de batna (Algeria)

Abstract

La région de Sétif appartient, selon le RPA 2009, à une zone de moyenne sismicité. Historiquement cette région est frappée par plusieurs séismes de faible à fortes magnitudes (Les séismes de Tizi N'béchar 1924, Kherrata 1949, 1959 ; Ras El Oued 1953 ; Sétif1957 ; Maouan1958 ; Bir Hadada 1963,1968; El Mahdia 1967 ; El Ouricia 1975 ; Djemila avril-juin 1977 ; d'El Madher 1986 et Beni Ourtilène 2000). Les épicentres de ces séismes montrent une harmonie quasi parfaite avec les jeux de failles et aux contacts anormaux des nappes de charriage. Nous essayerons dans ce modeste travail faire une approche séismotectonique afin de relier ces séismes au contexte tectonique de la région et les régions limitrophes. Apriori on constate une nette jonction des épicentres aux contactes anormaux de dj.Youssef - dj Tella et celui des monts de Belezma. Un autre alignement des épicentres est observé le long d'Oued Bouselem de direction NW-SE qui laisse supposer une relation étroite de la sismicité de la région de Sétif avec le décrochement de dj.Bouarif plus au Sud (Nord Est de la ville de Batna). c'est approche basée sur la superposition des foyers des seismes sur les cartes et coupes géologiques compléte par des mesures des structures tectoniques actives sur le terrain.

Keywords: djebel Tella, siesme, Sétif, séisme, djebel Youssef

21

*Corresponding author Dib Assia <[email protected]>


S.01: SEISMICITY AND SEISMOTECTONIC OF THE AREA OF ALGAVRE (PORTUGAL)

Dib Assia 1, Bezzeghoud Mourad 2, Abdelhakim Ayadi 3, Mohamed Hamoudi 1 4, Oussadou Farida 3

1 - Université des Sciences et de la Technologie Houari Boumediene [Alger] (Algeria), 2 - Universidade de Évora Colégio Luís António Verney (Portugal), 3 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria), 4 - USTHB (Algeria)

Abstract

As part of this thesis, it comes to study the area of Algavre (South of Portugal) by microseismicity campaign in the context of the collision of African and Eurasian plates. This region has generated particular interest because it lies on the border of two tectonic plates which collide with an onshore and offshore seismicity. This study was carried out through a cooperation project between the University of Strasbourg (France) and the University of Evora (Portgal). The stations used and the financing of this campaign belong to the University of Strasbourg and the Portuguese telemetric monitoring network. In this study, there will be to do: data processing for more than a year and a half (seismic data obtained from two monitoring networks, the laptop and the other telemetric). Then, the picking phase, the construction of focal Mechanisms, location and relocation as well as seismic tomography for the determination of the velocity structure at the crust by inversion.

Keywords: Seismicity, tomography, location, tectonic

22

*Corresponding author Benbakhti Imene Meriem <[email protected]>


S.01: ACTIVE TECTONIC IN MEDITERANEAN COAST: NEW INSIGHTS FOR THE ARZEW SALINES, NORTHWEST ALGERIA

Benbakhti Imene Meriem 1, Maouche Said 2, Belhai Djelloul 3, Ritz Jean-François 4, Rabaï Ghilles 3

1 - Université des Sciences et de la Technologie Houari Boumedien, Laboratoire de Géodynamique, Géologie de l'Ingénieur et Planétologie (Algeria), 2 - Centre de Recherche en Astronomie, Astrophysique et Géophysique (Algeria), 3 - Université des Sciences et de la Technologie Houari Boumedien, Laboratoire de Géodynamique, Géologie de l'Ingénieur et Planétologie (Algeria), 4 - Géoscience Montpellier CNRS, Université Montpellier (France)

Abstract

The Tell Atlas trending belt is one of the most seismically active region in Northern Africa. Located in the western Mediterranean area, along the Africa?Eurasia convergent plate boundary, the Algerian coast displays evidences of active thrusting and coastal uplift associated with large earthquakes. The Mw 6.9, 21 May 2003 Zemmouri and Mw 7.3, 10 October 1980 El Asnam earthquakes were among the strongest events recorded in the area. The Oran basin, located in Northwest Algeria extends from Aïn Temouchent to Mostaganem, experiences a low to moderate seismicity. In this study, we focus on the Salines d'Arzew coastal area, which shows similitudes with seismogenic structures in northern Algeria (i.e Oued Fodda fault (El-Asnam) and the Sahel fold and related reverse fault near Algiers). The geological structures of Arzew Salines correspond to folds and reverse faults, affecting the quaternary formations. Although occurrences of obvious surface breaks have not been shown so far, morphotectonics features provide evidences of cumulative vertical movements associated with NW-SE shortening. They correspond to tilted deposits, and uplifted marine and/or alluvial terraces. These morphological features provide a reference and chronological data to constrain the coastal active tectonics in the Oran-Arzew region.

Keywords: NW Algeria, Arzew Salines, Active tectonics, Coastal zone

23

*Corresponding author Morad Taher <[email protected]>


S.01: L'UTILISATION D'UN IMEL POUR L'ÉTUDE LE MOUVEMENT DE LA FAILLE DE TROUGOUT - NORD EST DU RIF) MAROC) -

Morad Taher 1, Taoufik Mourabit 1

1 - Université Abdelmalek Essaadi (Morocco)

Abstract

A cause du risque sismique que connaît la région d'Al-Hoceima, de nombreuses études ont effectuées dans l'objectif de comprendre la sismicité, la sismotectonique et la géologie structurale, surtout après les derniers séismes de 1994 (Mw=5,4), de 2004 (Mw=6,3) et de 2016 (Mw=6,1). Pour améliorer l'évaluation du risque sismique et préciser la cartographie des failles actives qui affectent la région, diverses techniques et méthodes doivent être utilisées. Nous proposons l'utilisation d'un IMEL pour étudier et suivre le mouvement de la faille active de Trougout. Après quelques mois d'observation, les résultats ne sont pas encore significatifs et nous nous limiterons ici à la présentation de la méthodologie et l'état des lieux de la faille de Trougout.

Keywords: Faille deTrougout, IMEL, mesure le mouvement.

24

*Corresponding author Hassoup Awad <[email protected]>

Oral: Seismic source / Induced seismicity https://afsc2018.sciencesconf.org/199699/

S.02: ASWAN INDUCED SEISMICITY

Hassoup Awad 1

1 - National Research Institute of Astronomy and Geophysics [Helwan] (Egypt)

Abstract

The Aswan High Dam created the second man-made reservoir in the world (Lake Nasser) and is constructed near urban areas pose a high-risk potential for downstream life and property. It is located in an area occupied by faults dominant in the east?west and north?south trends. This area is seismically active in two seismic zones shallow and deep (i.e. between 0 and 14 and 14 and 30 km), respectively. They are characterized by different b-value, lateral extent and rate of seismicity as well as, spatial clustering. The temporal variation of this seismicity is correlated with the water level fluctuations in the lake. Moreover, it is swarm sequences. The effect of the North African drought (1982 to present) is clearly seen in the reservoir water level. As it decreased and left the most active fault segments uncovered, the shallow activity was found to be more sensitive to rapid discharging than to the filling. This study indicates that geology, lineations in seismicity, offsets in the faults, changes in fault trends and focal mechanisms are closely related. The peak ground acceleration is estimated in the dam site based on strong ground motion simulation. Recently, many moderated earthquake took place nearby the structure of the High Dam. This suggests that AHD dam must be analyzed with high priority and redesigned to increase the safety of the embankments and their appurtenant structures, if necessary.

Keywords: Induced Seismicity, Aswan, Egypt

25

*Corresponding author Andriamiranto Raveloson <[email protected]>


S.02: EARTHQUAKE LABORATORIES IN DEEP SOUTH AFRICAN MINES

Durrheim Raymond 1, Andriamiranto Raveloson 1 , Ogasawara Hiroshi 2, Manzi Musa 3, Yabe Yasuo 4, Onstott Tullis 5, Ziegler Martin 6, Ito Takatoshi 4, Liebenberg Bennie 7

1 - University of the Witwatersrand [Johannesburg] (South Africa), 2 - Ritsumeikan University (Japan), 3 - University of the Witwatersrand (South Africa), 4 - Tohoku University (Japan), 5 - Princeton Univesity (United States), 6 - ETH (Switzerland), 7 - Consultant (South Africa)

Abstract

It is extremely difficult to investigate the seismogenic zones of large earthquakes directly as they are often several kilometres deep and suitable drilling sites are rarely available. Consequently, there are many questions related to earthquake nucleation and rupture that remain unanswered. Some of the most important knowledge gaps are listed in the ICDP Scientific Plan (2014-2019). These include: (i) the physical properties that control rupture evolution and termination; (ii) the variation with time in physical properties in seismogenic zones and surroundings; (iii) the structural and physical differences between differently-sized earthquakes; and (iv) the fluid and chemical properties of faulting that influence microbiological communities. We also seek to explain the mechanism of the M5.5 Orkney earthquake, which took place on unknown geological structure below the mining horizon with a mechanism markedly different to typical mining-induced earthquakes. In 2017 we commenced an ICDP-funded project (DSeis) to drill into the source zones of M2.0-M5.5 earthquakes located 1-4 km below the surface in four deep South African gold mines. The drilling targets were previously characterised by a Japanese - South African collaborative research project (2009-2015). Cores with a total length of about 1.9 km have already been recovered, with minimal drilling-induced damage. We expect to complete the last ICDP-funded hole in March 2018. It will intersect the aftershock zone of a M5.5 earthquake beneath Moab Khotsong mine. Water and gas will be sampled in order to investigate whether deep microbial life is associated with seismic activity in any way. The DSeis cores are being logged, imaged, and catalogued using the ICDP DIS system. Stress is measured by analysing elastic anisotropic deformation of cores following drilling. Borehole geophysical logs and surface seismic reflection data are also available. A workshop will be held in late 2018 to determine the best rupture model for the M5.5 earthquake.

Keywords: earthquake, induced, gold mine, South Africa, rupture

26

*Corresponding author El Ouai Driss <[email protected]>


S.02: SEISMIC REFRACTION AND AMBIENT NOISE H/V SURVEYS TO INVESTIGATE AND REBUILD AN OLD BRIDGE, ACROSS GHIS RIVER LOCATED IN THE SEISMIC AREA OF AL HOCEIMA, NOTH MOROCCO

El Ouai Driss 1, Tadili Ben Aissa 2, Tadili Mehdi 2

1 - Laboratory of Geophysics and Natural Hazards, GEOPAC, Institut Scientifique, Université Mohammed V de Rabat (Morocco), 2 - Iservice Pro (Morocco)

Abstract

In this work, we investigate the geotechnical conditions to rebuild an old bridge, located in north of Morocco. This country is considered to be in a region with moderate seismicity. However, the country had suffered in the past from a couple of hazardous events (e.g., Agadir earthquake in 1960, and Al Hoceima one, 2004). The study area is located of about 40 km south of Al Hoceima city (north of Morocco). The aim of this work is to help the local authority decision makers to define technical specifications to rebuild a new bridge across Oued Ghis, replacing the old one with standard norms. Two geophysical surveys (seismic refraction profiling and ambient noise H/V ratios analyses) were carried out simultaneously in April 2017. Results from Refraction show profiles with three layers. 1 An upper layer with a low velocity (218 m/s) formed by loose lime-soil, with a maximum depth of 2.5 m, 2 a medium layer composed mainly by unconsolidated coarse conglomerate, with a velocity of 1187 m/s and a thickness varying laterally, with a maximum depth of about 14 m, and 3 a third layer, with the highest velocity (4124 m/s), representing the bed rocks. It is constituted by an alternation of green shales and sandstone, trending WNW-ESE, and dipping of 34° to 64° North-west. For results from ambient noise H/V ratios, they show that the dominant frequency of the site is about 4 Hz. This increases towards the north of the study area. With these results from refraction and ambient noise H/V ratios, we would recommend that pillars of the new bridge should have a height superior than the maximum thickness (14 m) of the loose layers (1&2). It is also worth to mention that construction should avoid sites to the north, where frequencies start to increase significantly.

Keywords: Seismic refraction, Ambient noise H/V, Oued Ghis, Al Hoceima, Morocco

27

*Corresponding author Abderrahman Elmahsani <[email protected]>


S.02: SEISMIC HAZARD AND NEW SEISMOGENIC ZONING IN THE STRAIT OF GIBRALTAR

Abderrahman Elmahsani 1, Ait Brahim Lahcen 1, Tadili Benaissa 2, Tlemcani Mohammed 1, Abdelouafi Abdallah 1, Lallout Imane 1, Dahaoui Mohammed 1

1 - Faculté des sciences [Rabat] (Morocco), 2 - Université Mohammed V, Institut scientifique Rabat, Unité de recherche LGRN (Morocco)

Abstract

The Rif chain is the result of the overlap of the thrust sheet over the northern part of Africa. This geodynamic context is governed by the collision of the African and Eurasian Cretaceous plates up to the present, this context is characterized by a complex tectonic activity, this gives rise to a seismic activity around the Mediterranean especially in the estern Mediterranean. This work aims to assess the seismic hazard in the Strait of Gibraltar by a probabilistic approach, based on a catalog of seismicity updated from several national and international agencies. We extracted the parameters of the Gutenberg-Richter law estimate, based on a new seismogenic zoning. The seismicity parameters thus determined, allowed us to realize the map of the maximum accelerations on the ground (PGA) for a return period of 50 years, by using the seismic hazard software CRISIS 2007. The maps thus obtained shows acceleration values that vary between 0.01g and 0.43g.

Keywords: Strait of Gibraltar, Seismic hazard, Gutenberg, Richter, PGA

28

*Corresponding author Khelif Mohamed Fadhlallah <[email protected]>


S.02: THE 2016 MIHOUB (NORTH-CENTRAL ALGERIA) EARTHQUAKE SEQUENCE: SEISMOLOGICAL AND TECTONIC ASPECTS

Khelif Mohamed Fadhlallah 1, Yelles-Chaouche Abdekrim 2, Benaissa Zahia 3

1 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria), 2 - Observatoire de Tamanrasset (Algeria), 3 - Université des Sciences et de la Technologie Houari Boumediene [Alger] (Algeria)

Abstract

On 28 May 2016 at 23:54 (UTC), an Mw5.4 earthquake struck Mihoub village, Algeria, 60 km southeast of Algiers. This earthquake was the largest event in a sequence recorded from 10 April to 15 July 2016. In addition to the permanent national network, a temporary network was installed in the epicentral region after this shock. Recorded event locations allow us to give a general overview of the sequence and reveal the existence of two main fault segments. The first segment, on which the first event in the sequence was located, is near-vertical and trends E?W. The second fault plane, on which the largest event of the sequence was located, dips to the southeast and strikes NE?SW. A total of 46 well-constrained focal mechanisms were calculated. The events located on the E?W-striking fault segment show mainly right-lateral strike-slip (strike N70°E, dip 77° to the SSE, rake 150°). The events located on the NE?SW-striking segment show mainly reverse faulting (strike N60°E, dip 70° to the SE, rake 130°). We calculated the static stress change caused by the first event (Md4.9) of the sequence; the result shows that the fault plane of the largest event in the sequence (Mw5.4) and most of the aftershocks occurred within an area of increased Coulomb stress. Moreover, using the focal mechanisms calculated in this work, we estimated the orientations of the main axes of the local stress tensor ellipsoid. The results confirm previous findings that the general stress field in this area shows orientations aligned NNW?SSE to NW?SE. The 2016 Mihoub earthquake sequence study thus improves our understanding of seismic hazard in north-central Algeria.

Keywords: earthquake sequence, algeria, coulomb stress, reverse fault

29

*Corresponding author Zulu Brian Sibonelo <[email protected]>


S.02: ASSESSMENT OF TEMPORAL VARIATION AND SPATIAL VARIATION OF RECURRENCE PARAMETERS IN THE GOLD MINING REGIONS OF SOUTH AFRICA

Zulu Brian Sibonelo 1 2, Midzi Vunganai 1 2, Manzunzu Brassnavy 1 2, Durrheim Raymond 1

1 - Council for Geoscience (South Africa), 2 - School of Geosciences, University of Witwatersrand (South Africa)

Abstract

The analysis of the seismicity recorded by the South African National Seismograph Network, Strategic Water Management Project and Mine Health and Safety Project in the northern rim of the Witwatersrand Basin of Gauteng Province, South Africa, shows that the recorded seismicity does not follow a Poisson distribution. The classical approach of seismic hazard analysis needs to be modified to account for temporal variation of recurrence parameters namely, a-value, b-value, Mc, and Mmax for all established seismic sources. The delineation of seismic source zones took into account both the spatial variation in completeness, as well as the spatial variance in the occurrence of seismicity. In order to assess these factors, the latitude and longitude of seismicity were plotted as a function of time. This resulted in establishment of four seismic sources, namely, Far West Rand (FWR), West Rand (WR), Central Rand (CR) and East Rand (ER). A change observed in the recorded seismicity for all zones is highly influenced by changes in monitoring capabilities as well as mining activity. Thus, in characterising the seismic zones, the time variation in seismicity was taken into consideration. Time-dependent seismic source recurrence parameters were calculated for each seismic source using various software packages and techniques suitable to each seismic source parameter. The mining activities are continuing in the FWR and WR whilst they have discontinued in the CR and ER. Hence the abandoned mines in CR and ER are now flooding resulting in induced events and thus recent increase in seismicity.

Keywords: Spatial variation, Recurrence parameters, Seismicity, Temporal variation

30

*Corresponding author Beldjoudi Hamoud <[email protected]>


S.02: REASSESSING THE RUPTURE PROCESS OF THE 2003 BOUMERDES-ZEMMOURI EARTHQUAKE (MW 6.8, NORTHERN ALGERIA) USING TELESEISMIC, STRONG MOTION, INSAR, GPS, AND COASTAL UPLIFT DATA

Beldjoudi Hamoud 1, Delouis Bertrand 2, Yelles Chaouche Abdelkrim 1, Kherroubi Abdelaziz 1

1 - Centre de recherche en astronomie astrophysique et géophysique (Algeria), 2 - Laboratoire Géoazur (France)

Abstract

The Boumerdes-Zemmouri earthquake occurred ~50 km East of Algiers on May 21, 2003, at 19h44 (UTC). It is the second strong earthquake that struck northern Algeria, after the El Asnam earthquake (Ms=7.3) on 10 October 1980. The Boumerdes-Zemmouri event was the subject of many studies, among which several focused on the seismic source The 2003 rupture developed below the coastal area, partly under the sea. Deverchère et al. (2005) described active structures offshore which may have been activated during the 2003 earthquake. The motivation of this work is mainly twofold; i) combine for the first time a most comprehensive set of data, including teleseismic, strong motion, GPS, InSAR, and coastal uplift, in order to constrain in the best possible way the rupture model; ii) explore for the first time the possible coseismic activation of faults described offshore in Deverchère et al. (2005). Mahsas et al. (2008) proposed that post-seismic slip inferred from GPS measurements occurred between 0 and 5 km depth near the top of the coseismic rupture.Therefore, constraining the slip distribution is a real challenge and combining the different datasets having complementary coverage is the best approach that we can undertake. In this study, we explore kinematic rupture models of increasing complexity, taking into account previously published models and structural complexities proposed in the previous studies. In order to define an optimal model, we will assess to which point model complexity is justified by the data. Indeed, most of the available data in the near source area provide only a partial coverage of the rupture zone. Therefore, constraining the slip distribution is a real challenge and combining the different datasets having complementary coverage is the best approach that we can undertake. Nonetheless, we expect that it will be particularly difficult to constrain the rupture on the farthest offshore area.

Keywords: rupture process, Boumerdes, Zemmouri, coastal uplift, geodetic data,

seimological data

31

*Corresponding author Boulanouar Abderrahim <[email protected]>


S.02: SPATIAL DISTRIBUTION OF ATTENUATION IN NORTHERN MOROCCO AND THEIR INTERPRETATION

Boulanouar Abderrahim 1, Harnafi Mimoun 1, Dobrynina Anna 2, Rahmouni Abdelaali 3

1 - Earth Science Department, Scientific Institute, Rabat, Morocco (Morocco), 2 - Institute of the Earth's Crust (Russia), 3 - Faculty of Science, Mohammed V University (Morocco)

Abstract

In the present study, we investigated the spatial distribution of attenuation based on the Coda wave of northern part Morocco. For this purpose, we analyzed sixty-six broadband events from local earthquakes which recorded by twenty-four stations deployed by the Scientific Institute of Rabat during 2008. Also, we selected five frequencies (0.75, 1.5,3,6 and 12Hz) and four lapse time windows (30s, 40, 50 and 60s). Then, the attenuation values are extracting by applying the back-scattering model proposed by Aki and Chouet (1975). Additionally, the spatial distribution maps of the attenuation of Coda wave for this region are generated. The maps describe the attenuation (inverse of quality factors) distribution in this area. We conclude that the region known several anomalies of Coda attenuation for all frequencies and all windows used, like Al Hoceim and Nador regions with high attenuation. This is due to due of the high seismic activity and the presence of many faults. They are also compared with the heat flow map for this study zone. Moreover, the attenuation of Coda wave decreases with increasing depth into the crust of this area. This last result is explained by the fact that the earth becomes homogeneous more one penetrates into the crust of this area. Finally, these results can be used not only for scientific research but also for practical field.

Keywords: Coda wave, Morocco, Al Hoceima, Seismic, Attenuation

32

*Corresponding author Caldeira Bento <[email protected]>

Poster: Seismic source / Induced seismicity https://afsc2018.sciencesconf.org/192965/

S.02: THE 2018, 15 JANUARY EARTHQUAKE, ARRAIOLOS (PORTUGAL, M=4.9): RESULTS FROM THE BROADBAND SEISMIC NETWORK DATA AND MACOSEISMIC SURVEY.

Caldeira Bento 1, Araújo A. Alexandre 2, Borges José 1, Fontiela Joao 3, Oliveira Rui 4, Wachilala Piedade 5 6, Bezzeghoud Mourad 7 8

1 - Institute of Earth Sciences and Physics Department- University of Evora and Department of Physics, ECT - University of Evora (Portugal), 2 - Institute of Earth Sciences - University of Evora and Department of Physics, ECT - University of Evora (Portugal), 3 - Institute of Earth Sciences - University of Evora (Portugal), 4 - University of Évora, Institute of Earth Sciences, Portugal (Portugal), 5 - Institute Superior of Education Science of the Huíla, Department of Nature Sciences, Huíla, Angola (Angola), 6 - University of Évora, Institute of Earth Sciences, IIFA, Portugal (Portugal), 7 - Universidad de Evora (Portugal), 8 - Institute of Earth Sciences and Science ant Thecnology School- University of Evora and Department of Physics, ECT - University of Evora (Portugal)

Abstract

On January 15, 2018, an M=4.9 earthquake, with epicenter north of Arraiolos, occurred. Although did not produced material or human damages, it was felt in great part of the Portuguese Continental territory, having aroused a great curiosity in the population. In the vicinity of the epicenter it reached intensity VI (Aldeia da Serra and S. Gregório), having been felt with intensity IV / V in the city of Évora, about 20km from the epicenter. In Lisbon, more than 100km away the epicenter, it was felt intensity III. The area where this earthquake occurred, although never it has produced an instrumental earthquake of this magnitude, was being observed by the scientific community for presenting an anomalous seismic activity in the regional context. The seismicity pattern in this area is usually organized by sequences, that seems to show two dynamics: 1) earthquake swarms without any relationship with any major event; 2) a main event followed by aftershocks. In any case, it is a superficial seismicity (H <7km) and of reduced magnitude (M <4). Although this seismicity occurs in a region cutted by numerous faults, located in the Évora Massif, near the Lower Tejo-Sado basin border, where two important geological structures, with geomorphological evidence of activity are stand out (S. Gregorio and Ciborro Faults), it's not possible yet to establish a direct link between this earthquake and any of these faults. Of the few focal mechanisms that exist from the earthquakes in this region, predominates the strike-slip type. In this work, we will describe the procedure followed by the Institute of Earth Sciences researchers immediately after the main shock, with regard the installation of a broadband seismic network for aftershocks monitoring, and a macroseismic inquest campaign. The preliminary results obtained with the data collected in these missions will be presented, namely, the aftershocks distribution, seismic source study, macroseismic distribution maps and attenuation model.

Keywords: Portugal Earthquakes, aftershocks monitoring, macroseismic data, seismic

source

33

*Corresponding author Chami Adel <[email protected]>


S.02: SÉQUENCE SISMIQUE DE LA RÉGION D'AÏN AZEL (SUD DE SÉTIF ) JANVIER-MAI 2015.

Chami Adel 1, Yelles-Chaouche Abdelkrim 1, Benaissa Zahia 2, Khelif Fadl-Allah Mohamed 1

1 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria), 2 - Université des Sciences et de la Technologie Houari Boumediene [Alger] (Algeria)

Abstract

La région Nord-Est de l'Algérie est marquée par une sismicité importante aussi bien historique (jusqu'à 1900) qu' instrumentale. Parmi les séismes historiques on peu citer celui de Djidjelli le 22/08/1856 de magnitude Ms=5,7 (±0,17) (Ambraseys, 1982) qui s'est produit en mer et a généré un tsunami (Yelles-Chaouche et al. 2009a.). Quant à la sismicité instrumentale, on peu citer le séisme de Constantine le 27/10/1985 M=6,0 ( Bounif et al. 1987) ou encore la séquence sismique qui a frappé en 2010 la région de Beni-Ilmane commençant par l'événement du 14/05 Md=5,2 suivie de deux autres événements de magnitudes égales Md=5,0 deux et neuf jours après le choc principale (Yelles-Chaouche et al. 2013). Au début de cette année 2015, une séquence sismique s'est déclenchée dans la région située entre Aïn Azel (W. Sétif) et Merouana (W. Batna). Celle-ci a débuté par l'événement du 21/01/2015 à 16:06 GMT (Md=3,1) et encore celui du 22/02/2015 à 9:48 GMT (Md=3,4). Cette séquence s'est ensuite poursuivie le 15 Mars à 11:22 GMT lorsque cette même localité a été frappé par un séisme de magnitude Md=4,5 et qui a causé plusieurs dégâts matériels. Le 17/03/2015 une autre secousse de magnitude Md=4,3 s'est produite. Un autre événement de magnitude Md=4,2 a été par la suite enregistré le 18/03/2015. Devant cette succession de secousses, un réseau de six stations sismologiques portables a été déployé dans la région afin de renforcer le dispositif de surveillance. C'est ainsi que ce réseau a enregistré une multitude d'autres événements de différentes magnitudes dont le plus important est celui qui a eu lieu le 21/03/2015 à 22:55 GMT de magnitude Md=5,0. Le réseau est resté en place jusqu'au 23/08/2015. Dans cette étude, nous présentons l'analyse des 250 premières répliques. Les mécanismes focaux des principaux événements nous montre une faille décrochante dextre de direction Est-Ouest.

Keywords: sismologie, relocalisation, hypoDD

34

*Corresponding author Wachilala Piedade <[email protected]>


S.02: BACKGROUND NOISE OF THE ALDEIA DA SERRA REGION, PORTUGAL ? FROM A TEMPORARY BROAD BAND NETWORK

Wachilala Piedade 1 2, Borges José 3 4, Caldeira Bento 3

1 - Institute Superior of Education Science of the Huíla, Department of Nature Sciences, Huíla, Angola (Angola), 2 - University of Évora, Institute of Earth Sciences, IIFA, Portugal (Portugal), 3 - University of Évora, Departament of Physics, Institute of Earth Sciences, Évora, Portugal (Portugal), 4 - University of Évora, Institute of Earth Sciences, IIFA, Évora, Portugal (Portugal)

Abstract

In this study, we analyse seismic background noise to assess the effect of noise based on the detectability of a temporary network constituted by DOCTAR (Deep Ocean Test Array), who have been deployed in a period between 2011 and 2012 in Portugal mainland, and the Évora permanent seismic station. To the DOCTAR NETWORK we associate the Évora permanent seismic station. This network is constituted by 14 digital broadband stations (14 CMG-3ESP and one STS2 sensors) with a flat response between the 60 sec to 50 Hz, 24-bit and 120s to 60Hz respectively. The temporary network was operated in continuous recording mode (three-components) in a region located in the north of the region of Évora, within a radius of about 30 km around the village of Aldeia da Serra, region in which there is an important seismic activity in the context of Portugal mainland. Using the data acquired, we developed in Matlab a Hyper Matrix called SPEC, with all the spectral analysis for each component/station. The data were organized by hour and Julian days of the year, where it is possible to select any frequency range, and any time of day and period of the year, and subsequently it was calculated the power spectral densities of background noise for each station/component and compare them with high-noise model and low-noise model of Peterson (1993). Power spectral density estimates show moderate noise levels for most stations falling within the high and low bounds of Peterson.

Keywords: Peterson models, power spectral density, broadband network, Aldeia da Serra

Region, Background noise, Portugal.

35

*Corresponding author Abacha Issam <[email protected]>


S.02: SOURCE PARAMETERS OF THE MAIN SEISMIC EVENTS IN THE NORTHEAST REGION OF ALGERIA

Abacha Issam 1, Boulahia Oualid 2, Yelles-Chaouche Abdelkarim 2, Bendjama Hichem 2

1 - Centre de Recherche en Astronomie, Astrophysique et Géophysique (Algeria), 2 - Centre de Recherche en Astronomie, Astrophysique et Géophysique (Algeria)

Abstract

Seismicity in the Northeast region of Algeria (Eastern Tellian Atlas) is intense of moderate to low magnitude. Recently several important events were occurs in this region such as, the 2010 Beni-Ilmane earthquake sequence, the 2012-2013 Bejaia earthquake sequence and the 2017 earthquake sequence along of the North Constantine fault. The 2010 Beni-Ilmane earthquake sequence was marked by the occurrence of three successive main shocks of equal magnitude (5?M?5.2). The source parameters of the eighteen major events (M ? 4) of this seismic sequence were estimated. The digital data used in this study was recorded by twelve Broadband stations of the Algerian permanent seismic network. The displacement spectra for P- and S-waves were analyzed with Brune's source model. The scaling relation between the seismic moment, the source radius and the stress drop indicates a decrease in stress drop and source radius with decreasing seismic moment. On November 28, 2012 an earthquake of magnitude 5.1 was occurred 07 km east of Bejaia city (offshore part). Six months later, an earthquake sequence of two main shocks (M=5.2 and 5.0) was also occurred in the region on May 2013. The aftershocks distribution of this earthquake sequence shows a cluster oriented NW?SE and of about 20 km length. The focal mechanisms of the three mains shocks show near vertical right-lateral strike-slip fault plane. In 4th and 5th March 2017, the north Constantine fault experienced a seismic sequence of magnitude (0.8?M?4.7). A set of 106 well located events distinguish three separate regions. One event in Roknia region, 90% of events clustered in Oum Toub region and eight diffuse earthquakes in Ain Bouziane town.

Keywords: Beni, Ilmane, source parameters, scaling laws, Tellian chain, focal mechanism

36

*Corresponding author Omar Khaled <[email protected]>


S.02: A STUDY ON THE RELATION BETWEEN RECENT INDUCED SEISMICITY AND WATER LEVEL IN THE NORTHWESTERN PART OF NASSER LAKE, ASWAN- EGYPT

Omar Khaled 1, Dahy Sayed 1, Al Amin Ezat 1

1 - National Research Institute of Astronomy and Geophysics [Helwan] (Egypt)

Abstract

The Nasser Lake is located in a region of very infrequent earthquake occurrence, as revealed by the 5000- year recorded history of Egypt. After seventeen years of filling of the Aswan High Dam Reservoir a long sequence of induced earthquakes began. The main shock, Ms = 5.6, occurred on November 14, 1981, preceded by several foreshocks and followed by large number of aftershocks. After 33 years, the seismic activity still persists, but it is substantially reduced in frequency and magnitude. The aim of this investigation is to study the influence of the reservoir on induced seismicity and determination of focal mechanism of some earthquakes that occurred in the northwestern part of the Aswan High Dam Reservoir. These investigations indicate that the seismic activity took place mainly along Kalabsha fault and small parallel segments and, there is a clustering of activity at Khor El- Ramla area about 40 km south west of the High Dam. In the period from 1982 to the end of 2014, seventy five earthquakes with magnitude 3.5 ? M < 4.0 and thirteen earthquakes with magnitude greater than or equal to 4.0 were occurred. Also it shows that these earthquakes occurred during both loading and unloading periods. This indicates that the influence of the reservoir itself does not produce earthquakes, and there is no direct relation between the change of the daily rate and the size of earthquakes. So it cannot be used as a tool for prediction in case of Aswan Reservoir confirming that it is a unique reservoir in its behavior. Composite focal mechanism for four different seismic zones west of Nasser Lake show strike slip faults with minor normal component. The P (pressure) and T (tension) stress axes are trending ESE-WNW and NNESSW respectively.

Keywords: earthquake occurrence, seismic zones, unloading periods

37

*Corresponding author Bouskri Ghizlane <[email protected]>


S.02: TRACKING SPATIOTEMPORAL VARIATIONS OF GROUND DEFORMATION AND SOURCE PARAMETERS ALONG SLOW CONVERGENT PLATE BOUNDARIES CASE OF FIGURE: NORTHERN MOROCCO (WESTERNMOST MEDITERRANEAN)

Bouskri Ghizlane 1 2, Ammar Abdellah 3 4, Timoulali Youssef 5, Azguet Roumaissae 6, Ouchen Ibrahim 7, El Fellah Younes 8, Harnafi Mimoun 6

1 - Université Mohammed V (Morocco), 2 - Seismic Waves and Earth Structure research unit, Scientific Institute, Rabat - Morocco (Morocco), 3 - Département de Géologie, Université Mohammed V, Faculté des Sciences (Morocco), 4 - Département de Géologie, Faculté des Sciences, Rabat - Morocco (Morocco), 5 - Département de Géologie, Scientific Institute, Rabat - Morocco (Morocco), 6 - Seismic Waves and Earth Structure research unit, Scientific Institute, Rabat - Morocco (Morocco), 7 - Institut de Combustion Aérothermique Réactivité et Environnement (ICARE), CNRST Orléan, France (Morocco), 8 - Energy and Farm Machinery Department, rural engineering, Institut agronomique et vétérinaire hassan II (Morocco)

Abstract

During the Tertiary to Quaternary, NW-SE multiphase compressive and shear regime of the Alpine belt induced the genesis of the Betic-Rif Mountains Ranges that surround the westernmost part of the Mediterranean Sea, which is referred to as the Gibraltar Arc. Juxtaposed and inter-imbricated thrust and fold structures have been developed among a Miocene paroxysmal compression due to African-Eurasian plates convergence that is active nowadays with a rate of 3-4 mm/y. The current geodynamical configuration is typified by an importantly frequent (average of >1350 earthquakes above magnitude 3 per year), shallow (15km to 100 km depth) and moderate (Mw<6) seismicity with rapid energy release pulses that trigger seismic moments reaching 6.8 1018 Nm/y. We exhibit the dominance of transpressive tectonics in this area that are concomitant to complex fault systems and floating blocks moving continuously with anarchic velocity rates. We also provide reasonable coseismic deformation models across the Gibraltar Arc as an illustrative figure case of critical active subduction. Waveform inversion and analysis of a set of 40 local earthquakes and aftershocks relocation to deduce coseismic displacement between 2010 and 2017, joint to seismic reflexion and swath bathymetry to reveal ground movements varieties and partake at filling heavy gaps, helping to establish the link between historical seismicity and recent tectonic movements. We suggest in this update to scrutinize the reliability of correlating the lateral changes of seismic stress to different geological/geophysical attributes i.e. faulting extent, aeromagnetic anomalies data and Coulomb's stress in a lesser degree. Our findings suggest, an en-echelon disposition of shallow-seated tilted blocks in parallel to the current shoreline, and the presence of loose soft sedimentary trenches beneath the Huceima and Nador cities, which plays a major amplificatory role and does not serve as favorable conditions for sufficient attenuating geometrical spreading of the propagated seismic waves, making shallow earthquakes more damaging to the affected agglomerations.

Keywords: Aeromagnetism, Seismic reflexion, Source parameters, Earthquakes, Subduction zone.

38

*Corresponding author Badreldin Hazem <[email protected]>


S.02: SEISMOTECTONIC MAP OF EGYPT

Badreldin Hazem 1

1 - National Research Institute of Astronomy and Geophysics (Egypt)

Abstract

The African continent is a stable region except the East African Rift, that through Mozambique, Kenya and Ethiopia. Consequently Egypt is bounded by three active tectonic plate margins; the African Eurasian plate margin, the Red Sea plate margin, and the Levant transform fault. Also the sub-plate of Sinai is a piece of African plate and separated by rifting along the Gulf of Suez. The main reason of the seismic activity in Egypt is the relative motion between African plate, Eurasian plate, and Arabian plate. In this paper all fault plane solutions that occurred in Egypt and its surroundings during the period from 1950 to 2017 to study the seismiotectonic setting of Egypt, seismiotectonic map of Egypt is not an easy task, due to many reasons (high azimuthal gap in some areas, distance from the source to station is too far and some earthquakes have small magnitude).several previous and ongoing studies provide outstanding results. Gulf of Aqaba gives normal faulting mechanism with minor strike slip component and their nodal planes trending N-S and WNW-ESE. Gulf of Suez shows normal faulting mechanism with small strike-slip component and their nodal planes trending NNW-SSE parallel to the gulf trend. Earthquakes in Dahshour zone show strike-slip faulting mechanism with slight normal component. Their nodal planes trend WNW-ESE and NW-SE. Red Sea show normal source mechanisms trending parallel to the rift. Aswan region shows strike-slip fault with minor normal component. Earthquakes located in the Mediterranean coast show revers faults.

Keywords: seismiotectonic, seismicity, fault plane solution

39

*Corresponding author Fontiela Joao <[email protected]>

Oral: Ground motion and site effects https://afsc2018.sciencesconf.org/192303/

S.03: STRUCTURE OF MITIDJA BASIN FROM HVSR

Fontiela Joao 1, Borges José 2, Ouyed Merzouk 3, Bezzeghoud Mourad 2, Idris Mouloud 3, Caldeira Bento 2, Salah Boughacha Mohamed 3 3, Carvalho Joao 4, Aissa Saoussen 3, Benfadda

Amar(3), Chimouni Redouane 3, Yalaoui Rafik 3, Dias Rui 5

1 - Institute of Earth Sciences - University of Evora (Portugal), 2 - Institute of Earth Sciences - University of Evora and Department of Physics, ECT - University of Evora (Portugal), 3 - Laboratoire de Géophysique, Faculté des Sciences de la Terre, de la Géographie et de l'Aménagement du Territoire (Algeria), 4 - Laboratorio Nacional de Energia e Geologia (Portugal), 5 - Institute of Earth Sciences - University of Evora and Department of Geology, ECT - University of Evora (Portugal)

Abstract

Mitidja Basin is located in N Algeria and it is filled with quaternary sediments. The S and N limits are active fault system of the reverse type with opposed dips which accommodate a general slip rate of ?4 mm/year. In the basin occurred earthquakes that caused severe damage and losses such as the ones of Algiers (1365, Io=X; 1716, Io=X) and the Bourmedes earthquake (Mw 6.9; May 2003). The event was caused by the reactivation of the MB boundary faults. The knowledge of the structure of the basin is limited to the surface layers (up to 200m) of the basin. Through the inversion of ambient seismic noise (also known as horizontal to the vertical spectral ratio (HVSR)), we evaluate the velocity and develop structural models of Mitidja basin. To acquire seismic noise were used broadband stations on a regular basis of 2.5km by 5.0 km (in lat and long, respectively), recording at least 60 minutes in each node. We acquired seismic noise on 150 points inside and at the edges of the basin. Through the horizontal to vertical spectral ratio, we identified frequencies lower than 1Hz which could be related to the transition of the quaternary sediments to the underlying rock. The structural model obtained from the inversion is calibrated through correlation of gravimetric data. This work is co-funded by the European Union through the European Fund of Regional Development, framed in COMPETE 2020 (Operational Competitiveness Programme and Internationalisation) through the ICT project (UID/GEO/04683/2013) with the reference POCI-01-0145-FEDER-007690 and by the bilateral project MITMOTION - Ground motion prediction in Mitidja Basin ? Alger(PT-DZ/0003/2015) and by the Thematic Agency for Research in Science and Technology (ATRST, Algeria, Project N° 03/2016).

Keywords: Mitidja basin, sedimentary basin, site effects, HVSR inversion

40

*Corresponding author Mohammed Touati <[email protected]>


S.03: TRAIN INDUCED WAVES PROPAGATION IN LAYERED SOIL

Mohammed Touati 1, Nezha Lamdouar 1, Ali Essahlaoui 2

1 - EMI, Civil Engineering department (Morocco), 2 - Moulay ISMAIL University, Meknes (Morocco)

Abstract

Train induced waves propagation in layered soil is the main topic to discuss other issues as the ground stability under railway loads, or the impact of such loads on buildings near railway tracks. The track irregularities impact indeed the magnitude of the loads communicated by the system train-track to those structures and may endanger their stability, especially if they are coupled to seismic loads. Therefore, the first issue is to model the train-track system. The simplest model that can be conceived in this regard is a mass supported by a spring-dashpoint unit. A two-dimensional model is obviously close to the reality when it concerns analyzing the vertical vibrations. However, if focus is to be extended to lateral vibrations which aren't to be neglected, a three dimensional analysis must be performed. The second aspect of our studies concerns the propagation of the railway loads on the ground in order to assess the frequencies and the amplitudes communicated to buildings. To do this, FEM will be performed on a semi-infinite layered ground as a numerical method of sumulation. The results of experimental investigation of the ground vibrations will be summarized like seismic refraction and H/V method. Finally, those two methods will be combined in order to provide a complete image of the shape and the size of the waves impacting structures and buildings near railway tracks, and dynamic behaviour of the soil itself.

Keywords: Train induced waves, Dynamic behaviour of a layered soil, Seismic refraction,

H/V method.

41

*Corresponding author Amponsah Paulina <[email protected]>


S.03: SEISMIC GROUND MOTION AND LAND USE PLANNING FOR THE GREATER ACCRA METROPOLITAN AREA, SOUTHEASTERN GHANA

Amponsah Paulina 1, Franco Vaccari 2, Panza Guliano 2

1 - Ghana Atomic Energy Commission (Ghana), 2 - University of Trieste (Italy)

Abstract

Records of damaging earthquakes in Ghana date as far back as 1615. Three major events occurred in 1862, 1906 and 1939. Current events registering more than magnitude 4.0 on the Richter scale have been recorded and the frequency at which they occur make the Greater Accra Metropolitan Area more prone to earthquake disaster than expected. The Greater Accra Metropolitan area has been modelled for land use planning and seismic disaster mitigation. The deterministic method, a hybrid method based on the modal summation and finite difference method was used to model the seismic ground motion of the metropolis. Using these techniques, the seismic ground motion along six profiles located in the Greater Accra Metropolitan Area was modelled. The 1939 earthquake of magnitude 6.5 (ML) was used as the scenario earthquake. Synthetic seismograms from which parameters for engineering design such as peak ground acceleration, velocity and spectral amplifications were produced along the geological cross sections. The seismic hazard of the Greater Accra Metropolitan Area, expressed in terms of peak ground acceleration and peak ground velocity were estimated from the seismograms computed. The low velocity formations (unconsolidated sediments) in the study area gave rise to the high peak ground acceleration and amplifications. The estimated peak ground acceleration and velocity would serve as a guide in structural and civil engineering design and construction in the Greater Accra Metropolitan Area.

Keywords: Seismic ground motion, Earthquakes, Greater Accra Metropolitan Area,

synthetic seismograms

42

*Corresponding author Maklad Mohamed <[email protected]>


S.03: ESTIMATION OF SHEAR WAVE VELOCITY PROFILES USING MICROTREMOR ARRAY EXPLORATIONS IN ISMAILIA CITY, EGYPT

Maklad Mohamed 1, Elgabry Mohamed 2, Yokoi Toshiaki 3, Hayashida Takumi 3, Hussein Hesham 2, Abdelfattah Tharwat 4

1 - National Research Institute of Astronomy and Geophysics [Helwan] (Egypt), 2 - National Research Institute of Astronomy and Geophysics [Helwan] (Egypt), 3 - International Institute of Seismology and Earthquake Engineering, Building Research Institute (Japan), 4 - Faculty of Science, Alexandria University (Egypt)

Abstract

Microtremor array explorations were performed at seven sites in Ismailia city, Egypt, to obtain 1-D Shear wave velocity (Vs) profiles. The Spatial Autocorrelation (SPAC) method was applied to the observed data for the determination of Rayleigh-wave phase velocity dispersion curves and estimation of Vs profiles. The estimated Vs profiles indicate that the maximum Vs values are around 500-700 m/s and the minimum Vs values are around 140-200 m/s. The calculated AVS30 values based on the estimated Vs profiles indicate that all the sites are categorized into site class C or D of Natural Earthquake Hazard Reduction Program (NEHRP) classification. The theoretical site amplification factors using Vs profiles show that the resonant frequencies for the sites located on the west side of Suez Canal range between 1 to 2 Hz, whereas they are lower than 1 Hz for the sites located on the east side.Microtremor horizontal-to-vertical spectral ratios (HVSR) were also calculated for all sensor records at each site. The derived HVSR show similar curves for all the sensors at each site, indicating nearly flat layered structure beneath each site. There are no clear HVSR peaks in the frequency range higher than 1 Hz, at which high S/N ratios were detected. We also calculated the theoretical HVSR of the fundamental mode Rayleigh wave and plotted them with the theoretical amplification factors. The dominant frequencies from both the theories are similar to each other at five sites. We tried to modify the Vs models for them, but the results show that the original Vs models are acceptable, since discrepancies between the observed and theoretical phase velocities are obvious except one site. Our results show that the combination of SPAC and HVSR methods is advantageous to support the results and can be a powerful tool for seismic microzonation studies and seismic hazard assessment.

Keywords: HVSR method, Theoretical HVSR, Site Amplification Factor, AVS30, SPAC

method, Ismailia City

43

*Corresponding author Mulabisana Thifhelimbilu <[email protected]>


S.03: LOCAL SITE EFFECTS STUDY BASED ON THE ORKNEY EARTHQUAKE OF 5 AUGUST 2014

Mulabisana Thifhelimbilu 1, Midzi Vunganai 2

1 - Council for Geoscience (South Africa), 2 - Council for Geoscience (South Africa)

Abstract

Site response analysis is conducted at 37 seismic stations in the region from KOSH to Johannesburg using the Nakamura, H/V spectral ratio technique on records of the Orkney 5th August 2014 earthquake. The earthquake of magnitude ML = 5.5, led to the unfortunate death of one person and damage of more than 600 houses. Intensity data collected soon after the event showed that the effects of the earthquake appeared to vary significantly across the North West and Gauteng region. This motivated the authors to conduct a more detailed investigation of the effects of site conditions on seismic station records in the region. Resonance frequency values obtained from the H/V ratios were observed to vary strongly across the region and also within clusters of ratios. A similar behaviour was observed with the amplitude of the ratios at the resonance frequency, except for the Johannesburg area whose results showed a relatively simple shape of the ratios implying less complex velocity structure. These results serve as a strong motivation or justification for the ongoing microzonation study of the Johannesburg and KOSH regions, where a detailed study of the velocity structure will be used to obtain reliable information on site amplification and resonance.

Keywords: Site Response, Waveform, Amplification

44

*Corresponding author Smailhodzic Hrustem <[email protected]>


S.03: FORMING OF LANDSLIDES AS A CONSEQUENCE OF SEISMIC ACTIVITY IN THE AREA OF BOSNIA AND HERZEGOVINA

Smailhodzic Hrustem 1

1 - Hrustem Smailhodzic (Bosnia and Herzegovina)

Abstract

Bosnia and Herzegovina is located in the central parts of the Dinaric mountain massif, and its position is northeast of the compression geotectonic contact between the Adriatic mass and the Dinarides. Adriatic microplate, as part of Africa, is compressed between Apennine and Dinaride along seismically active faults. Earthquakes that occurred in the territory of Bosnia and Herzegovina are related to the energy generated by the plating of the African plate under the European Board. With this submerging of the African under the European plate, a huge amount of energy is created, which is primarily tectonic energy, and it is liberated as energy through seismic allyactive faults. Released energy can be a trigger for landslide, sliding, Analysis of the occurrence of landslides to conclude that besides the landslide trigger can be the amount of water as a result of acid rain. The landslide was analyzed in the vicinity of the Zenica industrial center just after the earthquake.

Keywords: earthquake, landslide, seismic active faults, mountin impact, Mala Broda near

Zenica town, casualities, predisposed slopes

45

*Corresponding author Chaaraoui Aboubakr <[email protected]>


S.03: SITE-EFFECTS INVESTIGATION IN THE URBAN AREA OF NADOR TOWN (N-E MOROCCO), USING THE H/V TECHNIQUE

Chaaraoui Aboubakr 1, Chourak Mimoun 2, Peláez Jose 3

1 - Applied Geosciences Laboratory (Morocco), 2 - Mathematics and Mechanics Laboratory (Morocco), 3 - Department of Physics. (Spain)

Abstract

Local Seismic Hazard Assessment is an important research field in natural hazard studies. It relies on the determination of soil effects in a targeted area, which is the subject of this study. Also, the objective is to characterize soil in the urban area of Nador region, using ambient background noise (the H/V method). The fundamental period of different geological formations are calculated. The surface geology of the area consists of different lithological layers, mainly fluvial and marine sediments. Different geological layers of the subsoil, down to 30 m, are determined by interpretation of the different geotechnical surveys. In this study we performed 129 measurements, 1 hour each, using a seismograph with three-components. The values of the fundamental frequency vary between 0.20Hz and 4.2Hz. The Iso-frequency map has been developed afterwards. The results show that the values of the fundamental frequency vary according to the lithology of soil. Low values correspond to recent loose geological formations while high values correspond to the basaltic substratum. The results are an important tool for the development of the Seismic Risk Prevention Plan (PPR) on the one hand. On the other hand, it is a potential guide for preparing a city planning mitigation map.

Keywords: frequency map, Iso, fundamental soil frequency, H /V méthode, urban area of

Nador, PPR, city planning mitigation map.

46

*Corresponding author Ayad Abderrrahim <[email protected]>


S.03: STATIC CORRECTION FOR SEISMIC DATA ACQUIRED FROM BOUJDOUR AND TARFAYA-LAAYOUNE AREAS (SOUTH OF MOROCCO)

Ayad Abderrrahim 1, Bakkali Saad 1

1 - Faculty of Sciences and Techniques, Abdelmalek Essaadi University (Morocco)

Abstract

In Morocco, both the Tarfaya and Laayoune-Boujdour deposits are justifiably considered as a promising area of petroleum exploitation. These areas have been the subject of many seismic explorations in order to find structures favorable for the accumulation of petroleum and natural gas. In these sedimentary basins, the near-surface layers called weathered zone constitute a major challenge for the petroleum prospecting companies. These layers have low seismic velocity time compared with the velocity of the consolidated layers because they are poorly consolidated, in some cases coincident with a water table and therefore are a poor transmitter of seismic energy. In this work, the static correction method has been used to compensate the variations seismic-wave velocity time. This operation requires using the Shallow seismic reflection surveys and the Uphole method to assist in the determination of velocity and thickness variations of the weathered zone. The procedure involves establishing a datum on which to locate source and receiver, and then adding or subtracting the incremental time.

Keywords: Static Correction, Weathered Zone, Shallow seismic reflection, Upholes.

47

*Corresponding author Layadi Khalissa <[email protected]>

Poster: Ground motion and site effects https://afsc2018.sciencesconf.org/191942/

S.03: SITE-EFFECTS INVESTIGATION IN THE CITY OF CHLEF, ALGERIA, USING EARTHQUAKE AND AMBIENT VIBRATION DATA

Layadi Khalissa 1

1 - Centre de Recherche en Astronomie Astrophysique et Géophysique (CRAAG) (Algeria)

Abstract

Weak-motion recordings of local earthquakes and ambient vibration data in the 0.2?15 Hz frequency range were used to quantify site effects in downtown Chlef city, Algeria. Nine short-period stations were installed in the city. A total of 15 local events with 3:1 ? ML ? 4:9 were selected. Three experimental techniques were applied: standard spectral ratios, receiver functions, and horizontal-to-vertical spectral ratios using ambient vibrations (HVSRN). Theoretical HVSRN curves were also calculated from suggested soil models for each site. Fundamental frequencies obtained from all techniques showed good agreement. Two groups of fundamental frequencies were distinguished in the city. In the northern part of the study area, the frequency peaks varied from 0.3 to 0.4 Hz; in the southern part they varied from 0.6 to 1.6 Hz. The amplification factors of these frequency peaks were 4?8. Earthquake and ambient vibration data were able to identify fundamental frequency peaks successfully; however, the amplitudes of the peaks were slightly lower for ambient vibrations. Moreover, the fundamental frequency peak progressively increased from northwest to southeast, which is consistent with the direction of decreasing thickness of a Miocene layer overlying the basement. We infer, as expected, that the large impedance contrast between Miocene deposits and Mesozoic basement, which can be interpreted as seismic bedrock, is the cause of the fundamental frequency. Furthermore, earthquake data were more appropriate for identifying peaks at frequencies higher than the fundamental one. Indeed, a clear peak was observed at all northwestern sites in the 3?4 Hz range, with an amplification factor of 3?5. At the other sites, particularly in the center of the city, the peak was less evident.

Keywords: site effects, ambient vibrations, theoretical HVSRN curve, fundamental

frequency.

48

*Corresponding author Azguet Roumaissae <[email protected]>


S.03: ATTENUATION OF CODA WAVES IN SOUSS BASIN, MOROCCO

Azguet Roumaissae 1 2, Bouskri Ghizlane 1 2, Timoulali Youssef 3, Harnafi Mimoun 2, El Fellah Younes 4

1 - Seismic Waves and Earth Structure research unit, Scientific Institute, Rabat - Morocco (Morocco), 2 - Université Mohammed V (Morocco), 3 - Département de Géologie, Scientific Institute, Rabat - Morocco (Morocco), 4 - Energy and Farm Machinery Department, rural engineering, Institut agronomique et vétérinaire hassan II (Morocco)

Abstract

We investigate attenuation scattering and loss properties Souss basin (SW of High-Atlas) as a transition zone between the High and Anti Atlas ranges. This district consists in a thinned crustal patch with shallow seismicity and loose sedimentary trenches that perform an important contribution to augment seismic attenuation. So far, no coda waves approach in our knowledge has been used to draw satisfying outputs about the attenuation properties in the region. Therefore, this update suggests correlating the lateral changes of seismic attenuation to different characeristics and asperities i.e. seismic activity, crustal age and thickness, heat flow, and grinding deformation rate. To do so, we analyzed coda waves derived from waveform data of more than 23 local earthquakes from seven broadband seismometers recorded during 2010-2012 period. As a starter, we utilized the backscattering model which defines the seismic attenuation as inversely proportional to Quality factor by the equation (A=1?Q_c ). Q_c estimates were deducted at various central frequency bands 1.5, 3.0, 6.0, 9.0, 12.0 and 18.0 Hz according to different lapses times. The estimated average frequency dependence quality factor gives relation Q_c=120f^1,01 , while the average Q_c values vary from 149 at 1.5 Hz to 1895 at 18 Hz central frequencies. We observed an intimate dependence between quality factor and frequency ranges, which reflects the complexity of geological/geophysical pattern in the Souss basin and the presence of a variety of heterogeneities within the underlying crust.

Keywords: Souss basin, Frequency, Quality factor, Coda waves, Attenuation, Morocco

49

*Corresponding author El Fellah Younes <[email protected]>


S.03: SOIL AMPLIFICATION FACTORS AT THE SEISMOGRAPHIC NETWORK STATIONS SITES IN MOROCCO FROM SEISMIC AMBIENT NOISE

El Fellah Younes 1, Abd El-Aal Abd El-Aziz 2

1 - Energy and Farm Machinery Department, Rural Engineering; Institut Agronomique et Veterinaire Hassan II and Associated Researcher at Laboratory of Geophysics and Natural Hazards, Scientific Institute, University Med-V- (Morocco), 2 - Seismology Department, National Research Institute of Astronomy and Geophysics (Egypt)

Abstract

Abstract: Knowledge of the soil response to seismic activity allows to better incorporate the constraints of seismic risk reduction. The experimental methods employed to determine site effects seek to obtain seismic amplification parameters by means of measuring earthquakes or seismic background noise. In this work, we present the main set of results of the microtremor data analysis based on the horizontal-to-vertical (H/V) spectral ratio technique at broadband seismic stations in order to get the fundamental site frequency (f0) and its associated amplitude of ground motion (A0). These stations were deployed in different structural domains: Rif, Middle, High and Anti Atlas Mountains. This study was carried out using the Nakamura technique, based on the measurements of background noise at each measurement site. Nakamura's method makes it possible to evaluate the effect of the superficial layers on the seismic signal. The f0 (H\V) values were used in the calculation of bedrock depth at measured sites. The thickness of unconsolidated sediments at the investigated sites are determined. The parameters obtained in this work allowed us to highlight a set of distribution figures of fundamental frequency (f0), amplification (A0) (H/V) and soft sediments thickness throughout the location of study and to show the agreement with geological setting.

Keywords: H\V spectral ratio, amplification factor, frequency wavenumber, Thickness of

sediments

50

*Corresponding author El Moussaoui Said <[email protected]>

Oral: Tsunami hazard : data collection and modelling https://afsc2018.sciencesconf.org/195892/

S.04: HOW TIDE VARIATIONS CAN AFFECT THE TSUNAMI IMPACT ON A COASTAL AREA?

El Moussaoui Said 1, Omira Rachid 2, El Talibi Hajar 3, Aboumaria Khadija 1

1 - Faculté des Sciences et Techniques de Tanger (Morocco), 2 - Instituto de Portugues do Mar e da Atmosfera (Portugal), 3 - Faculty of Sciences and Techniques of Al Hoceima (Morocco)

Abstract

The Moroccan Atlantic coast, opened on the tsunamigenic zone of the Gulf of Cadiz, is one of the areas largely impacted by the AD 1755 tsunami. Previous works simulating tsunami propagation and inundation along the Moroccan coast has been carried out. However, only few studies have addressed the effects of tidal variations on tsunami coastal impact. In this study, the authors use numerical simulations to investigate how the tidal stage at the moment of the tsunami arrival can affect the tsunami characteristics (wave heights and run-in). Here, Assilah, one of the north Atlantic cities of the Moroccan coast that was hit by the 1755 tsunami waves, constitutes our case study. Tsunami simulations are conducted for four 1755-like earthquake scenarios, considering the two different phases of the tide (i.e. high and low levels). For a proper simulation of near-shore tsunami propagation and inundation, a high-resolution digital elevation model of Asilah is constructed. COMCOT (Cornell Multi-grid Coupled Tsunami Model) a validated open source program was used to model the source-to-coast tsunami processes. Results show that the tidal stage has a major effect on the maximum inundation distance experienced during a tsunami event. For instance, the maximum inundation limit at Asilah coast differs by more than 200m depending on the tidal phase. When the tsunami interacts with Low-tide level it produces a flood run-in of ~800 m along the Asilah coast. This value increases to about 900 m when the simulation is performed for high-tide stage. Thus, we recommend to model the tsunami hazard and vulnerability taking into account the tidal stage that can have a large effect on the predicted products, namely in coasts where tidal variations are significant.

Keywords: Morocco, Modelling, Tsunami impact, Tidal effect

51

*Corresponding author Benamri Sofia <[email protected]>


S.04: EVIDENCES OF AN EXTREME MARINE INUNDATION EVENT ON RABAT AREA ATLANTIC COAST (MOROCCO)

Benamri Sofia 1, Aboumaria Khadija 1, Zaghloul Mohammed Najib 1, Aberkan M'hamed 2, El Talibi Hajar 3, El Moussaoui Said 1

1 - Faculty of Science and Technology Tangier (Morocco), 2 - Faculty of Science Rabat (Morocco), 3 - Faculty of Science and Technology El Hoceima (Morocco)

Abstract

The sedimentological identification of deposits of extreme events such as storms is based on multidisciplinary experimental methods. The objective of the present study is to describe, characterize and identify the deposits generated by storms and to reduce the mechanisms involved in their formations as well as the factors that control their preservation. In the north-western coastal Meseta, the Rabat-Témara region has a coast of about twenty kilometers belonging to the Moroccan Atlantic coastline. The choice of this study area is based on three criteria: i) the coast of Témara is well known by storms hence its vulnerability, ii) its topography is very low not exceeding 200 meters, iii) it is a coastline exposed to the Atlantic Ocean that has experienced very historical extreme events for several centuries. After describing the regional stratigraphic and palaeogeographic context, we studied the paleoenvironmental significance of the storms based mainly on the sedimentological characteristics of the deposits, namely granulometric, mineralogical, morphoscopic, exoscopic and micropaleontological tests. We have also focused on the sedimentary patterns specific to these deposits, such as HCS structures (hummocky cross stratification), the structures of the current ripples to trace the vertical and lateral evolution of the tempestites by referring to the possible variations of the hydrodynamic regime and depth.

Keywords: Morocco., Temara, Rabat, Atlantic coast, sedimentological characteristics,

Tempestites

52



S.04: THE 1790 ORAN LARGE EARTHQUAKE (IO IX-X MKS) AND ITS IMPACT IN THE ALBORAN SEA: MODELING OF TSUNAMI WAVES AND CONSTRAINT OF SEISMIC SOURCE

Meghraoui Mustapha 1, Kariche Jugurtha 2 3, Aini Djamel 4

1 - Institut de Physique du Globe, CNRS-UMR 7516 (France), 2 - Université Houari Boumediene, Dept. of Geophysics (Algeria), 3 - IPG Strasbourg (France), 4 - Université de Mostaganem (Algeria)

Abstract

The 9 October 1790 earthquake generated severe damage in the Oran city (western Algeria) accompanied by a tsunami that affected coastal regions of the Alboran Sea. The mainshock occurred at around 1 am and the city was devastated as well as nearby villages. 22 aftershocks were felt the first day and the mainshock caused more than 4000 victims and a large number of injuries and homeless in NW Algeria. Oran was occupied by the Spanish in 1509 and freed following the seismic damage and destruction of the military fort, as well as due to the siege of the Algerian army (under the lead of Ben Osman, the Bey of Mascara region). The earthquake damage account has two main contemporary sources: 1) The Algerian chroniclers Ben El Bachir and Ben Sahnoun who report on the Oran city and surroundings from 1790 to 1792, and 2) from the Spanish reports under the authority of the local governor Cumbre-Hermosa. The earthquake caused damage in the major cities of Tlemcen, Mascara and Mostaganem and was clearly felt in Mellila, and in Almeria and Cartagena crossing the Alboran Sea. Some minutes after the mainshock, waves affected the Algerian, Moroccan and Spanish coastline, and inundations following sea retreat were observed in Oran, Mostaganem, Mellila, Almeria and Cartagena regions. Here, we test 3 seismic sources corresponding to coastal fault zones in the Oran region, estimate seismic moments and use NAMI DANCE program to generate tide gauges. The modelling of earthquake rupture is performed using an elastic half-space with homogeneous, uniform and isotropic properties (Okada, 1992). The obtained wave propagations and heights are compared to the tsunami characteristics and related coastal damage reports. This work is presented in the frame of EU-funded project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe).

Keywords: Tsunami, Algeria, modelling, seismic source, wave propagation

53

*Corresponding author Salama Asem <[email protected]>


S.04: TSUNAMI DEPOSITS AND HAZARD ALONG NORTH COAST OF EGYPT CORRELATE WITH HISTORICAL EARTHQUAKE RECORDS OF EASTERN MEDITERRANEAN

Salama Asem 1 2, Meghraoui Mustapha 2, El Gabry Mohamed 1, Maouche Said 3, Hussein Hesham 1, Korrat Ibrahim 4

1 - NRIAG, (Egypt), 2 - EOST (France), 3 - CRAAG, (Algeria), 4 - Mansoura University, (Egypt)

Abstract

Paleotsunami deposits and tsunami scenarios were investigated along the north coast of Egypt in the framework of the National Research Institute of Geophysics and Astronomy (NRIAG) and EC-Funded ASTARTE European tsunami and the French-Egyptian IMHOTEP projects. The study area located west of Alexandria is selected according to historical earthquakes and related inundation events as recorded in the archives. The two selected sites at Kefr Saber ?32-km west of Marsa Matruh city and ?10 km northwest of the El Alamein village are inner Laguna protected by 2 to 20-m-high dunes parallel to the shoreline. The two selected sites were chosen according to geomorphological and geological aspects. Five trenches and 12 cores were dug in two selected sites Kefr Saber and EL Alamein. X-ray scanning, magnetic susceptibility, grain size analysis, sampling and macrofossil detections, XRD analysis, total organic and inorganic matter measurements and carbon dating were carried out to identify the paleotsunami signatures. Tsunami scenarios were carried out for the most dangerous sources in east and west Hellenic arc. The high energy white sandy layer with rich in reworked fossils at Kefr Saber are correlated with 21 July 365 in Kefr Saber, while the four characteristic high energy sedimentary layers at the El Alamein site are correlated with the historical tsunami events of 1600 BC, 21 July 365, 8 August 1303, 24 June 1870. Our worst scenario for the Eastern Hellenic arc show that the initial wave is 33 minutes and the maximum wave heights ranging from 7-10 m at Kefr Saber & EL Alamein will be after 50 minutes. In case of the Western Hellenic scenario shows much longer 66 minutes' arrival time with a maximum wave height of 0.88 ? 1.76 m at Kefr Saber and 0.42-0.87 m wave height at El Alamein after 100 minutes.

Keywords: Paleotsunami, tsunami scenarios, northern Egypt

54

*Corresponding author Kherroubi Abdelaziz <[email protected]>


S.04: EVIDENCE OF TSUNIMAGENIC SOURCES ALONG THE ALGERIAN MARGIN

Kherroubi Abdelaziz 1, Yelles Chaouche Abdelkrim 2, Beldjoudi Hamoud 2

1 - Centre de recherche en Astronomie astrophysique et Géophysique (Algeria), 2 - centre de recherche en astronomie astrophysique et géophysique (Algeria)

Abstract

During its history, Algeria experienced some tsunamigenic events which remain rare as they are linked to the occurrence of strong coastal events (Yelles-Chaouche, 1991). Some reports mention a tsunami related to the destructive event of Algiers in 1365 (Ibn Khaldoun, 1369), the first well documented event remains the Djidjelli tsunami of August 21-22th 1856 (Rothé, 1950; Ambraseys,1982, Benhallou 1985). It had been triggered by a strong earthquake which hits the region at that time. During the recent (instrumental) period, two tsunamigenic events attracted our attention as they are the first ones recorded by instruments. The first recorded tsunami occurred after the El Asnam event of October 10th, 1980 Ms: 7.3. At that time, the earthquake, although 60 km away from the coast, has triggered a weak tsunami felt in the southeastern region of Spain (Soloviev et al., 1992, Benouar, 1994). The second tsunami, the more recent, is the tsunami of Boumerdes of May, 21st, 2003. This event, one of the most important in the western Mediterranean region for the last century, was generated by an earthquake of magnitude Mw=6.8 that occurred on the offshore reverse fault of Zemmouri (Yelles et al., 2003; Deverchere et al., 2005). Effects of this tsunami were felt in the whole western Mediterranean region and especially along the Balearic coasts (Alasset, 2006). The Boumerdes tsunami and the several recent marine investigations demonstrated for the first time the potential of the Algerian margin for tsunami generation.

Keywords: Tsunamigenic, earthquake, trigger, fault

55

*Corresponding author Korchy Hanan <[email protected]>


S.04: COULD THE DEPOSITS OF HIGH ENERGY ALONG THE IBERIAN AND MOROCCAN COASTS BE RELATED TO TSUNAMIGENIC EARTHQUAKES?

Korchy Hanan 1, Aberkan M'hamed 1, Benamri Sofia 2, Aboumaria Khadija 3, El Talibi Hajar 4, El Moussaoui Said 3, Zaghloul Mohamed Najib 3

1 - Faculty of sciences Rabat (Morocco), 2 - Faculty ofSciences and Techniques Tanger (Morocco), 3 - Faculty of Sciences and Techniques of Tangier (Morocco), 4 - Faculty of Sciences and Techniques of Al Hoceima (Morocco)

Abstract

Earthquakes have certainly always fascinated and frightened man since prehistory; their manifestation inland can cause civilian casualties and considerable economic damage (Sumatra, 2005). Nevertheless, generally, when a submarine earthquake occurs, with a magnitude over 7 on Richter scale, it can cause a tsunami. In case of vulnerability, this phenomenon can provoke great damage (Japan, 2011). That is why numerous researchers were conducted to understand the physical characteristics of tsunami wave and the sedimentological features of their deposits. This work aims to diagnostic and analyzes the evidence used by the authors to identify the high energetic deposits along the Atlantic coast of Morocco and the Iberian Peninsula, in order to determine if they are related to a tsunamigenic earthquake. In fact, along this coastal zone, numerous studies were established to distinguish high energetic deposits, attributed to storms or tsunamis. Most of those studies were based on calcarenite boulder's accumulation (Whelan and Kelletat, 2005; M'hammdi and al. 2008). Nevertheless, those accumulations alone cannot be considered as strong evidence for tsunami's occurrence. If the imbrication and the orientation of the boulders is a good criterion for tracing tsunamis origins, these boulders could have returned from their initial position during storms, posterior to a tsunami that might have deposed them (Harhoura), or may simply result from falling rocks resulting from erosion of the coastal cliff (Rabat, Temara, and on the Tangier coast.) It is therefore recommended to compare the accumulation and disposition of these boulders with other sedimentological signatures, such as the distribution of heavy minerals (El Talibi and al., 2016), exoscopic analysis (Bruzzi and Prone, 2000) and AMS (Magnetic Susceptibility Anisotropy) in order to reconstruct the sites affected by the manifestation of ancient tsunamis, in the perspectives to limit the risks caused by this hazard.

Keywords: Tempestites, Morocco, Atlantic Coast, Calcarenitic Boulders, Storms, Tsunamis,

Earthquakes, Tsunamites.

56

*Corresponding author Benchekroun Sabah <[email protected]>


S.04: TSUNAMI EVACUATION PLAN FOR TANGIER-MOROCCO BASED ON GIS TOOLS

Benchekroun Sabah 1

1 - Centre National pour la Recherche Scientifique et Technique (Morocco)

Abstract

Morocco is located in a convergence zone between two major plates, Eurasian and African ones. Given its situation, coastal Moroccan regions are prone to tsunami hazard due to large earthquakes that could occur in NE Atlantic ocean or Mediterranean basin . The rapid growth of population in coastal areas and the high evolution in touristic and economic infrastructures make these zones more vulnerable to tsunami hazard. This work proposes a method to choose the most effective evacuation routes using Geographic Information System (GIS) tools in a tsunami-prone area for Tangier city. Various GIS techniques and Network analysis were used to determine the suitable location of safe buildings and to draw the optimized routes for faster horizontal evacuation. For these purposes, some spatial information are required such as the distribution population at a local scale, the detailed road network and the location of shelters which can be used as refuges sites or assembly areas. The aim of this work is to provide practical support and tools to the local emergency services and useful information to assist risk managers in case of tsunami.

Keywords: tsunami, GIS tools, network analysis, evacuation plan.

57

*Corresponding author Fajri Zainab <[email protected]>

Poster: Tsunami hazard : data collection and modelling https://afsc2018.sciencesconf.org/191733/

S.04: CARTOGRAPHIE ET SIMULATION DES RISQUES NATURELS DU LITTORAL MAROCAIN : RÉSULTATS PRÉLIMINAIRES

Fajri Zainab 1, Aboumaria Khadija 1, El Talibi Hajar 2, El Moussaoui Said 1, Zaghloul Mohamed Najib 1

1 - Faculty of Sciences and Techniques of Tangier (Morocco), 2 - Faculty of Sciences and Techniques of Al Hoceima (Morocco)

Abstract

Les risques littoraux existent depuis toujours sur le littoral marocain. Des constructions de complexes touristiques, de résidences principales ou secondaires et des ports font de ces zones littorales un enjeu économique et naturel important, et de fait, vulnérables aux risques naturels. Provoqués par des séismes en milieu marin, les tsunamis sont souvent d'une violence particulière. Ravageurs, leurs dégâts dépassent de loin ceux provoqués par les séismes en terre ferme. Un méga tsunami des îles Canaries touchera non seulement les côtes atlantiques du Maroc, mais aussi l'Espagne, le Portugal, la Grande-Bretagne et même les côtes américaines. Cette étude vise à cartographier les zones à risques et l'évaluation de la vulnérabilité des structures et des installations le long des côtes atlantiques marocaines. Pour ce faire, nous avons dû digitaliser l'actuel trait de côte atlantique à partir des Images satellitaires, et reconstituer un modèle numérique de d'élévation à haute résolution qui servira de base pour toutes les simulations de catastrophe marine. Les résultats préliminaires obtenues, sont sous forme de carte de localisation des zones vulnérable aux risques naturels d'origine marine. Ces résultats montrent que les cotes Atlantiques du Maroc sont hautement vulnérables aux risques d'inondation d'origine Marine.

Keywords: Risque naturel, cartographie., Modélisation, Maroc

58

*Corresponding author El Talibi Hajar <[email protected]>


S.04: EVIDENCES OF AN EXTREME MARINE INUNDATION EVENT ON TANGIER COASTAL PLAIN ( MOROCCAN ATLANTIC COAST)

El Talibi Hajar 1, El Moussaoui Said 2, Aboumaria Khadija 2, Zaghloul Mohamed Najib 2, Wassmer Patrick 3, Mercier Jean-Luc 3

1 - Faculty of Sciences and Techniques of Al Hoceima (Morocco), 2 - Faculty of Sciences and Techniques of Tangier (Morocco), 3 - Faculté de Géographie et d'Aménagement (France)

Abstract

Extreme marine inundations (Tsunamis and storms) along Morocco's coasts have been described since historic times.The coastal sedimentary record, together with other proxies, is now being experienced to discriminate and reconstruct evidence of prehistoric inundation events. This paper aims to distinguishtsunami deposits in the sedimentary record by concentrating on the application of textural, morphoscopic, microtextural and compositional analysis, and reconstruct their likely source materials. This work presents results from Sidi Kacem coastal plain (Ain Guemmout area) where, the waves had run-up heights more than 9m and deposited boulders, shells, sand and lithic clasts. The heights reached by these waves and the dimensions of boulders transported along shoreline suggest that tsunamis rather than storm waves were the most probable wave form. The sampled stratigraphic section was composed of an upper sand and lower clay units. Typically, these unusual deposits displayed an abrupt basal contact, thinning and finning inland, massive structure and significant lateral variation. Distinction between tsunami and storm deposits was demonstrated by the amalgamation of rip-up clasts exclusively in the tsunamigenic deposits. Grain surface microtextural analysis evidenced to be a complementary procedure to be applied in the identification of extreme marine inundation deposits, particularly when considered within a regional context. Tsunami grains presented a recurrent existence of fresh surfaces and percussion marks once compared with possible source material. The heavy minerals content decreased up unit and in Sid Kacem, the assemblage presented resemblances with beach and coastal dune samples.

Keywords: Sedimentology, tsunami, grain size, heavy minerals, foraminifera

59

*Corresponding author Benhamouche Azzeddine <[email protected]>


S.04: THE PALEOTSUNAMI EVIDENCE AT THE LEVEL OF THE RABTA MARINE TERRACE IN THE JIJEL REGION (EAST ALGERIA)

Benhamouche Azzeddine 1

1 - CENTRE NATIONAL DE RECHERCHE APPLIQUEE EN GENIE PARASISMIQUE (Algeria)

Abstract

The Rabta marine terrace in the Jijel region which is a Phoenician necropolis is a rocky coastline subject to intense coastal dynamics and tectonics. It is characterized by the presence of boulders of variable sizes in preferential adrets. These block accumulations may have various origins: (a) erosion and alteration combined with gravity phenomena, (b) waves action generated by phenomenal storms in the Mediterranean or tsunamis, and (c) the combination of the two These block accumulations are distinguished by: 1 a similar lithology to the terrace deposits, 2 the imposing dimensions of some blocks (size and weight) which far exceed the ten tons, 3 the preferential orientation of the blocks elongation (the axis A is most often perpendicular to the shoreline 4 the imbrication of the blocks with respect one to other (overlapping), 5 the block polarity in normal or reverse position and 6the displacement index to the continent (striation and tectoglyphs). These criteria indicate a high energy signature. This wave type can be generated by phenomenal storms and tsunamis. According to the Atlas of winds and waves in the Mediterranean (2004), waves of storm which can achieve 20m of height are unlikely. Tsunamis waves of seismic origin whose mean height is less than or equal to 5m are more plausible The occurrence of this phenomenon is attested by the historical data (tsunamis of Jijel generated by the earthquakes of 21st and 22nd August 1856). The recurrence of this phenomenon is proved by the paleontological criteria identified in the paleosol and goes back to the certain Eutyrrhenian or probable Neotyrrhenian. Two periods of palaeotunamis can be distinguished: ante-phoenician paleotsunamis and post-Phoenician paleotsunamis without determining the number of events corresponding to each period. Nevertheless one of the post-Phoenician events is the 1856 tsunami that ravaged the Jijel city.

Keywords: Wave, Boulders, Marine Terrace, East Algeria, Jijel region, Paleotsunami

60

*Corresponding author Raveloson Andriamiranto <[email protected]>

Oral: Earth structures in Africa / The East African Rift System https://afsc2018.sciencesconf.org/190993/

S.05: SEISMIC STRUCTURE OF THE SOUTHERN PART OF MADAGASCAR AS REVEALED BY WAVEFORM MODELING

Raveloson Andriamiranto 1, Durrheim Raymond 1, Rindraharisaona Elisa 2

1 - University of the Witwatersrand [Johannesburg] (South Africa), 2 - German Research Centre for Geosciences - Helmholtz-Centre Potsdam (Germany)

Abstract

Once located in the center of the Gondwana supercontinent, Madagascar comprises crustal fragments from both East and West Gondwana. The crust and uppermost mantle structure of the southern part of Madagascar, possibly retaining the imprint of multiphase tectonic deformations, was investigated using the waveform modeling technique. This method was applied to the seismograms of the moderately large earthquake (MW=4.9) that occurred on 25th January 2013. Its epicenter is located offshore the southwestern coast of Madagascar near the town of Toliara. This earthquake was observed not only by the seismic stations installed in Madagascar, but by the regional seismic network as well. In this study seismograms recorded by the 25 temporary broadband seismic stations, installed along a direction nearly perpendicular to the Ranontsara shear zone during the SELASOMA experiment (2012 - 2014), were used. Synthetic seismograms are computed using the reflectivity method with a 4-layer crust over a mantle in half-space. The best fit between synthetic waveforms and observed seismograms is obtained by using a full-grid search approach. Results indicate that the crustal thickness ranges from 27.5 km to 39 km and the presence of a sedimentary basin with low velocities in the west.

Keywords: Waveform Modelling, Crustal Structure, Gondwana, Madagascar

61

*Corresponding author Faried Ahmad M. <[email protected]>


S.05: THREE DIMENSIONAL TOMOGRAPHIC IMAGE OF THE TRIPLE JUNCTION AREA, NORTHEAST OF EGYPT

Faried Ahmad M. 1, Hosny Ahmed 2 1, Farouk Mohamed 3

1 - National Research Institute of Astronomy and Geophysics [Helwan] (Egypt), 2 - National Research Institute of Astronomy and Geophysics (Egypt), 3 - King Abdullah University of Science and Technology (Saudi Arabia)

Abstract

To investigate the crust and uppermost mantle structure in the northern Red Sea region, where Gulf of Suez intersects with Gulf of Aqaba, we applied seismic tomography utilizing relocated local and regional earthquakes recorded by the Egyptian National seismic network (ENSN) and Saudi seismic network (SSN). P, S wave velocities anomalies and Vp/Vs ratio are obtained to reveal the current tectonic regime and the composition of the crust in the region. The synthetic tests (checkerboard test) applied to assess the ability to resolve reliable structural details in the earth. Our preliminary results differ with other previous works; Beneath the Gulf of Suez, at depths from 3-6 km, low P and S wave velocity anomalies have been observed with high Vp/Vs ratio, which may indicate the rocks saturated by hydrocarbon (oil), where most of the production Wells are existed. At depth from 6 to 15 km, low velocity anomalies with high Vp/Vs ratio in the middle part of the Gulf which reveal the active faults associated with most of seismic activity. Moho depth detected at depth 25 km, since high P and S velocity anomalies are seen. In northern red Sea, low velocity anomalies detected from depth 3 to 10 km which may reveal the intersection area between the transform movement of the Gulf of Aqaba and the extension of the Gulf of Suez, where most of the seismic activities are clustered. The Moho depth is detected at 10-15 km. In the middle part of Sinai Peninsula, low P and S wave velocity anomalies are noticed with a thickness of ~2-3 km, which indicate the sedimentary cover. High P and S wave velocity at depth of 32-34 km, which delineate the Moho interface. This study provided constraints on event locations and velocity models.

Keywords: relocation tomography, 3D, velocity model, crustal structure, oil potentiality,

magma seismicity

62

*Corresponding author Rekik Dhouha <[email protected]>


S.05: CONTRIBUTION OF THE RECEIVER FUNCTION METHOD IN THE VALIDATION OF THE SEISMIC DISCONTINUITIES MODEL IN TUNISIAN AREA

Rekik Dhouha 1, Ksentini Ahmed 2, Abbes Chedly 3

1 - Ph.D. student (Tunisia), 2 - assistant professor (Tunisia), 3 - professor (Tunisia)

Abstract

Twenty-two far earthquakes recorded by the seismic station '' Tamr '', located in north-western Tunisia, were processed using receiver function inversion method in order to determine the depth of Mohorovich discontinuity which separates the crust from the upper mantle. Through the seismic station ''Tamr '', the velocity profile was computed using the Seismic Analysis Code (SAC) in order to get more information about the depth of the Mohorovich seismic discontinuity. Visual inspection of the S wave velocity profile shows a discontinuity located at a depth of about 20 km under TAMR station.H-K stacking approach is planned in future works to best define the discontinuity using Vp/Vs versus depth plots. A Comparison between the results realized from Geotraverse project and those carried out in the current study was conducted to validate the seismological model of seismic discontinuity under the site.

Keywords: seismic stations, wave propagation velocity model, discontinuities, receiver

functions, SAC: seismic analysis code.

63

*Corresponding author Hosny Ahmed <[email protected]>


S.05: THINNING CRUST WITH HIGH VP/VS RATIO BENEATH THE ABOU DABBAB AREA, SOUTHEAST OF EGYPT.

Hosny Ahmed 1 2

1 - National Research Institute of Astronomy and Geophysics (Egypt), 2 - National Research Institute of Astronomy and Geophysics (Egypt)

Abstract

In this research, the physical properties of the crust under the Abou Dabbab region have been investigated by obtaining the receiver functions. The obtained results revealed thinning crust of 26-27 km thickness and vp/vs ratio of 1.88. The average crustal thicknesses beneath other regions of Egypt range from 32 to 38 km. The observed thinning eflects the effect of the red sea rift system, where modification for the crust has been done. The observed average vp/vs ratio of the crust is considered relatively high compared to the near region areas, Hurghada, and Mars Alam areas. This high ratio reflects the effect of a combination of regional stresses and local stresses. The regional is due to the Red Sea rift system, where heat could disseminate through lateral faults linked the crust of the study area with the red sea rift axes. While the local stresses could be related to some magmatic activity existed in the uppermost mantle. This magmatic activity has no yet reached to the surface as a volcanic activity. Another possibility to explain that high vp/vs ratio, that is due to the existing of the serpentine rocks in the crust which characterized by low shear wave velocity. In regarding to crustal thinning, the obtained results are consistent with many other previous studies conducted on the same study area. Additional geophysical measurements, such as computing the heat flow to confirm if thermal or igneous activity could be the reason of this high vp/vs ratio and the frequent earthquake swarms occurred in the study area.

Keywords: southeast of Egypt, Abou Dabbab area, High Vp/Vs ratio

64

*Corresponding author Midzi Vunganai <[email protected]>


S.05: INVESTIGATION OF THE 2017 BOTSWANA M6.5 EARTHQUAKE AND ITS AFTERSHOCKS

Midzi Vunganai 1, Saunders Ian 1, Manzunzu Brassnavy 1, Kwadiba Tarzan 2, Jele Vincent 1, Mantsha Reuben 1, Marimira Kwangwari 3, Mulabisana Thifhelimbilu 1, Ntibinyane

Onkgopotse 2, Pule Tebogo 1, Rathod Ganesh 1, Sitali Mako 4, Tabane Leonard 1, Van Aswegen Gerhard 1, Zulu Brian 1

1 - Council for Geoscience (South Africa), 2 - Botswana Geoscience Institute (Botswana), 3 - Zimbabwe Meteorological Services (Zimbabwe), 4 - Namibia Geological Survey (Namibia)

Abstract

An earthquake of magnitude M6.5 occurred on 3 April 2017 in Central Botswana. The event was well recorded and was located by the Council for Geoscience (CGS). In response to this event, the CGS, together with the Botswana Geoscience Institute (BGI), embarked on two scientific projects. The first involved the quick installation of a temporary network of six seismograph stations in and around the main event with the purpose of recording its aftershocks over a period of 3 months. Data recorded were collected and analysed using the SEISAN software and more than 500 aftershocks were identified in the first month and located in two clusters near the location of the main event. Given that the larger aftershocks were well recorded by the temporary network as well as the regional network of stations including the Botswana and South African National networks, the possibility of identifying ground truth events in the aftershock sequence is high. An effort was therefore made to collaborate with the Botswana Geoscience Institute to identify such events which will be of vital use in improving travel time curves and regional velocity models. The second scientific project involved a macroseismic survey to study the extent and nature of the effects of the event in southern Africa. This involved collaboration between CGS, BGI, Department of Meteorological Services, Zimbabwe and the Geological Survey of Namibia scientists. A total of 181 questionnaires were obtained through interviews and 141 online, which were analysed to produce 76 intensity data points, with maximum intensity values of VI (according to the Modified Mercalli Intensity scale) observed near the epicenter.

Keywords: Botswana, earthquake, seismograph stations, aftershocks, Ground Truth Events,

intensity, macroseismic.

65

*Corresponding author Ntibinyane Onkgopotse <[email protected]>

Poster: Earth structures in Africa / The East African Rift System https://afsc2018.sciencesconf.org/191998/

S.05: RECENT SEISMICITY (2014- 2017) OF THE OKAVANGO DELTA REGION: CONTRIBUTION OF BOTSWANA'S SEISMIC NETWORK

Ntibinyane Onkgopotse 1, Kwadiba Tarzan 1, Tladi Bruno 1, Mpuang Admore 1, Van Wettum Arie 2, Van Der Meijde Mark 3

1 - Botswana Geoscience Institute (Botswana), 2 - Utrecht University [Utrecht] (Netherlands), 3 - University of Twente [Netherlands] (Netherlands)

Abstract

The Okavango delta of northwestern Botswana is one of the largest alluvial fans on earth, and is hosted in a graben structure that forms the terminus of a southwesterly extension of the East African Rift System or EARS. The delta comprises the upstream panhandle and the downstream mega-fan situated in the middle of the Kalahari Basin. The Okavango Delta Region (ODR) has been observed to be characterized by the highest level of seismicity compared with other regions of Botswana. Data from the on-line bulletin of the International Seismological Centre (ISC) shows that many of the seismic events in the ODR have been detected by distant seismic stations at distances beyond 500 km from the heart of the delta, thus resulting in relatively poor location determinations. Here we present the results based on the data recorded by seismic stations deployed in the Network of Autonomously Recording Stations (NARS)-Botswana Project undertaken jointly by the Botswana Geoscience Institute and the Netherlands based University of Twente and Utrecht University. The NARS network consists of 21 three-component broadband seismographic stations distributed across Botswana to investigate the earth structure beneath Botswana, and to obtain a better understanding of its complex tectonics and seismicity regime. The new stations constitute part of the Botswana Seismological Network (BSN), in addition to the LBTB station near Lobatse and the MAUA station in Maun belonging to the global International Monitoring System (IMS) and the continental AfricaArray (AA) networks, respectively. The network coverage allows for a better definition of the regional seismicity of Botswana and accurate computation of magnitude, focal mechanism and improved understanding of the nature of causative faults in the region.

Keywords: Botswana, Okavango Delta, NARS, regional seismicity, Seismic Stations

66

*Corresponding author Kadiri Umar <[email protected]>


S.05: ASSESSING CTBTO'S DATA AND PRODUCTS FOR EARTHQUAKES RELOCATION AND IMPROVEMENT OF VELOCITY MODEL IN SUB-SAHARAN AFRICAN

Kadiri Umar 1, Ezomo Friday 2, Yakubu Tahir 3

1 - National Space Research and Development Agency. Centre for Geodesy and Geodynamics (Nigeria), 2 - University of Benin (Nigeria), 3 - Centre for Geodesy and Geodynamics (Nigeria)

Abstract

Knowledge of a reliable velocity model in a region is very key for researchers, especially, the seismological community. However, existence of a broad velocity model continues to elude substantial parts of sub-Saharan Africa resulting in poor earthquake locations, with attendant challenges in reliable seismological studies. Lack of well-defined velocity model in the region is occasioned by poor network of seismic stations, dearth of data, lack of requisite skills and capacity of a critical pool of African geoscientists to undertake robust studies to improve existing velocity models etc.Although desired results were not achieved, concerted attempts had been made in the past to improve velocity models in parts of West Africa and wider environs using tomography and Receiver Function techniques as documented in this work. In this study therefore: 1 the Regional Seismic Travel Times (RSTT) and iloc in Geotool software have been used to relocate a number of earthquakes in parts of Sub-Saharan Africa; 2 identification and contribution of prospective Ground Truth candidate events to improve RSTT model in the region. The results have shown significant improvements in events location compared to previous epicenters from other velocity models; and a clearer seismicity, seismic hazard and seismotectonics scenarios. It is expected this effort will enhance events characterization like earthquakes, chemical and nuclear explosions, for the benefit of verification of compliance with the CTBT, Seismic Hazard Assessment and Seismotectonic studies, mining activities, other seismological studies like the Inversion for earth structure etc. in the study area.

Keywords: Velocity model, Sub, Saharan Africa, Research Constraints, RSTT, verification

with CTBT, SHA

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*Corresponding author Chindandali Patrick R.n. <[email protected]>


S.05: ACTIVE INTRABASIN FAULTING IN THE NORTHERN BASIN OF LAKE MALAWI FROM SEISMIC REFLECTION DATA

Chindandali Patrick R.n. 1

1 - Geological Survey of Malawi (Malawi)

Abstract

Many questions remain about the development and evolution of fault systems in weakly extended rifts, particularly the relative roles of border faults and intrabasin faults in accommodating extension and variations in faulting along strike within and between rift segments and with time. The northern Lake Malawi (Nyasa) rift in the East African Rift System is an early stage rift exhibiting pronounced tectonic segmentation, which is defined by ~100-km-long border faults. The basins also contain a series of intrabasinal faults and associated synrift sediments. The occurrence of the 2009 Karonga Earthquake Sequence on one of these intrabasinal faults indicates that some of them are active. Here we present new multichannel seismic reflection data from the Northern Basin of the Malawi Rift collected in 2015 as a part of the SEGMeNT (Study of Extension and maGmatism in Malawi aNd Tanzania) project that constrain cumulative faulting patterns and recent activity on some intrabasin faults.

Keywords: Early stage rifting, Malawi rift, Multi, channel reflection, Northern Lake Malawi

68

*Corresponding author Marimira Kwangwari <[email protected]>


S.05: PRECISE STUDY OF THE 2009-2010, KARONGA EARTHQUAKE SWARMS

Marimira Kwangwari 1, Shumba Blessing 2, Mphepo Felix 3

1 - Meteorological Services Department (Zimbabwe), 2 - International Seismological Centre (United Kingdom), 3 - Geological Survey Department (Malawi)

Abstract

The study was carried out to understand earthquake occurrence in Karonga. The occurrence of the 5.8 earthquake and its subsequent well recorded aftershocks provided data to carry focal mechanism and to study the physics of earthquakes with the Karonga area. About 300 aftershocks after the 6th December Karonga earthquake were analysed as the aftershocks spans from 6th December 2009 to June 30th 2010. The earthquakes were recorded by a dense network of close stations provided by Africa Array and also by the 5 broadband seismic stations https://doi.org/10.7914/SN/YI_2010. In total there were 806 earthquakes within the study area which lies within latitudes 9.50°S and 10.60°S and longitudes 33.50°E and 34.60°E. Out of these 806 earthquakes; 468, 312 and 26 earthquakes were of magnitude ?M3.0 to ? 3.99; ?M4.0 to ? 4.99 and ?M5.0 to ? 5.99 respectively. Malawi has experienced earthquakes for the past decades, the 6.0 magnitude Karonga earthquake of 2009 being the largest ones in the history of Malawi's seismicity.

Keywords: Malawi, Karonga, Aftershocks

69

*Corresponding author Cherif Seif Eddine <[email protected]>

Oral: GIS and Risk Scenario https://afsc2018.sciencesconf.org/205016/

S.06: SEISMIC EVALUATION OF EXISTING RC BUILDINGS IN AL HOCEIMA AND IMZOUREN USING THE SEISMIC INDEX METHOD

Cherif Seif Eddine 1, Chourak Mimoun 2, Nobuoto Nojima 3, Abed Mohamed 4

1 - LSI Laboratory, CITRS, ESTEM, (Morocco), 2 - National School of Applied Sciences of Oujda, Mohammed First University (Morocco), 3 - University of Gifu, (Japan), 4 - Université de Blida 1, Faculté de Technologie (Algeria)

Abstract

In this work, the Japanese standard for seismic evaluation of existing reinforced concrete buildings (2001) have been adapted and applied to the constructions in the northern region of Morocco. In the past, the region had suffered from numerous earthquakes, lately the 2004 earthquake near the city of Al Hoceima (Mw of 6.4 causing more than 600 fatalities) and is constantly subject to seismic threat. The Japanese standard was selected because it provides accurate results in case the constructions are low-rise RC buildings, which is the case for the majority of the buildings in north of Morocco. Nevertheless, multiple modifications have been made to adapt the standard to the construction features of Moroccan RC buildings and have been applied to 4180 existing building in the cities of Al Hoceima and Imzouren. The results show that a significant percentage of the buildings have a high seismic vulnerability. The maps elaborated can be a potential guide to the decision making in the field of seismic risk prevention and mitigation strategy; these maps also constitute valuable information for urban planning and the development of the northern cities.

Keywords: RC buildings, Seismic Index Method, Al Hoceima, Imzouren

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*Corresponding author Fathi Badr-Eddine <[email protected]>


S.06: EVALUATION OF THE FUNCTIONS OF THE WETLAND COMPLEX BAS LOUKKOS BY GIS AND REMOTE SENSING

Fathi Badr-Eddine 1, Afilal Tribak Abdelghani 1, Wahbi Meriam 1

1 - Faculty of Science and Technology in Tangier (Morocco)

Abstract

The estuary of Loukkos river is a complex ecosystem classified in the list of the international convention Ramsar, different factors are acting on this wetland. Our study aims to shed light on the contribution of remote sensing to the evaluation of the functions of the wetland by remote sensing: hydrological biogeochemical and ecological, as well as the concepts, tools and methods used. on the other hand, the delimitation and characterization of wetland and the spatiotemporal monitoring of the land use of complex bas Lukkos Ramsar site located at the mouth of Loukkos river on the outskirts of Larache with the aid of the remote sensing tool during the last three decades. The Evaluation of the functional status of wetlands in relation to land use and development is based on the coupling different types of remote sensing data (aerial photographs, airborne and satellite multispectral images, passive and RADAR images), which increases the possibilities of identification and characterization of wetlands. Validation of the observation data and models obtained after treatment is done by measuring certain parameters on the ground (variation of the level of the water surface, digitization and delineation of the marshes) during a year due to a sampling by me in the sampling sites. The results obtained will allow to make a diagnosis of the current state of the functions of the bas Loukkos complex wetland. The GIS infographic study and the remote sensing allows us to make a rather fine characterization of this complex and monitor land use during the last thirty years and to evaluate its functioning in order to ensure the values and functions of this wetland classified in the Ramsar Convention, 1972. And allow its sustainable development.

Keywords: Wetland, Remote sensing, Modeling, Land use, GIS.

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*Corresponding author Tahouri Jad <[email protected]>


S.06: STUDY OF THE IMPACT OF THE SPATIAL AND TEMPORAL DISTRIBUTION OF URBAN HEAT ISLANDS USING REMOTE SENSING AND GIS TECHNIQUE IN THE REGION OF NADOR (ORIENTAL RIF, MOROCCO)

Tahouri Jad 1, Sadiki Abdelhamid 1

1 - Laboratory of Geodynamics and Natural Resources (LGRN), Faculty of Sciences Dhar El Mahraz, University Sidi Mohamed Ben Abdellah, Fez-Morocco. (Morocco)

Abstract

A global alarm is triggered to deal with the impact of artificialisation of soils and natural environments. The formation of an urban heat island (UHI) is one of the most disastrous impacts of the urbanization process. To cope with this phenomenon, good planning of green spaces in urban areas and the protection of natural areas remains the effective tool used in such cases. The objective of this study is to evaluate the spatial and temporal distribution of UHI in Nador region based on the single channel method (SC) and the split-window algorithm (SW). For this, the study followed these methodological steps: 1) Mapping of the land use / land cover change (LULC) for the years 2007 and 2017 using supervised classification and the maximum likelihood method; 2) Application of the single-channel (SC) and split-window (SW) methods to obtain spatial and temporal models of the Earth's surface temperature (LST); 3) The correlation between LSTs and Normalized Difference Vegetation Index (NDVI) and Standardized Difference Accumulation Index (NDBI), but also a new index called Enhanced Built-Up and Bareness Index (EBBI); 4) The application of the ecological assessment index. The results showed an increase in average LST values of around 8 ° C in urban areas and 5 ° C in undeveloped areas. In addition, the positive close correlation between LST, NDBI and EBBI showed an amplification effect of the developed areas for the UHI, while the predominantly vegetated areas attenuated the effect of the UHI. Urban centers, grouped in some parts, received the worst ecological assessment index. Finally, the adoption of these new decision support tools has shown their reliability in other countries for good land and use planning, to mitigate the effect UHI and ensure thermal comfort in built-up areas and the management of natural resources in an efficient and sustainable manner.

Keywords: Land Surface Temperature (LST), Urban Heat Island (UHI), Soils

artificialisation, NDVI, NDBI, Enhanced Built, Up and Bareness Index (EBBI), Nador, Morocco.

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*Corresponding author Al-Mahfadi Afrah <[email protected]>


S.06: CLIMATE CHANGE EFFECT IN AHWAR ESTUARY AREA IN YEMEN DURING (1985 - 2015)

Al-Mahfadi Afrah 1, Dakki Mohamed 1

1 - Research Unit for Wetlands Management, Scientific Institute, Mohamed V. University, Rabat, Morocco (Morocco)

Abstract

Coastal areas are rich of ecosystems and habitats which have goods and services for people such as fisheries, agriculture and salting. The coastal area are the most sensitive region to climate change and its various consequences. Yemen has been identified as hosting globally important biodiversity. This biodiversity is particularly rich in coastal area which is over 2500 km long and overlapping three different seas with different characteristics: Red Sea, Gulf of Aden and Arabian Sea. Ahwar coast, which faced the Gulf of Aden, is located in the eastern part of Abyan Governorate. The case study is one of these have experienced coastal flooding and with storm surges such as the floods in 1991 and 1993 as well as the storm in 2015. The objective of this research helped to identify the different climate change aspects which effect Ahwar coast area. The methods of this research are geospatial tools such as GIS and Google earth image from 1985 until 2015 that was based existing data and literature. Moreover, this paper analyzed coastal vulnerability to climate change, and which possible adaptation options. The result shows climate change poses a major threat and should be taken into account by makers-deciosn. The temperature will be increased (about 1.4°C and 2.8°C) and rainfall will be reduced about 24% by the year 2050. Thus, part of Ahwar coastal area could be submerged. The estuary of Ahwar has increased erosion and sedimentation during 1985 - 2015. Finally the recommendations are given to improve some practical adaptation measures by; improving building capacity to adapt and monitoring climate change affects; improving water management and developing the integrated coastal zone planning; raising awareness among all stakeholders; and implementing emergency project to implement some activities against climate change.

Keywords: Coastal region, Climate change, GIS, Ahwar estuary, Yemen

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*Corresponding author Hakdaoui Sofia <[email protected]>


S.06: COASTAL VULNERABILITY MAPPING USING THE ANALYTICAL HIERARCHICAL PROCESS CASE OF AD-DAKHLA IN SOUTHWESTERN MOROCCO

Hakdaoui Sofia 1, Emran Anas 1

1 - Earth Observation Lab (Morocco)

Abstract

It is paradoxical that the countries least responsible for global climate change are in fact the most vulnerable to its adverse effects. The Moroccan coast and more particularly, the Saharan coast is characterized by long stretches of beaches with fine sand in the middle of sections in cliffs, the immense bay of Dakhla (37 km long and 12 km wide) and its peninsula constitute a true pool of unlimited beaches which is facing a potentially multi-hazard threat due to climate change. In this paper an analytical hierarchical process (AHP)-based approach to coastal vulnerability studies. The process combine socio-economic parameters with the physical parameters to calculate the coastal vulnerability index using AHP-derived weights. Eight physical?geomorphological parameters (coastal slope, geomorphology, lithological nature of sediments elevation, shoreline change rate, rate of sea level change, significant wave height and mean tide range) and four socio-economic factors (population, land use/land cover (LU/LC), roads and location of tourist areas) are considered to measure the physical vulnerability index (PVI) as well as the socio-economic vulnerability index (SVI) of the dakhla coast. These variables are integrated through recent geospatial techniques (Sentinel-1 radar coregistration and interferometry) and compared to those obtained from old geospatial data (Shuttle Radar Topographic Mission (SRTM), and then ranked to estimate the degree of coastline vulnerability to sea level rise. The results show that sentinel-1 radar data gives more accurate mapping of coastal vulnerability compared to those obtained by SRTM data.

Keywords: Coastal vulnerability, Remote Sensing, Radar SAR

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*Corresponding author Ouallali Abdessalam <[email protected]>


S.06: MODELING AND SPATIALIZATION OF WATER EROSION ON THE LANDS OF TWO BASINS OF THE WESTERN MOROCCAN RIF.

Ouallali Abdessalam 1, Moukchane Mohamed 1, Aassoumi Habiba 1

1 - Université Abdelmalek Essaadi. Faculté des sciences de Tétouan (Morocco)

Abstract

This study reflect the adaptation of one of the models of spatialization of soil erosion in two watersheds of Moroccan Western Rif. The first named Arbaa Ayacha with a double Mediterranean and Atlantic influence and the second (Rmel watershed) with a purely Mediterranean influence. These two sites constitute a favorable environment for the development of water erosion phenomena resulting from their topographic, lithological and climatic characteristics. The aim of this study is to evaluate and compare the erosive states and the different causal factors of erosion risk in the two watersheds by adapting the cross-matrixes of the PAP / RAC guidelines (1997) on the one hand. On the other hand, to increase the contribution of spatialization techniques in the study and monitoring of erosion risks. This method is based on three approaches. The predictive approach provides a synthetic map of the distribution of erosive states, with most of the two basins at high risk. Descriptive mapping of the different forms of erosion shows a considerable extension of strip and erosion, surface gullies and moderately deep gullies for the collection of flows from upstream to downstream. The superposition of the results of the predictive and descriptive approaches gives a consolidated PAP / RAC map whose analysis shows that soil loss throughout the basin is proportional to the increase of the main water erosion factors according to the level of importance.

Keywords: Rmel, Arbaa Ayacha, PAP/CAR, Runoff, Soil erosion, Rif, Morocco

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*Corresponding author Bahrouni Nejib <[email protected]>

Poster: GIS and Risk Scenario https://afsc2018.sciencesconf.org/194728/

S.06: NEOTECTONIC AND SEISMOTECTONIC INVESTIGATION IN SEISMICALLY ACTIVE REGIONS OF TUNISIA: SEISMOGENIC POTENTIALITIES AND SEISMIC HAZARD ASSESSMENT

Bahrouni Nejib 1, Merzougui Wissem 1, Maamri Ridha 1, Dhaha Faouzi 1, Bouaziz Samir 2

1 - Geological survey, National Office of Mines (Tunisia), 2 - University of Sfax, National Engineering School of Sfax (Tunisia)

Abstract

Most of Tunisian land is seismically active with significant historical and active deformations, showing recent seismic events and their relative surface effects. Seismically active regions have significant historical and recent deformations, showing seismic events. It is prone to a continuous seismotectonic activities represented by a relatively low seismicity. Recent investigations on active deformation in active zones aim to develop new databases for detailed studies of recent tectonics, geological information collected in Quaternary deposits. Seismo-tectonics, historical seismicity, ruptures, and surface effects in selected as risky to represent several types of deformations. Spatial distribution of recent earthquakes epicenters indicates that the main activities took place in Northwestern Atlas, Southern Atlas, Eastern and Pelagic platform and Tunis surroundings. Field investigations of active zones included identification of active fault characteristics, and their relation with major structural features; analysis of brittle tectonic deformation affecting Quaternary deposits, and determination of focal mechanism of most Tunisia earthquakes within the frame of its broader structural context. These field data led to establish an earthquake distribution map as well as major seismic zones that provided better understanding of the seismic zoning, reconstruction of the Quaternary stress tensor, assessment of the seismic hazard and seismic risk to infer new conclusions on the seismogenic zones. Reconstructed regional stress tensor updates neotectonic deformation models and the seismotectonics of Tunisia that can be integrated within the largest frame of the orogenic dynamics of the North African margin. Main seismic activities of Tunisia, as a key area of the Northern African plate, were mainly caused by inter-plate deformations along major active faults.

Keywords: Neotectonics, Seismotectonic, Active fault, seismogenic zone, seismic

assessment, African margin, Tunisia.

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*Corresponding author Ousmana Habiba <[email protected]>


S.06: GIS AND GUIDELINES PAP / RAC FOR MAPPING AND MODELLING OF WATER EROSION RISK PROCESSES IN THE WATERSHED OF OUED ZGANE, (MIDDLE ATLAS MOROCCO)

Ousmana Habiba 1, El Hmaidi Abdellah 1, El Abassi Mourad 1, Essahlaoui Ali 1, Bekri Hachem 1, El Ouali Abdelhadi 1

1 - Department of Geology, Faculty of Sciences, University of Moulay Ismail (Morocco)

Abstract

Water erosion is one of the biggest environmental problems in Mediterranean regions with semi-arid climates. Several methodologies for water erosion assessment have been developed; many of these are supported by Geographic Information Systems and remote sensing. The aim of this study is to map vulnerability to water erosion based on the Priority Actions Programme/Regional Activity Centre (PAP/RAC) method combined with Geographic Information Systems (GIS) of the Oued Zgane Watershed. This watershed, sheltering Ifrah, Iffer and Afourgagh lakes, is located in the north of the Middle Atlas, Morocco, in the tabular Middle Atlas causse.The predictive approach, the first step of the PAP / RAC method, provides a synthetic map of the distribution of erosive states, with 19.48% of the total area of the catchment area subject to a high and very high degree of erosion. The descriptive cartography of the various forms of erosion, the second step of PAP / RAC, shows that 84.7% of the basin area is known by the rigids, the superficial gullies and the sheet erosion. The superposition of the results of the predictive and descriptive approaches, 3rd phase of PAP / RAC, carried out the consolidated PAP / RAC map showing soil losses in the study area proportional to the increase of the main factors of water erosion. This consolidated erosion map indicates maximum soil losses in relation to moderately deep ravines located to the northeast of the watershed.The presence of these forms may be related to the steep slope, the aggressiveness of the rains and the lack of vegetation cover.

Keywords: Water erosion, PAP/RAC method, Geographic Information System (GIS),

Watershed, Oued Zgane, Tabular Middle Atlas.

77

*Corresponding author Naiji Zakariae <[email protected]>


S.06: MODÉLISATION ET SIMULATION 2D DU RISQUE D'INONDATION DANS LA VILLE DE ZAÏO (MAROC NORD-ORIENTAL)

Naiji Zakariae 1, Lazzar Ayoub 1, Oujidi Mostafa 1, Rezqi Halima 1

1 - Université Mohammed 1er, Faculté des sciences Oujda, Département des sciences de la terre, Laboratoires des Géosciences appliquées (Morocco)

Abstract

La ville de Zaïo objet de la présente communication fait partie de la région de l'Oriental située au Nord ?Est du Maroc. Elle a été fondée au pied de la chaine des Kebdana sur un cône de déjection occasionnellement fonctionnel, elle s'étale vers le sud sur la frange nord du périmètre irrigué de la plaine de Sebra. Ce contraste topographique est responsable des fréquentes et de graves inondations que connaît la ville de Zaïo telles celles enregistré en 2003 et en 2007. L'étude du risque d'inondation intègre aussi bien la composante naturelle (Aléa) et la composante sociale (vulnérabilité). Ainsi, le Risque = Aléa x Vulnérabilité. Le but de la présente communication est de réaliser une carte du risque aux inondations de la ville de Zaio. La méthodologie adoptée se base sur une étude hydrologique afin de calculer le débit maximum de la région et une étude hydraulique pour déterminer la vitesse et la hauteur des crues centennales des différents Oueds à l'aide du logiciel Iber 2.0.3. Les résultats seront présentés sous forme des cartes thématiques à l'aide du logiciel Arcgis 10.4. Ces cartes seront des outils d'aide à la décision pour les aménagistes et les autorités locales en vue d'agir plus efficacement en cas de crue et de proposer des mesures d'atténuation dans les zones à fort risque d'inondations. Ainsi, l'étude a montré la prédominance de l'aléa inondation élevé alors que la vulnérabilité est plus modérée ; en effet, elle est de plus en plus ressentie avec l'expansion que connaît la région en matière d'urbanisme et d'infrastructures.

Keywords: bassins versant, hydraulique, cartographie, Zaio, Le risque d'inondation,

vulnérabilité, aléa, ArcGis, Iber 2.4.3

78

*Corresponding author Chaieb Ali <[email protected]>


S.06: CARTOGRAPHY OF SEISMIC HAZARD IN THE PLAIN OF KASSERINE (WESTERN TUNISIA) USING MORPHOMETRIC INDEXES-SEMI AUTOMATED APPROACH

Chaieb Ali 1, Rebai Noamen 2, Bouaziz Samir 3 4 5

1 - STUDENT (Tunisia), 2 - PROFESSOR (Tunisia), 3 - PROFESSOR (Tunisia), 4 - University of Sfax, National Engineering School of Sfax, LR. ?Water-Energy-Environment? (Tunisia), 5 - Ecole Nationale d'ingénieurs de Sfax, Département de Génie Géologique (Tunisia)

Abstract

The application of morphometric parameters on the Digital Terrain Model and hydrographic network allows us developing the thematic maps of areas which are tectonically active. In this study this integrative methodology was used to evidence the active tectonics in the Plain of Kasserine in western part of Tunisia. Morphostructural analysis is improved by developing a morphometric GIS based primarily on the use of topographic and geological mapping data. Processing performed concerns on one hand contours and drainage patterns of the topographic map at 1/50000 and the tectonic geological map. Results of processing are layers of information in vector format: "SHP" incorporated into a GIS using ArcGIS 9.3 software. They are presented in the same map with the coordinate system (UTM zone 32, WGS84). These vector layers are: 1 - tectonic accidents, 2 - the water system, 3 - the drainage anomalies. This also allowed us to project the position of seismic focal in the same map. Mapping results of morphometric indexes are validated by field observations at different sites located near a recent seismic earthquake. Results clearly prove the existence of relationship between morphometric parameters alignment and seismic focal corresponding to that recent earthquake. These results also emphasize the existence of an active accident in the quaternary deposits (western Tunisia); this active accident is thought to be responsible of the corresponding earthquake. Morphometric parameters are good indicators of active tectonics. Actually, throughout drainage anomalies mapping, the location in the same map of the seismic focal, and tectonic accidents as well as field observations at different sites near the seismic focal, we pinpoint at first the existence of an active tectonic fault.

Keywords: Seismic risk, Cartography, Morphometriy, quaternary plain

79

*Corresponding author Bourhili Amine <[email protected]>


S.06: LA CINEMATIQUE D'EVOLUTION DU TRAIT DE COTE DU LITTORAL D'EL JADIDA FACE A LA VULNERABILITE

Bourhili Amine 1, Bendahhou Zourarah 1, El Khalidi Khalid 1, Elkailech Youssef 1

1 - Laboratoire Géosciences Marines et Sciences du Sol (URAC-45) (Morocco)

Abstract

La zone côtière est l'un des plus grands atouts environnementaux et économiques de la nation. La présente recherche se concentre, d'une part, sur l'analyse du taux de changement du trait de côte par des techniques analytiques automatiques en utilisant une photo-interprétation acquise en 1970, 1982 et 2010 qui est analysée sous le système d'information géographique (SIG) à l'aide de l'extension DSAS (Digital Shoreline Analysis System) le long de la côte d'El Jadida. Et d'autre part, elle se concentre sur l'évaluation de la vulnérabilité côtière en se basant sur des indices quantitatifs, ce qui est considéré comme une étape clé pour la prévention et la gestion et l'atténuation des catastrophes. A partir des photos aériennes multi-dates du littoral d'El Jadida, le taux de changement a été calculé en utilisant l'indice End Point Rate (EPR). L'analyse des résultats obtenus montre que la côte a une tendance en général évolutive régressive le long des 18 km de côte étudiés. En effet, sur les 910 transects analysés, 744 (70.77 %) sont en érosion et 266 (29.23 %) sont en accrétion. La vulnérabilité a été évaluée à partir de l'indice de vulnérabilité côtière (IVC) qui est estimé en fonction de sept sous-indices. Chaque indice a été classé en cinq catégories de vulnérabilité : très faible, faible, moyenne, forte et très forte. L'analyse des résultats obtenus montre que la vulnérabilité est très forte au niveau de la baie d'El Jadida, moyenne au niveau du platier rocheux de la plage Deauville et très faible le long de la plage d'El Houzia jusqu'à l'embouchure d'Oum Rbiâ.

Keywords: Digital Shoreline Analysis System (DSAS), changement du trait de côte,

Accrétion, Erosion, Littoral d'El Jadida, Vulnérabilité côtière.

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*Corresponding author El Gabry Mohamed <[email protected]>

Oral: Earthquake Hazard Assessment https://afsc2018.sciencesconf.org/197917/

S.07: SEISMIC ASSESSMENT OF A CULTURAL HERITAGE STRUCTURE IN CAIRO CONSIDERING THE SCENARIO BASED APPROACH

Hassan Hany 1 2, Sayed Mohamed 2, Romanelli Fabio 1, Amadio Claudio 3, El Gabry Mohamed 2

1 - Department of Mathematics and Geosciences, (Italy), 2 - National Research Institute of Astronomy and Geophysics [Helwan] (Egypt), 3 - Department of Engineering and Architecture (Italy)

Abstract

Finding a proper mitigation strategy for cultural heritage structures should highly based on the hazard assessment at the site of interest, and utterly on our understanding of the performance of such structures during the earthquake shaking. It is well known that each building has its own characters; therefore, different requirements are needed for the building under study according to the available information about its present condition e.g. the building type, site-condition, expected ground motion level and surroundings. In this work, we assessed the seismic vulnerability of a well-preserved cultural heritage structure that is the minaret of the Madrasa of the Princess Tatar al-Higaziya in the old Cairo, named the minaret. At the minaret, we provide the Maximum Credible Seismic Input (MCSI), to be used for the assessment of the dynamic behavior of the minaret, obtained by joining both scientific and engineering knowledge in order to interpret the performance of this monument under earthquake shaking. Detailed numerical model of the minaret is established in SAP2000, while linear elastic analysis is conducted under the earthquake loading. The C-MCSI at 50th percentile spectrum is applied in bi-direction (X- and Y-direction) to minaret considering the soil subgrade reaction coefficient. The results show that the minaret suffered significant principle tensile stresses that exceeded the allowable exceed the tensile strength of the building stone (limestone) in the minaret. The results of the principle tensile stresses denote enormous cracking and even crushing in the minaret, particularly at the base and at the geometry transition zone right above the base. Furthermore, the level of the tensile stresses predicts collapse or severe damage of the minaret under the C-MCSI-50% bidirectional response spectrum. The results could be a prototype for s risk reduction of heritage structures, especially those with same age and similar structural system and components.

Keywords: Seismic assessment, Cultural heritage structure, Cairo

81

*Corresponding author Benouar Djilali <[email protected]>


S.07: RESEARCHING ENGINEERING CAUSES IN 2003 BOUMERDES-ALGIERS (ALGERIA) EARTHQUAKE DISASTER: A FORENSIC STYLE METHODOLOGY

Benouar Djilali 1

1 - Université des Sciences et de la Technologie Houari Boumediene [Alger] (Algeria)

Abstract

Disasters are increasingly being understood as ?processes' and not discreet ?events'. Moreover, the causes of disasters are driven by complex engineering, socio-economic, socio-cultural, and various geophysical factors. Such interacting driving factors, occurring across a range of temporal and spatial scales, combine in numerous ways to configure disaster risks. Using some selected disasters in Algeria, the dynamics of such risks and their configurations will be explored using a new approach and methodology, namely Forensic Disaster Investigations (FORIN methodology). The FORIN methodology came out of the recognition despite of the considerable increase in knowledge about disasters; unfortunately losses are not showing any corresponding decrease. Indeed, it seems, the more we have learned, the more we are losing. The FORIN methodology is based on the idea that this situation is due to the fact that much current research is still informed by a focus on surface symptoms of observations and events rather than critical causes and processes of disaster risk construction and accumulation. Forensic task is perhaps similar to solving a picture of a disaster puzzle. Initially, there are dozens or even hundreds of apparently disorganized pieces piled when examined individually, each piece may not provide much information. When a significant portion of the disaster puzzle has been solved, it then becomes easier to see where the remaining pieces fit. The Integrated Research on Disaster Risk programme is proposing new methodologies to examine the root issues surrounding the increase in disaster cost both human and economic. This paper attempts, as a case study, to investigate the Algiers (Algeria) earthquake disaster of 21 May 2003 which caused the loss of more than 2,278 human lives, injuring more than 11,450, making 1,240 missing and 182,000 homeless; it destroyed or seriously damaged at least 200,000 housing units and about 6,000 public buildings in five provinces.

Keywords: Forensic, Risk Reduction, Forin methodology, Case study, Earthquake hazards.

82

*Corresponding author Rfifi Mohamed <[email protected]>


S.07: APPLICATION OF CRISIS CODE TO ASSESS THE SEISMIC HAZARD IN THE EASTERN RIF OF MOROCCO

El Mahsani Abderahman 1, Ait Brahim Lahsen 2, Rfifi Mohamed 1, Tadili Ben Aissa 3 4, Lallout Imane 1, Dahaoui Mohamed 5, Tlemcani Mohammed 6

1 - Université Mohammed V, Faculté des sciences de Rabat, Unité de recherche GEORISK, LGRN (Morocco), 2 - Faculté des sciences [Rabat] (Morocco), 3 - Iservice Pro (Morocco), 4 - Université Mohammed V, Institut scientifique de Rabat (Morocco), 5 - Université Mohammed V, Faculté des sciences de Rabat, Unité de recherche GEORISK, LGRN (Morocco), 6 - Université Mohammed V, Institut scientifique de Rabat (Morocco)

Abstract

Even though it has never been validated by objective testing, Probabilistic Seismic Hazard Analysis (PSHA) has been widely used for almost 50 years by governments and scientific community in applications with lives and property. A probabilistic seismic hazard analysis technique was used to estimate strong ground motion parameters for the eastern Rif in northern Morocco (where remarkable earthquakes occurred during the last two decade). The five source zones were established on the basis of the seismicity database collected and updated. By the use of this information and the application of the Gutenberg?Richter law (GR law), the seismic parameters for each source zones have been extracted. The computer program CRISIS has been used for displaying maximum ground acceleration map (PGA) for 50 year return periods. This results expressed indicate the zones presenting an elevated hazard and their comparison to the main active faults in the area.

Keywords: Seismic Hazard, seismicity database, maximum ground acceleration, CRISIS

program, the Gutenberg, Richter law, source zones, eastern Rif, Morocco

83

*Corresponding author Tahouri Ouassim <[email protected]>


S.07: USING GIS TECHNIQUES FOR THE STUDY OF THE EVOLUTION OF EARTHQUAKES IN MOROCCO BETWEEN THE PERIOD FROM 1901 TO 2010

Tahouri Ouassim 1 2, Dridri Abdallah 3, Tahouri Jad 1 2

1 - Laboratory of Geodynamics and Natural Resources (LGRN), Department of Geology, Faculty of Sciences Dhar El Mahraz, University Sidi Mohamed Ben Abdellah, Fez, Morocco (Morocco), 2 - Moroccain Association of Protection of Heritage and Barbary Macaques (PPSM) (Morocco), 3 - Laboratory of Geosystem - Environment and Sustainable Development, Department of Earth Sciences, Faculty of Sciences Dhar El Mahraz, University Sidi Mohamed Ben Abdellah, Fez, Morocco (Morocco)

Abstract

Earthquakes are one of the natural disasters that humans fear most, they can devastate entire regions in seconds causing disastrous effects. An earthquake can cause other natural phenomena such as floods, avalanches, tsunamis, landslides, liquefaction of the soil. The purpose of this study is to show which areas of Morocco have the highest risk of earthquakes using geographic information systems (GIS) and to identify areas where appropriate precautions must be taken. For this, the realization of the map of seismicity of Morocco and its surroundings is based on the use of a database global of the various points of earthquake of the period going from 1901 to 2010. For this, it proves necessary to use GIS techniques. The present work have a objective to create an earthquake maps point's repair in Morocco. The results show that most epicentres of current and historical earthquakes are located largely in northern Morocco. They were aligned along a subequatorial line bounding the African plate and the Eurasian plate. The observed limit runs along the Mediterranean Sea from the Arabian microplate, passes through the Strait of Gibraltar, the Azores and connects with the Mid-Atlantic ridge. This remarkably seismogenic limit is characterized by its particular kinematics. It was admitted that the activity of the boundary is striking between the Atlantic ridge and the Alboran Sea; In the central and eastern Mediterranean, the activity of the boundary is overlapping with the subduction of the African crust under the Eurasian plate. Despite this geodynamic complexity, we are witnessing a progress of the African plate towards the Eurasian plate in a globally NS trajectory, at an increasing speed from west to east of the order of 3 to 4mm / year at the arc level. Gibraltar, 10mm / year in the eastern Mediterranean.

Keywords: Earthquakes evolution, GIS techniques, Earthquake map, Morocco.

84

*Corresponding author Ksentini Ahmed <[email protected]>


S.07: TOWARD PROBABILISTIC SEISMIC HAZARD MODEL SELECTION FOR AFRICA

Ksentini Ahmed 1 2, Romdhane Najla 2

1 - assistant professor (Tunisia), 2 - National Engineering School of Tunis (Tunisia)

Abstract

Recent seismic hazard models are based on probabilistic models (US-NSHMP, European-SHARE...). In such evaluation, modelers can define different seismic source models ; area sources, actives faults, gridded seismicity, geodetic models. In addition, the inherent uncertainties from gound motion prediction, maximum magnitudes, source models are trated using logic tree approach. in this work, a detailed comparison between seismic source models and logic tree branches is presented to help understanding the best hazard assement for africa depending on the available data for the continent. Active fault slip rates, GPS velocities and catalogue seismicity rates correlation in global context are presented in different approaches to guide the model choice and calibration. It aims also to understand which seismic source models are enough mature for the continent to best describe actual seismicity and maximum expected magnitudes. A first preminary attempt to model the hazard for africa is presented to analyze the available tools and engines and their capabilities to evaluate both the hazard and the seismic risk.

Keywords: seismic sources, eathquake hazard, logic tree, seismic risk, open tools, seismicity

rates

85

*Corresponding author Delvaux Damien <[email protected]>


S.07: NEOTECTONICS AND SEISMOTECTONICS OF THE KIVU RIFT BASIN: IMPLICATIONS FOR SEISMIC HAZARD ASSESSMENT

Delvaux Damien 1, Fiama Sylvanos B. 2, Ganza Gloire B. 3, Havenith Hans-Baalder 4

1 - Royal Museum for Central Africa, Tervuren, Belgium (Belgium), 2 - Centre de Recherche en Sciences Naturelles (Congo - Kinshasa), 3 - Université Officielle de Bukavu (Congo - Kinshasa), 4 - University of Liège (Belgium)

Abstract

The Kivu rift basin is one of the most geodynamically active segments of the western branch of the East African Rift System, combining different kind of geological hazards (earthquakes, volcanism and mass movement) in a highly populated and weakly developed area. This basin makes the junction between the Tanganyika rift segment to the South and the Albertine rift segment to the North. In order to assess the seismic hazard of this region, we constructed homogeneous geological, structural and neotectonic maps cross the five countries of this region, mapped the pre-rift, early rift and Late Quaternary faults and compiled the existing knowledge on thermal springs (assumed to be diagnostic of current tectonic activity along faults). We also produced also a new catalog of historical and instrumental seismicity and defined the seismotectonic characteristics (stress field, depth of faulting) using published focal mechanism data. We evidenced that the rift structure developed in two successive stages, controlled by the existing structure of the basement. The current stress field stress field revealed by earthquake focal mechanisms appears strongly influenced by this heterogeneous structure but also by the transition towards the Congo basin on the western side of the rift and towards the Tanzanian carton on its eastern side. Seismic hazard assessment using the new earthquake catalog, maximum likelihood method and Crisis 2012 software reveal that the currently non-magmatic southern part of the Kivu rift as the northern part of the Tanganyika rift has the highest seismic hazard.

Keywords: Central Africa, seismic hazard, seismotectonics, neotectonics, Kivu rift

86

*Corresponding author Ateba Bekoa <[email protected]>


S.07: POST-ERUPTIVE SEISMIC ACTIVITY OF MOUNT CAMEROON FOR THE PERIOD 2005-2016

Ateba Bekoa 1, Mbossi Eddy Ferdinand 2

1 - Institut de Recherches Géologiques et Minières (Cameroon), 2 - Institut de Recherches Géologiques et Minières (Cameroon)

Abstract

Located in the Gulf of Guinea, Mount Cameroon is part of an alignment on nearly 1600 km of volcanic islands and continental volcanoes. Its volcanic eruptions are usually preceded by seismic crises, which are thus perceived as a major precursor. Since its last eruption in 2000, we continued monitoring its seismicity. It is diffuse on the flanks and distributed in the crust and below to depths of more than 60 km. In the crust, there is a correlation between seismicity and tectonics, and the recorded signals are of the tectonic origin. On the other hand, events of deeper origin are volcano-tectonic type are generally located on the east flank. Seismicity is characterized by a monthly average frequency of 20 to 30 events, all of magnitude <3. During periods of crisis, this frequency is at least doubled. Between 2005 and 2016, at least three periods of seismic swarms lasting at least two months were observed in 2010, 2012 and 2014. For example, frequencies of greater than 200 earthquakes per month were recorded for more than two months in 2014, without resulting in a volcanic eruption. The period following the last 2000 eruptions would be characterized by low stress concentrations, which would explain the absence of felt earthquakes or the initiation of a new volcanic eruption. Thus, all seismic swarms on Mount Cameroon do not necessarily announce a volcanic eruption.

Keywords: volcanic eruption, seismicity, Mount Cameroon, tectonics

87

*Corresponding author Mohamed Hamdache <[email protected]>


S.07: A FORECASTING MODEL FOR M>5 EARTHQUAKES USING SPATIALLY-SMOOTHED SEISMICITY. APPLICATION FOR THE ALGERIA-MOROCCO REGION.

Mohamed Hamdache 1, Jose Pelaez 2, Karim Yelles-Chaouche 3

1 - Centre de Recherche en Astronomie, Astrophysique et Géophysique (Algeria), 2 - Department of Physics University of Jaen Spain (Spain), 3 - Centre de Recherche en Astronomie, Astrophysique et Geophysique (Algeria)

Abstract

The studied region has suffered moderate to strong earthquakes in the last decades. Among them, the September 9, 1954, and the October 10, 1980, El Asnam, Algeria, earthquakes, with magnitudes MS 6.7 and 7.3, respectively, the February 29, 1960, Agadir, Morocco, M ~ 6.0 earthquake, or the most recent May 21, 2003, Zemmouri-Algiers, Algeria, MW 6.8 earthquake. The 1954, 1980 and 2003 Algerian earthquakes caused a large loss of lives (1200, 5000 to 20000, according to different estimates, and 2300 dead, respectively), as well as the 1960 Moroccan earthquake (~12000 dead). Forecasting earthquakes, in this or other regions, is a crucial task, mainly for two reasons. One of them merely scientific: forecasting is one of the main goals of the scientific knowledge. The second one practical in itself: We study the correlation between locations of M>5 earthquakes and locations of 5>M>4.0 events for Northern Algeria and Morocco. It can be observed a relatively good agreement between locations for these two data sets, that is, minor earthquake locations could be used to forecast future places where will happen moderate to strong earthquakes. Then, a time-independent forecasting model based on the spatially smoothed seismicity rate of M>4.0 earthquakes is proposed. Initially, the area under study was divided into square cells. The number of earthquakes with magnitude M>4.0 that have taken place at a given cell is counted and spatially smoothed. The time-independent forecasting model is proposed from the computation of M>5.0 earthquake probabilities for each cell for different exposure times. Probabilities are computed assuming a Poisson process and the Gutenberg-Richter magnitude-frequency relationship. Among the obtained results, we highlight the delineation of potential areas, from a probabilistic point of view, to host future earthquakes with magnitudes and in the studied region.

Keywords: Forecasting, spatially smoothed seismicity, Algeria, Morocco.

88

*Corresponding author Mavonga Tuluka Georges <[email protected]>


S.07: SEISMIC HAZARD ASSESSMENT OF THE DEMOCRATIC REPUBLIC OF CONGO AND SURROUNDING AREAS BASED ON RECENT COMPILED SEISMIC ZONATION SOURCE MODELS

Mavonga Tuluka Georges 1, Delvaux Damien 2, Durrheim Raymond 3, Lukindula Jeanpy 1

1 - Goma Volcanic Observatory (Congo - Kinshasa), 2 - Royal Museum of Central Africa, l (Belgium), 3 - School of Geosciences, Univ. of the Witwatersrand (South Africa)

Abstract

A new probabilistic seismic hazard assessment has been performed for the Democratic Republic of Congo (DRC) and surrounding areas. The DRC encompasses both intra-plate and active tectonic areas associated with the Congo Craton and the western branch of the East African rift system, respectively. The seismic hazard assessment is based on a new Sub-Saharan-Global Earthquake Model (SSA-GEM) earthquake catalogue with homogeneous magnitude representation (Mw).The initial declustered catalogue has 782 events. Tthe final catalogue declustered used for the seismic hazard assessment spans 55 years, from 1960 to 2015 with 398 events and a magnitude of completeness of about 4.5. The seismotectonic zonation was done on the basis of the regional geological structure, neotectonic fault systems, basin architecture and distribution of thermal springs and earthquake epicenters. Also, consideration was given to a regional strain rate model developed for the East Africa Rift by Stamps et al. in the frame of the GEM Strain Rate Project. The current area source model consists of a total of 15 seismic zones distributed over 6 main tectonic groups which we assume to have comparable rheological and mechanical behavior with respect to the underlying crustal geology. The Gutenberg-Richter seismic hazard parameters were determined by the least square linear me-thod.Hazard computations have been performed using the latest OpenQuake-engine (Version 2.7.0). Spectral acceleration has been computed at PGA and for the response spectral periods of 0.05 s, 0.1 s, 0.2 s, 0.5 s, 1 s and 2 s using four GMPE: two for active shallow crust and two for stable continental conditions for site soils corresponding to Vs30 =600, 760 and 1500 m/s . Result obtained in term of PGA is consistent with that obtained by Damien et al., using average value of PGA computed from three regional GMPE in 4 cities in Kivu Rift segment using Crisis 2012 software.

Keywords: probabilistic seismic hazard assessment, seismic zonation source model,

earthquake catalogue, openquake engine.

89

*Corresponding author Kariche Jugurtha <[email protected]>,


S.07: THE AL HOCEIMA EARTHQUAKE SEQUENCE OF 1994, 2004 AND 2016: STRESS TRANSFER AND POROELASTICITY IN THE RIF AND ALBORAN SEA REGION

Kariche Jugurtha 1 2, Meghraoui Mustapha 3, Timoulali Youssef 4, Cetin Esra 5, Toussaint Renaud 6

1 - Institut de Physique du Globe, CNRS-UMR7516, EOST - Universite de Strasbourg (France), 2 - USTHB, Laboratoire de Geophysique, FSTGAT, B.P. 32 El Alia, 16111 Bab Ezzouar, Algiers, Algeria (Algeria), 3 - Institut de Physique du Globe, CNRS-UMR7516, EOST - Universite de Strasbourg (France), 4 - Department of Earth Science, Scientific Institute, University Mohammed V, 10106 Rabat, Morocco (Morocco), 5 - Department of Geological Engineering, Mugla Sitki Kocman University, 48000, Turkey (Turkey), 6 - Institut de Physique du Globe, CNRS-UMR7516, EOST - Universite de Strasbourg, F- 67084, France (France)

Abstract

The 2016 January 25 earthquake (Mw 6.3) follows in sequence from the1994 May 26 earthquake (Mw 6.0) and the 2004 February 24 earthquake (Mw 6.4) in the Rif Mountains and Alboran Sea. The earlier two seismic events which were destructive took place on inland conjugate faults, and the third event occurred on an offshore fault. These earthquake sequences occurred within a period of 22 yr at ?25 km distance and 11?16-km depth. The three events have similar strike-slip focal mechanism solutions with NNE-SSW trending left-lateral faulting for the 1994 and 2016 events and NW-SE trending right-lateral faulting for the 2004 event. This shallow seismic sequence offers the possibility (i) to model the change in Coulomb Failure Function (CFF with low ? including the pore pressure change) and understand fault-rupture interaction, and (ii) to analyse the effect of pore fluid on the rupture mechanism, and infer the clock-time advance. The tectonic loading of 19?24 nanostrain yr-1 obtained from the seismicity catalogue of Morocco is comparable to the 5.0 × 1017 N·m yr-1 seismic strain release in the Rif Mountains. The seismic sequence is apparently controlled by the poroelastic properties of the seismogenic layer that depend on the undrained and drained fluid conditions. The stress-rate ranges between 461 and 582 Pa yr-1 with a CFF of 0.2?1.1 bar. The computed clock-time advance reaches 239 ± 22 yr in agreement with the ?10 yr delay between main shocks. The calculated static stress change of 0.9?1.3 bar, under pore-fluid stimulus added with well-constrained geodetic and seismic strain rates are critical for any seismic hazard assessment.

Keywords: Seismicity and tectonics, Dynamics: seismotectonics, Fractures, faults, and high

strain deformation zones, Neotectonics

90

*Corresponding author Athmouni Malak <[email protected]>


S.07: SEISMICITY RATE INFERRED FROM GEOLOGY MODEL AND IMPLICATION IN PROBABILISTIC SEISMIC HAZARD ASSESSMENT, THE CASE OF GAFSA FAULT IN SOUTHWESTERN TUNISIA

Athmouni Malak 1, Ksentini Ahmed 2, Abbes Chedly 3

1 - PhD Student (Tunisia), 2 - assistant professor (Tunisia), 3 - Professor (Tunisia)

Abstract

This work aims to estimate the seismic occurrence rates for the case of Gafsa fault in south western Tunisia. The evaluation is based on the geological parameters of the active fault. Using the local earthquake catalog, the rates were estimated for different magnitude binsby deploying the appropriate techniques. Then, the geological data were drawn from the bibliography in order to plot the yearly recurrence curves by means of global empirical prediction models. A comparison between the seismicity rates inferred from the earthquake catalog and the predicted rates inferred from the slip rates is presented and some correlation are found. A sensitivity analysis is conducted to evaluate the impact of uncertainties in events location on the final estimates.

Keywords: seismic occurrence rate, Gafsa fault, active faults, earthquake catalog, slip rates

91

*Corresponding author Manzunzu Brassnavy <[email protected]>


S.07: TOWARD A HOMOGENEOUS MOMENT-MAGNITUDE DETERMINATION FOR EARTHQUAKES IN SOUTH AFRICA: ANALYSIS OF UNCERTAINTIES IN MAGNITUDE CONVERSION

Manzunzu Brassnavy 1 2, Brandt Martin 2, Midzi Vunganai 2, Durrheim Raymond 1, Saunders Ian

2

1 - University of the Witwatersrand [Johannesburg] (South Africa), 2 - Council for Geoscience (South Africa)

Abstract

Earthquake magnitude is the most important parameter in the catalogue for seismic hazard analysis. It is known that the only consistent measure of magnitude is based on the seismic moment. However, most catalogues especially historical ones do not report moment magnitude, but have other magnitude types like local magnitude Ml, body wave Mb and surface wave magnitude Ms. In this regards, we present a first attempt to derive an earthquake moment magnitude (Mw) ? Local magnitude (ML) relation for South Africa with a general orthogonal regression. This may be approximated by Mw ~ ML - 0.15 ± 0.15 for the magnitude range 3.6 ?ML? 4.8. We carried out spectral analysis on the vertical component seismograms assuming a Brune model for the S-wave source radiation from which Mw can be computed. Locally derived attenuation functions for both mining related and purely tectonic events were used in the calculations. We verified our relation by comparison with those reported by the National Earthquake Information Centre (NEIC) and CMT. The new formulae were used to homogenise the new Catalogue for Johannesburg to moment magnitude for the period between 1964 and 2016. This relation will be used in future in the practice of magnitude determination for South Africa.

Keywords: Catalogue, South Africa, local magnitude, Moment Magnitude, Uncertainties

92

*Corresponding author El Tahir Nada <[email protected]>

Poster: Earthquake Hazard Assessment https://afsc2018.sciencesconf.org/192229/

S.07: AN OVERVIEW OF: THE PROBABILISTIC SEISMIC HAZARD ASSESSMENT FOR SUDAN AND THE KHARTOUM SEISMICITY

El Tahir Nada 1, Midzi Vunganai 2

1 - University of Khartoum (Sudan), 2 - Council for Geoscience (South Africa)

Abstract

The seismic database used in this study consists of a regional catalogue. The catalogue was checked for completeness with respect to time and it was homogenised to a surface wave magnitude (Ms). Areal seismic zones were selected based on present day seismotectonic knowledge. The hazard calculations are done for rock sites. Since there are no ground motion prediction models for Sudan, we selected the SEA96 model, which was derived for extensional tectonic regimes similar to Sudan. In the results, regional hazard maps for 10% probability of exceedance in 50 years and 100 years were prepared. A maximum ground motion value of 0.2g was observed near the city of Juba for the hazard map of 10% probability of exceedance in 50years (i.e. return period of about 475years), and about 0.04g for Khartoum city from the hazard map of 10% probabilistic exceed dance in 50 years. Recently, the local seismic network around Khartoum, has recorded a few events. It is of particular interest to investigate the local seismicity around Khartoum in order to better establish the potential for large events, since a magnitude 5.5 event in Khartoum could be a disaster. Apparently, the area has a very low seismicity level with only a few local events per year, and there has not been any known events larger than Ml=4 since 1993. The long term seismicity rate is similar to the New Madrid area. The investigated seismic record and the calculations made in this work confirmed the presence of large geological structures which could support a large earthquake. Some of these structures are apparently seismically active. However, there is no evidence of historical large events. At the same time these small recent events are of great importance because they occurred close to the capital city, Khartoum.

Keywords: Hazard, sesimicity, Sudan.

93

*Corresponding author Hamidatou Mouloud <[email protected]>


S.07: EVALUATION DE L'ALÉA SISMIQUE DE LA RÉGION DE CONSTANTINE (NORD-EST ALGÉRIEN)

Hamidatou Mouloud 1, Mohammdi Yahia 1, Nassim Hellal 1

1 - CRAAG (Algeria)

Abstract

Le nord de l'Algérie a subi plusieurs séismes majeurs et destructifs dans son histoire en raison de sa position sismotectonique à la frontière des plaques lithosphériques africaine et eurasienne. Le nord-est du pays a particulièrement souffert des effets du séisme du 27 octobre 1985 (I0=VIII) qui a détruit une partie de la ville de Constantine et qui a causé la perte de plusieurs vies humaines. L'objectif de cet article est d'analyser l'activité sismique de la région du Constantinois entre 1357 et 2014. Notre recherche est une contribution à l'amélioration de la gestion du risque sismique en évaluant l'aléa sismique dans la région du Constantinois. Des études visant l'évaluation de l'aléa sismique de cette région ont été réalisées dans le passé. Dans ce travail, on se propose de présenter les derniers résultats d'une étude probabiliste d'analyser de l'aléa sismique où les données nouvelles de sismotectonique et de sismicité sont incorporées. Pour réaliser et visualiser la modélisation de l'input sismique dans les zones urbaines, l'évaluation de l'aléa sismique et l'etablissement d'un catalogue de sismicité nord-est algérien, des graphes et des cartes ont été conçus à l'aide d'un système d'information géographique (SIG), le code Z-MAP v. 6 et le logiciel CRISIS v. 2007.

Keywords: Aléa sismique, Zone source, Catalogue de sismicité, Accélération, Constantine,

SIG.

94

*Corresponding author Haou Youssef <[email protected]>


S.07: SISMICITE ET RISQUE SISMIQUE AU MAROC

Haou Youssef 1, Serroukh Mostafa 1, Ouazani Touhami Abdelouahed 1, Khald Hassan 2, El Mrihi Abdelaziz 1

1 - Département des Sciences de la terre Faculté des Sciences Tétouan, Maroc (Morocco), 2 - : Département de physique Faculté des Sciences Rabat, Maroc (Morocco)

Abstract

Le Maroc a été affecté durant son histoire par des séismes, les premiers séismes recensés ne sont connus que depuis le IXéme siècle. L'objet de ce travail est d'étudier l'impact des séismes sur l'Hommes sur ses biens et d'évaluer l'apport des données de la sismicité historique à la connaissance globale de celle du Maroc. Nous avons élaboré un catalogue sismique. Celui-ci nous a permis de réalisé des cartes de sismicité dont l'analyse révèle une concentration de foyers dans la partie nord du Maroc avec une direction dominante NE-SW et nous a permis aussi la mise en évidence d'une activité sismique. Cette sismicité est représentée par un coefficient b de l'ordre de 1.158 valeurs qui indique que les séismes de faible à moyenne magnitude sont relativement plus fréquents que les séismes de forte magnitude. Nous avons déterminé dix zones sources couvrant l'ensemble du territoire. La délimitation de ces zones sources s'est basée sur les données géologiques, tectoniques, géodésiques, géophysiques et géotechniques, et d'autre part de la sismicité historique et instrumentale et des mécanismes au foyer. Pour chaque zone source nous avons calculé les valeurs de a et b de la relation de Gutenberg-Richter, le taux annuel de l'activité sismique l, la répartition spatiale des séismes, la magnitude maximale Mmax et la profondeur maximale des foyers. En nous basant sur un modèle adéquat, nous avons calculé l'accélération du sol pour cette région avec une probabilité de 90% de ne pas être dépassé durant des périodes d'observation de 50, 100 et 250 ans. Les résultats du traitement des données sismiques sont représentés sous forme de courbes d'iso-valeurs des accélérations en % de g. Nous avons obtenus des cartes des accélérations permettant de limiter les zones à risque dans cette région.La valeur maximalede 16% de g a été observée dans la région d'Al Hoceima.

Keywords: Sismicité/ Zone Source/ Risque Sismique/ Catalogue Sismique/ Maroc/

95

*Corresponding author Azougay Abdellah <[email protected]>


S.07: IDENTIFICATION DES PARAMÈTRES SISMIQUES RELATIFS AU SOL DE LA RÉGION DU GRAND NADOR

Azougay Abdellah 1, Chaaraoui Aboubakr 1, Rezqi Halima 1, Chourak Mimoun 2, Oujidi Mostafa

1

1 - Applied Geosciences Laboratory (Morocco), 2 - Ecole nationale des sciences appliquées Oujda (Morocco)

Abstract

L'estimation de l'aléa sismique dépend des données géologiques, géotechniques (la détermination de certains paramètres physiques), données de sismicité historiques et de l'effet de site, Elle contribue considérablement à l'évaluation du risque sismique. Afin de déterminer quelques paramètres tel que la période fondamental du sol et l'accélération maximale prévisible, Des mesures relative au bruit de fond ont été réalisées afin de déterminer la période prédominante relatives aux différentes formations géologiques par l'application de la méthode H/V (Nakamura, 1989). Ensuite, nous avons fait une carte de modélisation montrant l'attribution des fréquences propres des différents points de mesures aux couches géotechniques de surface (30m de profondeur), L'intérêt de la détermination des conditions locales du sol est très important pour éviter le phénomène de résonance (amplification dynamique du sol) sur les sites constructible. Les résultats montrent que les fréquences de faibles valeurs caractérisent les formations géologiques récentes (Quaternaire), tandis que les fréquences élevées correspondent à la formation basaltique du Gourougou. Les résultats constituent un outil important pour l'élaboration du Plan de Prévention du Risque Sismique de la région d'étude et un outil d'aide de décisions au profit des institutions en vigueurs.

Keywords: sol, paramètres sismiques, méthode H/V

96

*Corresponding author Chabane Souhila <[email protected]>


S.07: SITE EFFECTS, AMPLIFICATION AND SOIL CHARACTERIZATION OF ALGIERS SEISMIC ZONE

Chabane Souhila 1 2 3 4

1 - Djamel Machane (Algeria), 2 - Fatma Khaldaoui (Algeria), 3 - El-Hadi Oubaiche (Algeria), 4 - Rabah Bensalem (Algeria)

Abstract

The Dar El Beida area, situated in the Mitidja basin, is characterized by its Plio-Quaternary sediments, bordered by 2 faults. Indeed, the analysis thanks to the spectral ratio H/V ambient vibration method confirms these assumptions. An electric resistivity tomography strengthened the results obtained from ambient vibration for site characterization. The results obtained from various H/V curves shows that the values of frequencies vary from 3.9 to 5.5 Hz with varying standards deviations of ± 0.2 to ± 0.6 Hz. From the analysis of the derived H / V curves. The slope obtained by the SSE from the H / V analyzes is 8.13%, it is a dip of 4.65, The other slope towards the NNE is 4.5% with a dip of 2.6 °. This enables us to raise an interface plunging slightly towards the N and the S, which could suggest the presence of a convexity. The strongest amplitudes of the H/V curves (>5) are observed in the NW part of the site, the weakest towards the SE. This means that the velocity contrast is stronger in the NW part. This latter signified also that the most unstable grounds or those amplifying from the seismic point of view are partly in the NW of the study area; on the contrary, less amplifying grounds are located in the SE. Thanks to the results of the electrical imaging profile, we could model our terrain and determine two different layers with a contrast in terms of resistivity. The upper layer has stretched sub-layers and the deep layer shows tight layers in terms of "equidistance". The bumps of this interface mean that the frequencies may vary slightly. Indeed, the frequency of 11.8 Hz reflects the surface layer determined at 4 m and which is visible on the electrical imaging profile.

Keywords: Site Effects, Amplification, Mitidja basin, H/V ambient vibration, electrical

imaging profile

97

*Corresponding author Nana Gaelle Vanessa <[email protected]>


S.07: PRELIMINARY STUDY OF SEISMIC HAZARD ALONG THE CAMEROON VOLCANIC LINE

Nana Gaelle Vanessa 1, Tokam Alain-Pierre 2

1 - University of Yaounde I (Cameroon), 2 - University of yaounde I (Cameroon)

Abstract

Earthquakes frequently occur along the Cameroon Volcanic Line (CVL), with magnitude raging between 2 and 6. These events are from tectonics and volcanic origins. An experiment called Cameroon Broadband Seismic Experiment (CBSE) was conducted in the country between 2005 and 2007. These data collected was used in this work to computed the seismic hazard and therefore highlight the most risky areas around the CVL. We focused our analysis on one year period going from January to December 2005. On these data, we applied a pass band filter with frequency ranging from 1 to 5 Hz, then we did the picking of the P and S first arrivals. This allows to locate earthquakes. The located events were distributed along the Congo Craton margin. This gives are update view of the Cameroon neoseismicity. From the seismicity map and seismic hazard computation, we distinguished four risky areas: The mount Cameroon area, considered like the most seismically active; Then the southern Cameroon area it's seismicity is associated to the Kribi-Campo fault and also the presence of Congo Craton known for its high magnitude tectonic activity; The area along the Sanaga fault is the third risk zone; and the last one is the western Cameroon characterized by a large fault network.

Keywords: seismic hazard, seismicity, first arrivals

98

*Corresponding author Kariche Jugurtha <[email protected]>


S.07: STRESS CHANGE AND FAULT INTERACTION FROM A TWO CENTURY-LONG EARTHQUAKE SEQUENCE IN THE CENTRAL TELL ATLAS, ALGERIA

Kariche Jugurtha 1 2, Meghraoui Mustapha 1, Ayadi Abdelhakim 3, Boughacha Mohamed Salah 2

1 - Institut de Physique du Globe, CNRS-UMR7516, EOST - Universite de Strasbourg, F- 67084, France (France), 2 - USTHB, Laboratoire de Geophysique, FSTGAT, B.P. 32 El Alia, 16111 Bab Ezzouar, Algiers, Algeria (Algeria), 3 - Department of Seismology Centre de Recherche en Astronomy Astrophysique et Géophysique (CRAAG) Route de l'Observatoire, Bouzareah 16000 Algiers, Algeria (Algeria)

Abstract

A sequence of major seismic events reaching Ms 7.3, with thrust faulting mechanisms, occurred from 1891 to 2003 in the central Tell Atlas of Algeria located along the Africa?Eurasia plate boundary. Previous neotectonic investigations show that earthquake faults of the central Tell Atlas have the potential to generate large magnitude earthquakes. We calculate the level of stress change that promotes the occurrence of a seismic sequence, taking into account the earthquake fault parameters, their uncertainties, the eastward earthquake migration, the seismicity rate change, and the interseismic strain accumulation. The computed coulomb failure function (?CFF) includes the seismicity rate and the stress transfer with fault interaction. The ?CFF modeling shows 0.1?0.8 bar increase on fault planes at 7 km depth with a friction coefficient ?? 0:4 with stress loading lobes on targeted coseismic fault zone and location of stress shadow across other thrust-and-fold structures of the central Tell Atlas. The coulomb modeling suggests a distinction in earthquake triggering between moderate-sized zones and large earthquake rupture zones. Following the 2003 earthquake, Global Positioning System, Interferometric Synthetic Aperture Radar, leveling studies, and aftershocks show that postseismic cumulative moment release amounts to 17.08%, which suggests an additional static stress change. In addition, the presence of fluid and related poroelastic deformation is considered as another parameter that favors stress increase and fault interaction. Modeling the stress change and fault interaction near major cities may contribute to a better constraint of the seismic-hazard assessment and risk mitigation in northern Algeria.

Keywords: Tell Atlas, Seismicity and tectonics, Fractures, faults, pore fluid flow

99

*Corresponding author Allali Sid Ahmed <[email protected]>


S.07: RAPID EARTHQUAKE DAMAGE ASSESSMENT OF BUILDINGS USING FUZZY LOGIC APPROACH: APPLICATION TO ALGERIAN BUILDINGS

Allali Sid Ahmed 1 2, Abed Mohamed 2, Mebarki Ahmed 1

1 - Laboratoire de Modélisation et Simulation Multi Echelle (France), 2 - Saâd Dahlab University [Blida] (Algeria)

Abstract

Major earthquakes represent important issues to authorities, earthquake damage assessment tasks must be carried out after such disasters quickly and accurately in order to evaluate and classify buildings. Usually, visual inspections of damaged buildings are performed by qualified inspectors, however, making decisions about buildings safety under such urgent conditions of the aftermath of destructive earthquakes is absolutely a complex and crucial process, inspectors report always difficulties to evaluate and derive suitable global damage levels for affected buildings. Hence, this paper presents a theoretical approach to support the decision-making process of inspectors during damage assessment tasks by processing the observed damages in buildings' components to derive global damage levels. The proposed approach is based on fuzzy set theory and weighted fuzzy rules, buildings' structural and non-structural components are considered as inputs (parameters) to derive global damage levels, weighed fuzzy rules are proposed and their weights values are calibrated according to the influence of each component under each damage level on the building's global damage level. A database of a prior earthquake in Algeria of more than 30K evaluation forms is used to calibrate and validate the proposed approach, the performance of the approach is analyzed by assuming three scenarios to derive global damage levels: 1) considering only the non-structural components as influencing parameters, 2) considering only the structural components as influencing parameters, 3) considering all building's components as influencing parameters. Results show that the approach was able to predict correctly about 69% of cases in the first scenario, 85% in the second scenario and almost 90% in the third scenario.

Keywords: fuzzy logic, building, damage assessment, earthquake, weighted fuzzy rules.

100

*Corresponding author Noura Hichem <[email protected]>


S.07: EVALUATION DES DOMMAGES STRUCTURAUX POST-SÉISMIQUES PAR LES RÉSEAUX DE NEURONES

Noura Hichem 1, Abed Mohamed 2, Mebarki Ahmed 3

1 - University Djilali Bounaama Khemis Miliana (Algeria), 2 - University Blida 1 (Algeria), 3 - University Paris-Est Marne-la Vallée (France)

Abstract

Le présent article consiste à étudier l'efficacité des Réseaux Neurones Artificiels (RNAs) pour une évaluation rapide des dommages structurels après un tremblement de terre. Deux groupes de paramètres sont pris en considération : le groupe de composants structurels (infrastructure, élément vertical, contreventement, toiture et dalles), le groupe de composants secondaires (éléments non structuraux : escaliers, remplissages extérieurs, composants tels que balcons, cheminées etc). L'analyse des paramètres du réseau neuronal (RNAs) adéquate, c'est-à-dire le nombre de couches cachées et les neurones ainsi que les fonctions d'activation, donne la meilleure combinaison des dommages des composants qui gouverne le dommage global d'un bâtiment. Un ensemble de bâtiments endommagés est extrait d'une base de données récoltée au cours d'un sondage post-séisme par des techniciens qualifiés (séisme de Boumerdes, Algérie : Mw = 6,8 ; tremblement de terre du 21 mai 2003). La comparaison entre les dommages prédits et observés montre que la meilleure architecture du réseau de neurones correspond à une couche cachée avec un nombre de neurones égal au nombre de composants de construction (c.-à-d. 4 ou 8 composants). Les prévisions du RNAs et les dommages globaux observés sont conformes à : 70% lorsque le dommage global des bâtiments est supposé être influencé uniquement par le groupe d'éléments secondaires (non structurels), 80% pour les bâtiments lorsque les dommages globaux sont supposés être influencés uniquement par le groupe structurel, et 87% lorsque les dommages globaux des bâtiments sont supposés être influencés par les deux groupes de composants de construction, c'est-à-dire les composants structurels et secondaires.

Keywords: réseaux de neurones, bâtiments, dommages, Tremblements de terre, évaluation

post

101

*Corresponding author Pule Tebogo <[email protected]>


S.07: VULNERABILITY/DAMAGE CURVES FOR MAJOR CITIES IN SOUTH AFRICA

Pule Tebogo 1, Fourie Christoffel 2, Kijko Andrzej 3, Midzi Vunganai 4

1 - Council for Geoscience (South Africa), 2 - Walter Sisulu university of technology (South Africa), 3 - University of Pretoria [South Africa] (South Africa), 4 - Council for Geoscience (South Africa)

Abstract

Southern Africa is considered a stable continental region in spite of several cases of reported earthquakes, which caused considerable damage and casualties particularly in the mining industry. Most buildings and structures in South Africa are not designed to resist any intensity of earthquake. Most architects, engineers and builders in South Africa do not consider seismic resistance as a design requirement. This is mainly because the region has not experienced any serious destructive earthquake in recent years.The most destructive earthquake recorded in South Africa is the Ceres earthquake of 1969. The earthquake with a magnitude of 6.3 occurred on September 29, 1969 in the Ceres-Tulbagh region of the Western Cape Province about 100 km northeast of Cape Town. Serious damage occurred to certain buildings in the area (amounting to a total of U.S. $24 million). The structural damage varied from almost total destruction of old and poorly constructed buildings to large cracks in the better-built ones, twelve people were killed and many more were injured. Another event that caused severe damage to infrastructure occurred on 09th March 2005 at Stilfontein near Klerksdorp.Recent years have seen at least four mining induced tremors causing significant damage (Welkom 1976, Klerksdorp 1977, Welkom 1989 and Carletonville 1992). Such events show that it is, indeed, necessary to take seismic events into account in the design of any infrastructure. Assessing and understanding the risk facing South African cities as a result of major seismic activity have been paid little attention. The main focus of this study is to develop the most suitable damage curves for major cities in South Africa. Therefore, the main results are damage curves for twelve of the most common building classes in South Africa, to show the extent of damage expected to a certain building class, with a certain earthquake magnitude.

Keywords: vulnerability, building classes, earthquake, structural damage

102

*Corresponding author Said Benchelha <[email protected]>

Oral: Geodynamics, GPS, InSAR and remote sensing https://afsc2018.sciencesconf.org/193070/

S.08: MAPPING OF LANDSLIDES BY INTERFEROMETRY RADAR CASE OF LANDSLIDES IN TAOUNATE PROVINCE IN NORTHERN MOROCCO

Said Benchelha 1, Hassnaa Chennaoui 1, Mustapha Hakdaoui 2, Omar El Kharki 3, Taoufik Benchelha 4

1 - GAIA Laboratory. Hassan II University. Aïn Chock Sciences Faculty (Morocco), 2 - LGAGE Laboratory Hassan II University. Ben M'sik Sciences Faculty (Morocco), 3 - Faculty of Sciences and Techniques (Morocco), 4 - BENYA DEVELOPMENT (Morocco)

Abstract

Northern Morocco is characterized by relatively young mountains experiencing a very important dynamic compared to other areas of Morocco. The dynamics associated with the formation of the Rif chain (Alpine tectonics), is accompanied by instabilities essentially related to tectonic movements. The realization of important infrastructures (Roads, Highways,...) represents a triggering factor and favoring landslides. Several methods can be used for landslide mapping, including Landsat 8 and Sentinel-1 radar imagery. In this paper, the SAR Differential Interferometry (DinSAR) technique was applied to a couple of SLC-sentinel-1 images to highlight terrain movements at a site in Taounate Province. Despite the unfavorable conditions for InSAR due to vegetation cover, radar remote sensing observations provide valuable information that can be used for the assessment of landslide risk at the study area level. An adaptive phase filtering process has been used to improve the coefficient of coherence. The results obtained have been validated by GPS mapping.

Keywords: DinSAR, Landslides, Interferometry, Sentinel1, Cartography, GPS, InSAR.

103

*Corresponding author Bouyahiaoui Boualem <[email protected]>


S.08: POTENTIAL FIELDS INTERPRETATION IN THE NW OF ALGERIA: EVIDENCES OF ACTIVE FAULTS AND UNDERGROUND STRUCTURE.

Boukerbout Hassina 1, Abtout Abdeslam 1, Yelles-Chaouche Abdelkarim 1, Bouyahiaoui Boualem

1

1 - Centre de Recherche en Astronomie, Astrophysique & Géophysique-Observatoire d'Alger. (Algeria)

Abstract

The NW of Algeria is known as one of the most seismic active zone in Algeria and the West Mediterranean region. It constitutes a key area to study neotectonics structures and their geodynamical context. Until now, there is a little information about existence of deep active faults, which generate this strong activity. Potential fields data (aeromagnetic and gravity) are an important resource of information on crustal structure. The aim of this work is giving a reliable geometry of the major faults relative to the kinematics of this region. The results obtained from various filtered maps (shaded relief, derivatives, upward continuation) of the magnetic and gravity data were used to generate a structural map of the studied area. Whilst the continuous wavelet and ridgelet transforms can help in automatic detection of elongated structures in 3-D both onshore and offshore, to estimate their strike direction, shape and depth. The short wavelength potential fields anomalies are related to volcanic rocks on the coast and to the basement in sedimentary basins. The long wavelength anomalies are associated mainly with deep E-W structures, limiting the basins. In the North, similar structures have been identified in the Mediterranean Sea. This work yields to a 3-D image of the region and confirms the existence of several faults, localized or inferred, from former geological studies.

Keywords: 2D and 3D imaging, deep structures, faults and contacts, structural map,

potential fields data, aeromagnetic and gravity anomalies, wavelet transform, ridgelet transform

104

*Corresponding author Yelles Abdelkarim <[email protected]>


S.08: PLIO-QUATERNARY TECTONIC INVERSION EVIDENCED ALONG THE ALGERIAN MARGIN

Yelles Abdelkarim 1, Aidi Chafik 1, Beslier Marie-Odile 2, Lamine Hamai 3

1 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria), 2 - Geoazur (France), 3 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria)

Abstract

The Neogene evolution of the western Mediterranean region has resulted from the break off of the ALKAPECA domain and the southward drift of the Kabylian blocks. From the two marine surveys conducted along the Algerian margin: the SPIRAL (September 2009) and the MARADJA (2003/2005 s), it is evidenced that after the opening of the several basins of the western Mediterranean region, a Plio-Quaternary tectonic inversion process have affected the Algerian margin. We present here the Plio-Quaternary inversion using the seismic data set collected during two surveys. Tectonic inversion is at the deep margin displays a flat-ramp compressive system in the deep sedimentary series, which emerges at the foot of the continental slope and marks the seaward limit of a P-Q basins perched at mid-slope. The south-dipping ramps are neo-formed structures, whereas the flats use inherited lithologic discontinuities (base of the Messinian evaporitic series, top of the acoustic basement). The inversion tectonic process explain the actual compressive stress regime of northern Algeria marked by the seismicity of this region.

Keywords: tectonic inversion, Algerian margin, seismic data

105

*Corresponding author Hamai Lamine <[email protected]>


S.08: AN INITIATION OF A SUBDUCTION ZONE ALONG THE ALGERIAN MARGIN: WHAT DOES THERMOMECHANICAL MODELING SAY?

Hamai Lamine 1, Yelles-Chaouche Abdelkarim 1, Petit Carole 2, Le Pourhiet Laetitia 3, Abtout Abdeslam 1, Déverchère Jacques 4

1 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria), 2 - Géoazur (France), 3 - Institut des Sciences de la Terre de Paris (France), 4 - UMR6538 Domaines Océaniques (France)

Abstract

North Africa is undergoing a slow compression deformation due to the convergence current African-Eurasian. The deformation occurs on the continental margin (Frizon de Lamotte et al., 2011), as evidenced by the active seismicity recorded both on land and at sea (Yelles-Chaouche et al., 2006). This margin can thus represent a transitional step between the parameters of active and passive margin (e.g., Jolivet et al., 2006). The latest studies (SPIRAL, 2009) show signs of active or recent compressive deformation along this margin and Isostatic anomaly models show that the Algerian margin has isostatic anomalies close to that of an active margin (Hamai et al., 2015). In this work, we try to answer two questions: I) which rheological and thermal parameters control the location of compressive deformations at the old passive margin toe ? II) Are these parameters suitable for long-term evolution of the North Algerian margin to mature subduction zone? To test the effect of thermal and rheological parameters on the tectonic inversion of a passive margin, characterized by a young hot oceanic area, adjacent to a colder continental continent, we use thermomechanical modeling (pTatin, May et al., 2014). These two domains are separated by an ocean-continent transition zone (OCT) in a configuration similar to the northern Algerian margin. Finally, we test the effect of a smooth thermal gradient between the ocean and the continent and a clear vertical line between oceanic and continental geotherms. Our model results indicate that the tectonic inversion may progress to subduction when the OCT plunges into the continent or to an indentation of the lower continental crust by oceanic lithosphere when the transition zone is vertical. In both cases, the localization of deformations at the foot of the margin occurs only when it is sufficiently heated by the adjacent oceanic domain.

Keywords: mechanical models, thermos, initiation of subduction, North African margin,

thermal and rheological parameters.

106

*Corresponding author Fatima Ezzahrae Al Makkassi <[email protected]>


S.08: ESTIMATION OF VERTICAL MOVEMENTS IN THE RIF MOUNTAINS (MOROCCO) USING PERMANENT GPS MEASUREMENTS, TIDE-ALTIMETRY AND SEISMICITY

Fatima Ezzahrae Al Makkassi 1, Tahayt Abdelilah 2, Fadil Abdelali 3, Abdellah Elkenz 1, Reilinger Robert 4 5, Angel Ciberia 6, Mourabit Taoufik 7, Harnafi Mimoun 8, Amar Mohamed 9 2

1 - Université Mohammed V-Agdal (Morocco), 2 - Université Mohammed V-Agdal (Morocco), 3 - GEOHYD Laboratory, Geology Department, Semlalia Sciences Faculty, Cadi Ayyad University (Morocco), 4 - Massachusetts Institute of Technology (United States), 5 - MIT Parsons Laboratory (United States), 6 - Real Instituto y Observatorio de la Armada (Spain), 7 - Faculty of Sciences and Techniques, Mohammed 1st University (Morocco), 8 - Seismic Waves and Earth Structure research unit, Scientific Institute, Rabat - Morocco (Morocco), 9 - Agence Nationale de la Conservation Foncière, du Cadastre et de la Cartographie (Morocco)

Abstract

The present-day horizontal movements in Morocco have been the subject of several studies using two decades of GPS measurements. These studies suggested models on the geodynamic processes in the western Mediterranean region. However, vertical component of the movements, often of smaller magnitude, are still poorly constrained. In this work we use permanent GPS measurements from 2009 to 2015 to estimate both horizontal and vertical components of tectonic movements in the Rif's domain. . The obtained GPS velocity field shows a low vertical movement as a subsidence of 1~2 mm/yr as indicated by 5 GPS stations (TETN, TANG, CEU1. HOCM, MELI). Moreover, ISGN station shows a very striking uplift about 4 mm/yr. The preliminary results disagree with geological estimates. On one side, the region between Tangier and Sebta is supposed to be affected by a quaternary uplift, on the other hand, the external zone of the Rif (ISGN) shows a quaternary subsidence. Meanwhile we aim to find a combination between GPS data and tide-altimetry data and seismicity in the Rif.

Keywords: Vertical movements, GPS, Tide, Altimetry, Seismicity Rif, Morocco.

107

*Corresponding author Bougrine Amina <[email protected]>


S.08: NEW CONSTRAINTS ON THE NUBIA-EURASIA PLATE BOUNDARY KINEMATICS FROM GPS MEASUREMENTS IN ALGERIA

Bougrine Amina 1 2 3, Yelles Karim 1, Calais Eric 3, Bellik Amar 1, Mahsas Abdelhakim 1, Terki Toufik 1

1 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria), 2 - Université Abou-Bakr Belkaïd Tlemcen (Algeria), 3 - Laboratoire de géologie de l'ENS (France)

Abstract

Northern Africa is the locus of significant seismicity as a result of the oblique convergence between the Nubian and Eurasian plates in the Western Mediterranean. However, the kinematics of plate boundary deformation in this region remains unresolved because of a lack of quantitative data in the Maghrebides, east of the Gibraltar strait and the Alboran domain. Here we present new results based on continuous GPS data from 54 sites of the Algerian REGAT network, which spans 1200 km along the Algerian coast and 300 km inland, with a mean inter-site distance of 100km. We processed the 2007-2017 REGAT data together with 34 IGS sites using the GAMIT/GLOBK software. The resulting velocity field shows the expected NW-SE convergence between Nubia and Eurasia increasing gradually from east to west. We computed 2D strain accumulation models along 3 profiles as well as a 3D kinematic model to estimate crustal block rotations and fault slip rates. The best-fit models show that a significant portion of the Nubia-Eurasia convergence is accommodated offshore along the Algerian margin on south dipping slip faults at shallow depths with a maximum amount offshore Algiers, consistent with results from recent offshore geophysical investigations. In the western half of Algeria, data and models show that strain is confined to the coastal area, possibly involving slip on Neogene basin faults. In the eastern half of Algeria, plate boundary deformation is more broadly distributed, with lower slip rates on the offshore fault system, significant slip on an E-W right-lateral strike-fault through the Tellian Atlas, and some shortening likely accommodated along the southern border of the Saharan Atlas. These results place new constraints on seismogenic faults in the western Mediterranean with direct implications for regional seismic hazard. Further research requires densifying the GPS measurements and possibly combining it with InSAR.

Keywords: Algeria, boundary kinematics, deformation, GPS

108

*Corresponding author Amponsah Paulina <[email protected]>


S.08: ACTIVE TRANSFORM FAULTS IN THE GULF OF GUINEA: INSIGHTS FROM GEOPHYSICAL DATA AND IMPLICATIONS FOR THE SEISMIC HAZARD ASSESSMENT

Meghraoui Mustapha 1, Amponsah Paulina 2, Bernard Paul 3, Ateba Bekoa 4

1 - Institut de Physique du Globe, CNRS-UMR 7516 (France), 2 - National Data Centre, National Nuclear Research Institute, Ghana Atomic Energy Commission (Ghana), 3 - IPG Strasbourg, CNRS-UMR 7516 (France), 4 - Institute of Geological and Mining Research, Yaounde, & Mount Cameroon Volcano Observatory, Cameroon (Cameroon)

Abstract

Although the seismotectonics of Western Africa show the occurrence of major earthquakes (e.g., 1636 southwestern Ghana, 1939 offshore Accra; 1945 Cameroon-Congo border; 1983 Gaoual-Guinea) and prominent offshore transform fault, there is no analysis of the region that links the continental active tectonics with the oceanic fault zones (FZ) of the Gulf of Guinea region. Our study shows first the mapping of main faults using the bathymetric, gravimetric and magnetic data. We also associate regional seismicity (historical and instrumental seismicity) with focal mechanisms according to the Seismotectonic Map of Africa *. In the oceanic domain, we identify four main seismogenic fault zones, the Charcot FZ, Romanche FZ, Saint Paul FZ and Arkhangelskiy FZ. All of these faults have experienced large (Mw ? 6) to major (Mw ? 7) earthquakes during the last 50 years. We also calculate strain rates on these faults from late Cretaceous (-85 Ma) to present times using paleomagnetic and seismic moment data. The strain rates show a first stable trend around 2cm/yr then accelerate to 4 cm/yr in the last 10 million years. The comparison of late Quaternary strain rates with geodetic strain rates shows an accumulation of seismic energy on the Saint Paul FZ. The accumulation of seismic energy could lead to the initiation of a 7 to 7.5 Mw earthquake along the fault. Our seismotectonic analysis suggests the links between oceanic and continental tectonics, with about 20° anticlockwise fault trend rotation especially on the Saint Paul FZ. The potential for the occurrence of large earthquakes in the Gulf of Guinea should be taken into account for a realistic regional seismic and tsunami hazard of the Gulf of Guinea.

Keywords: West Africa, transform faults, earthquakes, gravity, magnetic data

109

*Corresponding author Bouyahiaoui Boualem <[email protected]>


S.08: THE REACTIVATION CLUES OF THE EAST-ALGERIAN MARGIN

Bouyahiaoui Boualem 1, Sage Françoise 2, Abtout Abdeslam 1, Yelles-Chaouche Abdelkarim 1

1 - CRAAG (Algeria), 2 - Géoazur (France)

Abstract

In this work, we analyze the crustal structure of the eastern Algerian basin and its southern margin in the Annaba region (easternmost Algeria), from a set of geophysical data collected during the SPIRAL cruise in 2009, which included a wide-angle, 240-km-long, onshore-offshore seismic profile, multichannel seismic reflection lines, and gravity and magnetic data, complemented by the available geophysical data for the study area. We discuss the localization of the recent deformation related to the margin reactivation compared to the main lithospheric domains of the margin-basin system, in order to better understand the terms of the structural inversion. The analysis of seismic reflection profiles with different resolutions shows that the recent crustal deformation related at the reactivation of the northern Algerian border is mainly located in continental domain, at the necking zone, where the topographic gradient of the top and the base of the crust are strongest. On the edge of the deep basin, only the sediments would be engaged in the deformation, where the crustal faults of the necking zone emerge. Thus, this part of the margin would be the more deformable of margin-basin system, and would be sufficiently deformable to not transmit the deformation to the deep basin as well as hyper-thinned continental domain as the oceanic domain.

Keywords: Algerian basin, seismic data, deformation, geodynamic evolution

110

*Corresponding author Tahayt Abdelilah <[email protected]>


S.08: CURRENT STATE OF UNDERSTANDING OF TECTONICS IN MOROCCO FROM TWO DECADES OF GEODETIC OBSERVATIONS

Tahayt Abdelilah 1 2, Reilinger Robert 3, Floyd Michael 3, King Robert 3, Mourabit Taoufik 4, Koulali Achraf 5, Fadil Abdelali 6, Vernant Philippe <[email protected]> 7, Mazzotti Stephan 7,

Harnafi Mimoun 2, Rimi Abdelkrim 2, Amar Mohamed 8, Davila José-Martin 9, Pazos Antonio 9

1 - Centre National pour la Recherche Scientifique et Technique, Rabat, Morocco (Morocco), 2 - Scientific Institute, Mohammed V University of Rabat, Morocco (Morocco), 3 - Massachusetts Institute of Technology (United States), 4 - Faculty of Sciences and Techniques, Mohammed 1st University (Morocco), 5 - Australian National University (Australia), 6 - Cadi Ayyad University (Morocco), 7 - Université Montpellier 2 (France), 8 - Agence Nationale de la Conservation Foncière, du Cadastre et de la Cartographie (Morocco), 9 - Real Instituto y Observatorio de la Armada (Spain)

Abstract

Morocco is part of the complex convergence zone between the Africa and Eurasia plates. Convergence is associated with active shortening across the major mountain belts resulting in a high seismic risk. The 1960, Agadir M5.7 (12,000 deaths) and 2004, Al Hoceima M6.3 (629 deaths) earthquakes, while of moderate magnitude, are the most catastrophic contemporary seismic events in Morocco. Seismic hazard analysis requires understanding the mechanics of active deformation at the local and regional scale, with improved observations, integrating geodesy, geology and geophysics. We currently have a quite dense GPS network bringing together Moroccan, US, French and Spanish institutions. In total, there are about 20 permanent stations and 45 measurement points spread throughout Morocco. Fourteen other stations are presently being installed. Special attention has been focussed on understanding the mechanics of active deformation and the relationship to plate boundary processes in the Western Mediterranean. During two decades, many geodetic observations have been introduced to highlight the importance of active tectonics in Morocco: 1 GPS measurements since 1999 have defined the deformation pattern of tectonic blocks, including motion and deformation of the Rif ?block? and slow convergence across the High Atlas Mountains. A movement of 5.4 ± 1.5 mm/yr towards the SSW with respect to fixed Nubia was estimated in the central Rif block, and convergence across the Atlas of 1.6 ± 0.5 mm/yr. 2 Radar interferometry has been widely used in the study of the Rif deformation. This technique played a key role in the characterization of the co-seismic displacements of the 1994 and 2004 Al Hoceima earthquakes. In this presentation, we will update results from GPS observations throughout Morocco and across the Alboran Sea and southernmost Spain through 2017 to constrain better active deformation in the westernmost Nubia-Eurasia continental collision zone.

Keywords: Seismic hazard, active tectonics, Geodynamic, InSAR, GPS, Geodesy, Western

Mediterranean, Morocco

111

*Corresponding author Fadil Abdelali <[email protected]>


S.08: PRESENT-DAY VERTICAL DEFORMATION IN NEW ZELAND FROM TWO DECADES OF GPS DATA

Fadil Abdelali 1, Tenzer Robert 2, Almakkassi Fatimaezzahrae 3

1 - GEOHYD Laboratory, Geology Department, Semlalia Sciences Faculty, Cadi Ayyad University (Morocco), 2 - The Hong Kong Polytechnic University, PolyU, Department of Land Surveying and Geo-Informatics (China), 3 - Faculty of Sciences, Mohammed V University of Rabat, Morocco (Morocco)

Abstract

We investigate the relationship between present-day vertical crustal motion and tectonic block configuration. The study is conducted along the active tectonic margin between the Australian and Pacific tectonic plates in New Zealand with a well-defined tectonic block configuration. For this purpose, the rates of vertical crustal motions relative to the ITRF2008 reference frame are estimated based on processing the GPS data (provided by the GeoNET project) collected at 123 continuous GPS sites. The numerical results showed an uplift of the central Southern Alps at the current rate of 4.5 mm/yr. This tectonic uplift is coupled in the South Island by the subsidence on both sides of the Southern Alps. The detected rates of subsidence in the eastern South Island are typically less than 1 mm/yr. The subsidence in the Buller Region (in the northwest South Island) is 1.4?1.5 mm/yr. Except for the Taupo Volcanic Zone and the upper Raukumara Block (in the central and northeast North Island), the subsidence is prevailing in the North Island. The systematic subsidence up to 9 mm/yr is detected along the Dextral Fault Belt (in the lower North Island). The largest localized vertical displacements (between ?10 and 17 mm/yr) in the Taupo Volcanic Zone are attributed to active tectonics, volcanisms and geothermal processes in this region. A classification of these vertical tectonic motions with respect to the tectonic block configuration reveals that most of tectonic blocks are systematically uplifted, subsided or tilted, except for regions characterized by a complex pattern of vertical motions attributed to active geothermal and volcanic processes.

Keywords: GPS, tectonic setup, vertical crustal motion, volcanism

112

*Corresponding author Mahyoub Sulaiman <[email protected]>


S.08: FUSION SENTINEL-1 SAR WITH SENTINEL-2 OPTICAL TO EVALUATION AND MONITORING THE DYNAMICS OF TERRITORIES

Mahyoub Sulaiman 1, Rhinane Hassan 2, El Mehdi Monsour 2, Fadil Abdelhamid 3

1 - Geosciences Laboratory, Faculty of sciences Ain Chock Hassan II Univesity (Morocco), 2 - Geosciences Laboratory, Faculty of sciences Ain Chock Hassan II University (Morocco), 3 - Hassania School of Public Works (Morocco)

Abstract

The most important thing in remote sensing is to extract the valuable information through various satellite sensors that have different specifications. Image fusion allows the user to combine different spatial and spectral resolutions to improve the information for objectives such as evaluation and monitoring the dynamics of territories, newly the European Space Agency (ESA) lunched Sentinel-1 Synthetic Aperture Radar (SAR) and Sentinel-2 Multispectral Imager (MSI) sensors which have very different spatial and temporal resolutions (Sentinel-2 MSI sensor 10 m, 20 m and 60 m, nearly 5 days with 2 sensors; Sentinel-1 SAR sensor Stripmap 5 m, nearly 5 days with 2 sensors too). In this paper we investigate the fusion of SAR and optical for classification and mapping of dynamics of territories. Alhodaydah in western part in Yemen and alrachdia in eastern part in morocco were selected as a case study. The SAR image was terrain-corrected, speckle-filtered and co-registered to the simulated Sentinel-2 image. After radiometric and spatial resampling, the fused image stack was segmented and classified by SVM as proposed. Different fusion strategies are tested including fusion at the feature level and at the decision level. The analysis reveals that the best result can be obtained when the fusion of change information is carried out at the feature level.

Keywords: Remote sensing, dynamics of territories, ESA, SAR, MSI, feature level and feature

level

113

*Corresponding author Hakdaoui Sofia <[email protected]>


S.08: MULTISOURCE APPROACH FOR MONITORING SPATIAL POSITION AND MOISTURE/DRYNESS SURFACE INFORMATION OF WATER CAVITIES OF IMLILY SEBKHAT IN SOUTHWESTERN MOROCCO

Hakdaoui Sofia 1 2, Emran Anas 2

1 - Earth Observation Lab (Morocco), 2 - Earth Observation Lab (Morocco)

Abstract

Sebkhats zones represent a wet depressions in desert environments, they are generally considered as floodable wetlands of great environmental interest strongly linked to numerous environmental issues such as climate change, water quality, wildlife habitat and the biodiversity. The studies carried out recently by our team in the Sebkhat of Imlily in the south of Morocco, have shown that these geomorphological structures often contain the marks of the last climatic variations in the Sahara. The Sebkhat of Imlily represents a zone of intrigue to scientists, for cause more than 160 permanent water cavities, 0.4 and 4.6 m deep and the water has a salinity between 24 and 350g / liter, however it hosts life, many animals and fishes had been reported during a scientific field trip in January 2009. For this study, optical and radar images are used to contribute to understand the functioning of the Sebkhat through the discovery of underground hydrological networks. These data had contributed to the updating of the recent geological map made in 2012, by the Moroccan geological service. The main objective is to investigate and evaluate capability of the complementarity of multisensory optical data and SAR radar in this particular desert environment. Results have revealed that radar images are not only well suited to the study of desert areas, but also allow better monitoring of spatial position of water cavities in these flood zones. Their sensitivity to variations in slope of the topographic surface improves the geological and geomorphological analysis of these deserts zones.

Keywords: InSAR, Remote Sensing, Multisensor Optics, Sebkhat, Southern Morocco

114

*Corresponding author Aitelghazi Abdellah <[email protected]>


S.08: CONTRIBUTION OF THE THERMAL INFRARED BAND OF LANDSAT SENSORS (TM & ETM+) TO SPATIOTEMPORAL MONITORING OF SURFACE WATER TEMPERATURE ALONG THE AL MASSIRA LAKE BETWEEN 1987 AND 2017

Aitelghazi Abdellah 1, Rhinane Hassan 2, Bensalmia Ahmed 3

1 - AIT EL GHAZI (Morocco), 2 - RHINANE (Morocco), 3 - BENSALMIA (Morocco)

Abstract

Water remains a substantial resource that is threatened in its quality and quantity. Despite building new dams, Morocco will record a water deficit by the year 2025. This is mainly due to different natural problems affecting the reservoirs created by these dams that retain water. In this study we demonstrated the contribution of thermal infrared remote sensing to spatiotemporal monitoring of surface water temperature along the reservoir created by AL MASSIRA dam between 1987 and 2017. During this study we were able to represent the results on thermal and turbidity maps at several dates, illustrating the spatial distribution of surface water temperature since 1987. The thermal discrimination is noticed more precisely at the mouth of the reservoir, where the surface water temperature was more weakly distributed in 1984 than in 2017 since it became predominant in the same area of the reservoir. The analysis of the thermal data of TM6 band allowed us to create temperature maps illustrating the spatial and temporal distribution of this physical quantity along the reservoir. Thus, the correlations made between temperature and turbidity due to the presence of mineral matter and phytoplankton showed a strong positive correlation whose coefficient was estimated at 0.80 (R2). The linear equations deduced from this correlation allowed us to estimate and quantify the spatial distribution of the lake clarity as well as the density of suspended particles in water based on thermal infrared remote sensing data.

Keywords: AL MASSIRA lake, remote sensing, GIS, Landsat (5, 7), Sensor (TM & ETM +),

thermal infrared band 6.

115



S.08: SEISMOTECTONICS OF THE 2017 BOTSWANA EARTHQUAKE (MW 6.5): AN ACTIVE BRANCH OF THE EAST AFRICAN RIFT

Meghraoui Mustapha 1, Midzi Vunganai 2, Mohamed Saleh 1 3, Kwadiba Tarzan 4, Manzunzu Brassnavy 5 2, Mulabisana Thifhelimbilu 6, Pule Tebogo 6, Saunders Ian(6)

1 - Institut de physique du globe de Strasbourg (France), 2 - Council for Geoscience (South Africa), 3 - National Research Institute of Astronomy and Geophysics [Helwan] (Egypt), 4 - Botswana Geoscience Institute (Botswana), 5 - University of the Witwatersrand [Johannesburg] (South Africa), 6 - Council for Geoscience (South Africa)

Abstract

The 3 April 2017 Botswana earthquake occurred along a moderately seismic active zone in central southern Africa, west of the 2006 Machaze earthquake (Mw 7.0). Although located in the continental interior of the African plate, the seismogenic area previously considered as a stable region reveals a background seismicity associated with long-term deformation and faulting. We study the mainshock area using the seismotectonic data of the recent published map of Africa * and the Archean Limpopo?Shashe Tectonic Belt (ALSTB), the geodetic (InSAR) analysis and aftershock data determined from a post-earthquakelocal seismic array. The mainshock location (25.18E, 22.6S) and depth (25 +-3 km) provided by the Council for Geoscience (Pretoria), EMSC and USGS was followed by the largest aftershock with Mw 4.5 on the 5 April 2017. Our analysis of Sentinel-1 interferogram (ascending orbit) shows 4 to 6 cm coseismic slip on a NW-SE elongated and 30-km-long rupture consistent with the mainshock location, normal faulting mechanism and source time function (http://geoscope.ipgp.fr/index.php/en/catalog/). We also investigate the earthquake rupture dimension at depth from the inversion of surface deformation and obtain slip distribution on a fault plane striking 315°, dipping 45° and -80° rake and with Mo 7.12 e18 N.m. The rupture geometry is in agreement with the 500 aftershock locations and confirms the 28 km seismogenic thickness. The earthquake sequence affected the ALTSB that defines the central Limpopo belt. The ALTSB appears as an analog of the NE-SW trending Okavango active zone that experienced the Ml 6.7 earthquake in 1952. Although the seismic strainrate is of low level, the 2017 earthquake rupture characteristics and related seismotectonic framework classify the intraplate region as an active plate interior.

Keywords: Botswana, earthquake, InSAR, aftershocks, seismotectonics, continental interior

116

*Corresponding author Bouaziz Samir <[email protected]>


S.08: GEODYNAMIC FRAMEWORK OF THE NORTHERN AFRICAN MARGIN IN TUNISIA : IMPLICATION FOR SEISMOGENIC POTENTIAL

Bouaziz Samir(1) 2

1 - Ecole Nationale d'ingénieurs de Sfax, Département de Génie Géologique (Tunisia), 2 - University of Sfax, National Engineering School of Sfax, LR. ?Water-Energy-Environment? (Tunisia)

Abstract

The northern African margin in Tunisia is a privileged area for geodynamic reconstruction due to well identified morpho-tectonic domains (i.e., Tellian, Atlas belt, N-S axis, Eastern platform and Saharan platform). These domains resulted from a complex tectonic evolution that started with the beginning of Pangea break-up, and ended during the Cenozoic Alpine orogeny of the Maghrebide chain. The sedimentary cover was folded and faulted during main paroxysm episodes. Within the Africa-Europe convergence zone, Tunisia is marked by dominant tectonic features, including thrusting, strike-slip faults and folding ; it has major rupture zones that affect Quaternary deposit. In fact, most of Tunisian land is seismically active with significant historical and active deformations, showing recent seismic events. Tunisia is currently prone to a continuous seismotectonic activity actually represented by moderate seismicity magnitudes. The investigation has provided crucial information on the tectono stratigraphy history and seismotectonics in each domain which affect remote orogenic dynamics and the present-day state of the North African margin. Additionally, we analyze the organization of fracture systems and the movement in term of tensor stress and the evaluation the vulnerable areas. From Paleozoic to the present day, the geodynamic evolution is marked by several stages. Each stage showed a specific structuration related to the paleogeographic evolution of paleotethys, in the western margin of Tethys and the Mediterranean margin. The complex structural pattern of Tunisia resulted from the polyphased Cenozoic reactivation of inherited faults. The existing tectonic and structural information completed by the reconstruction of the succeeded of major tectonic events, allowed better understanding of the seismogenic zone related to the geodynamic African-Eurasia plate boundary. It was concluded that the main source of geodynamic activities in the Northern African plate in Tunisia is essentially caused by inter-plate deformations along major active faults.

Keywords: Keywords: African Margin, Tunisia, tectono, stratigraphy event, Active fault,

Seismogenic zone.

117

*Corresponding author Timoulali Youssef <[email protected]>


S.08: SEISMIC WAVE VELOCITY AND GEODYNAMIC EVOLUTION IN NW OF WEST AFRICAN CRATON : CASE OF THE MOROCCAN MESETA ? ATLAS DOMAIN

Timoulali Youssef 1, Jabour Nacer 2

1 - Institut scientifique, Université Mohamed V (Morocco), 2 - Institut vational de Geophysique- CNRST (Morocco)

Abstract

This study presents the outcomes of the local earthquake tomography applied in NW of West African Craton at the Moroccan Atlas domains. The arrival times data used in this study were obtained by the Moroccan seismic network. The seismic data (P and S wave arrival times) have been collected by 36 seismic stations located in the Atlas?Meseta domain for the period between 1988 and 2010. A linearized inversion technics and 3D modeling are used for determination of local velocity structure. A reconstruction of the geodynamic evolution is made by combining seismic tomography and geochronology. Local earthquake tomography technics allow us to obtain a deep velocity structures in the Atlas ? Meseta domain and accommodated new insights on imaging in detail deep geological structures. Analysis of seismic wave velocity was used to define and mapping main features of deep structure along northern margin of the West African Craton. Geodynamic evolution is discussed based on these deep structures and a geodynamical model is proposed to explain this evolution.

Keywords: Atlas Mountains, Seismic tomography, Lithospheric structure, Geodynamic

118

*Corresponding author Boulaassal Hakim <[email protected]>


S.08: CONTRIBUTION OF RADAR SATELLITE IMAGES IN RELIEF STUDYING IN THE PROVINCE OF AL-HOCEIMA

Boulaassal Hakim 1, Annaki Sara 2, El Kharki Omar 3

1 - Géoinformation et Aménagement du Territoire, FST_Tanger (Morocco), 2 - GAT, FST Tanger (Morocco), 3 - Géoinformation et Aménagement du territoire, FST Tanger (Morocco)

Abstract

The main objective of this article is to use the free radar data such as Sentinel-1 images, provided by the European Space Agency (ESA), to study the relief of Al-Hoceima province via radar interferometry technique. Two aspects have been studied through this study. The first one consists in exploiting the information contained in the phase of the Sentinel-1 radar images in SLC mode (Single Look Complex) to generate the Digital Terrain Model (DTM). For evaluation, the DEM generated from the Sentinel-1 images was compared to that derived from the SRTM (Shuttle Radar Topography Mission). After analysis, it turned out that the two products are complementary. The second aspect is to use the technique of differential interferometry (DinSAR) to detect the fine movements of the terrain and to create a map of displacement of the ground in the province of Al-Hoceima. This is a study of vertical displacements of soils, subsidence or upwelling. The results obtained by this technique indicate that it is indeed a recovery. These results suggest that this region is in compression, so elevation of soil levels. To validate this observation, it is possible to compare these results with geodynamic data in this region.

Keywords: Sentinel, 1, InSAR, Radar interferometry, DEM, DinSAR, soil displacement.

119

*Corresponding author Aguemoune Samir <[email protected]>


S.08: TROPOSPHERIC WATER VAPOR CORRECTION MODEL FOR INSAR USING ENVISAT/ASAR-MERIS DATA

Aguemoune Samir 1, Abdelhakim Ayadi 1, Belhadj-Aissa Aichouche 2, Bezzeghoud Mourad 3

1 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria), 2 - des Sciences et de la Technologie Houari Boumediène (Algeria), 3 - Universidad de Evora (Portugal)

Abstract

SAR (Synthetic Aperture radar) interferometry efficiency depends essentially on the reduction of errors effects. The atmospheric wet delay (AWD) and phase unwrapping play a key role in the interferometric process. This paper addresses a new method for AWD estimation based on ESA-ENVISAT/ASAR and auxiliary MERIS data. Usually this procedure is used under favorable conditions (small spatiotemporal baseline and relatively free-cloud conditions) In our study we focus on the possibility to use MERIS data under cloudy conditions. We propose a new algorithm for interpolation of water vapor in presence of clouds using a hybrid technique called 3D-IDW, based on Inverse Distance Weighted combined with a linear regression model. This method gives more realistic prediction of water vapor distribution in cloudy area by introducing beforehand, an appropriate cloud mask algorithm which reduces the effect of invalid reflectance and mixed pixels. The phase unwrapping method we used is from Aguemoune et al (2014) based on 2D-pseudocorrelation quality map and noncontinuous path unwrapping. Our procedure was tested on the Zemmouri area affected by a strong earthquake on may 21st 2003 Mw6.8 using a couple of ASAR single look complex (SLC) and MERIS level 2 product on the 65 descending track. The results show the existence of subsidence districts in agreement with those obtained in other studies.

Keywords: Interferometry, interpolation, Synthetic Aperture Radar (SAR), MERIS,

Deformation.

120

*Corresponding author Moussaoui Siham <[email protected]>

Poster: Geodynamics, GPS, InSAR and remote sensing https://afsc2018.sciencesconf.org/192968/

S.08: ETUDE ANALYTIQUE DES LINÉAMENTS MORPHO-STRUCTURAUX DU RIF CENTRAL (MAROC)

Moussaoui Siham 1, Azzouz Omar 1

1 - laboratoire de géologie appliquée;faculté des sciences;oujda (Morocco)

Abstract

La formation de la chaîne du Rif résulte d'une superposition de plusieurs phases de déformations qui se sont succédées depuis l'Oligocène jusqu'au Tortonien. Le façonnement de sa morpho-structure actuelle se rapporte à des mouvements tectoniques récents et actifs de moindres importances régies par la persistance du rapprochement Afrique Europe et les phénomènes épirogéniques des équilibres isostatiques. Cette activité néotectonique est animée par des déformations essentiellement cassantes relevant de la réactivation de toutes les structures géodynamiques préexistantes. Elle se traduit par l'alignement des traits morpho-structuraux, définis par des crêtes, des réseaux hydrographiques et des tracés de côtes. L'étude analytique de ces traits morphologiques nous permet de décrire des systèmes de linéaments bien définis qui se vérifient de manière comparable dans diverses localités. L'expression de ces agencements géométriques est défini vraisemblablement dans une organisation morpho-structurale contrôlée par des déformations essentiellement cassantes. Leur manifestation s'inscrit dans des relais de déformations régie en profondeur par une réactivation des structurations crustales.

Keywords: linéaments, morpho, structurale, rif central

121

*Corresponding author Radi Zohir <[email protected]>


S.08: SEISMIC ANISOTROPY OF NORTH ALGERIA FROM SHEAR-WAVE SPLITTING ANALYSIS

Radi Zohir 1, Yelles-Chaouche Abdelkrim 1

1 - Centre de Recherche en Astronomie Astrophysique et Géophysique (CRAAG) (Algeria)

Abstract

There are only few studies of internal deformation under Northern Africa; here we present such a study. We analyse teleseismic shear-wave splitting for the north part of Algeria, which improves our knowledge of lithospheric and asthenospheric deformation mechanisms in this region. The data are from several broadband (BB) stations that have recently been installed in this part of Algeria. This allows us to study waveform data generated by many tens of teleseismic events that were recorded at seventeen broadband stations. These stations cover thus a large area from the Tellian geological units in the North to the Saharian Atlas units in the South. Analysis of SKS-wave splitting results in significant spatial variations in fast polarization orientation, over scale length of 100 km and possibly less. The seismic anisotropy shows three clear spatial patterns observed at the stations. One pattern is a general ENE-WSW orientation observed for the subsurface under the stations in the North. This polarization orientation follows the direction of the Tell Atlas mountain chain, which is perpendicular to the convergence direction between Africa and Eurasia. Delay times vary significantly across the region, between 0.6 and 2 sec. At several stations there is an indication of a WNW-ESE polarization orientation, which is apparently related with a later geodynamic evolution phase of this region. A third pattern of seismic anisotropy emerges in the South, with roughly N-S orientation. We discuss the observations in light of geodynamic models and present-day geodetic motion.

Keywords: northeastern Algeria, anisotropy, Shear wave splitting, deformation

122

*Corresponding author Muhire Desire <[email protected]>


S.08: INTERFEROMETRY SAR ANALYSIS OF AL HOCEIMA (MOROCCO) DEFORMATION DUE TO A 6.3 MW EARTHQUAKES ON THE 25/01/2016 USING SENTINEL-1A IW.

Muhire Desire 1, Yassine Tounsi 1, Ahmed Siari 1, Hamid Bioud 1, Abdelkrim Nassim 1

1 - Chouaib Doukkali University (Morocco)

Abstract

SAR interferometry (InSAR) is an emerging field for the analysis of earth surface deformation with sub-centimeter accuracy. In this paper, we study the region of Al Hoceïma known for its dynamic seismic activity where several earthquakes were measured by the United States Geological Survey (USGS) in 2016 with magnitudes varying from 3.9 to a 6.3 Mw. We generate the interferometric products of the 6.3 Mw measured at 50km NNE of Al Hoceïma on the 25/01/2016 by using Sentinel-1 Interferometric Wide Swath Mode (IW) images, the InSAR processing based on the generic map tool (GMT5SAR) software and QGIS. The deformation map is obtained by the two pass differential InSAR between two SAR images where the master was acquired on January 10, 2016, and the slave on February 15, 2016, and a Digital elevation model by Shuttle Radar Topography Mission is used to remote the topography influence. We observed concentric fringes around the mountain region of Rif, and a high LOS displacement, (min: ?26.8 mm, max: +26.8 mm) regions near the epicenter. Our results are consistent with USGS ground data observation.

Keywords: Sentinel1, Radar, SAR, Interferometry, Deformation, Monitoring

123

*Corresponding author Elmortaji Nizar <[email protected]>


S.08: USING MAPPING DATA AND REMOTE SENSING TO GENERATE A 1/100 000 SCALE GEOLOGICAL MAP (AGDZ, MOROCCAN ANTI-ATLAS)

Elmortaji Nizar 1, El Kharki Omar 1, Boulaassal Hakim 1, Alaoui Yazidi Otmane 1, Fekkak Abdelilah 2

1 - Faculty of Sciences and Techniques, Tangier (Morocco), 2 - Faculty of Sciences, ChouaïbDoukkali University, El Jadida (Morocco)

Abstract

Given its mineral richness, the Moroccan Anti-Atlas had been given a special attention during the National Geological Mapping Program (PNCG). However, most of the geological maps realized cover essentially the Precambrian bedrock, thus the Paleozoic cover still contains several unmapped areas, and some detail work is still needed for some areas already mapped. On the other hand, geologists find multiple problems when realizing geological maps (limited access to exposures, reduced financial means, unfavorable weather conditions ...), which generates a heterogeneity and a discontinuity of the collected information. Remote sensing, with its ability to cover large areas and provide multispectral imagery, has proved its effectiveness in geological mapping at the Anti- Atlas.The aim of this work is using remote sensing to improve geological mapping, and mapping the uncovered areas of the Agdz sheet at a scale of 1/100000, basing on geological maps realized by the PNCG (Bouscour 1/50000 and Timidghas 1/50000), which will serve as a reference to check the lithostratigraphic subdivisions. The results obtained are integrated into a spatial database using spatial DBMS PostGreSQL-PostGIS.

Keywords: Geological mapping, AntiAtlas, Agdz, Remote sensing, Spatial Data Base PostGIS

124

*Corresponding author Alnahmi Fuad <[email protected]>


S.08: APPLICATIONS OF MULTISPECTRAL REMOTE SENSING TECHNIQUES TO UPDATE THE GEOLOGICAL MAP OF AL-MAGHRABAH AREA, HAJJAH PROVINCE, YEMEN

Alnahmi Fuad 1, Hilali Atika 2, Rhinane Hassan 3, Baidder Lahssen 4, Khanbari Khaled 5

1 - Fuad Al-Nahmi (Morocco), 2 - Atika Hilali (Morocco), 3 - Hassan Rhinane (Morocco), 4 - Lahssen Biadder (Morocco), 5 - Khaled Khanbari (Yemen)

Abstract

Remote sensing played an important role in the geological studies, interpretation and update the geological maps, remote sensing help in the collect and interpret of information about an object without physical contact with it. The aim of this study is achievement to update the geological map of the study area. The data utilizes is satellite image Sentinel-2, the processes used in this study, the OIF Optimum Index Factor is a statistic value that can be used to select the optimum combination of three bands in a satellite image. It's based on the total variance within bands and correlation coefficient between bands, PCA Principle component analysis is a statistical method under the broad title of factor analysis. The purpose of PCA is to reduce the large dimensionality of the data space (observed variables) to the smaller intrinsic dimensionality of feature space (independent variables), which are needed to describe the data economically. Sharpening is used to determine the edges and boundary of the lithology units, filtration also used to detect the geological structures like faults, folds, lineament and fractures in the area. The results obtained in this paper show that remote sensing was proved to be an effective tool in update the geological map of the region. Where there is a significant change in the distribution of rock units, structures and geological events compared to the previous geological map. The approach used in this study enables a great potential for lithological mapping, furthermore it gives the chance to update the old maps.

Keywords: Geological map, Sentinel, 2, OIF, PCA, Sharpening, Al, Maghrabah, Yemen

125

*Corresponding author Mukandila Ngalula Raphael <[email protected]>


S.08: IS THE NUBIA PLATE RIGID OR DIVIDED INTO SUB-PLATES? INSIGHTS FROM GEODETIC DATA AND THE SEISMOTECTONIC MAP OF AFRICA

Mukandila Ngalula Raphael 1 2, Masson Frederic 1, Meghraoui Mustapha 3

1 - EOST-Institut de Physique du Globe de Strasbourg (France), 2 - Research Center of Geophysics (Congo - Kinshasa), 3 - Institut de Physique du Globe, CNRS-UMR 7516 (France)

Abstract

Numerous geodetic studies have been carried out in recent years to characterize the kinematics of the African plate. Previous geodynamic and tectonic studies first led to the separation of the Africa plate into 2 plates, namely the Nubia plate to the west of the East African rift and the Somalia plate to the east. The subsequent densification of GPS data around the rift and related eastern tectonic blocks made it possible to subdivide the Somalia plate into several sub-plates (Somalia, Victoria, Rovuma and Lwandle). Nowadays, the density and quality of GPS data on the Nubia plate allow us to question its rigidity. Indeed, the recent seismotectonic map of Africa (*Meghraoui et al., 2016) shows that major tectonic structures and/or volcanic lines (e.g., Okavango, Cameroun) display significant seismicity and present-day active deformation. Can this seismicity be related to sub-plate boundaries within the Nubia plate? Using a GPS data synthesis and geodynamic analysis, we here question the possibility of defining 3 sub-blocks, i.e., the West Africa block, the Equatorial-central Africa block and the Southern Africa block. The African plate is characterized by geological shield structures made of basement rocks (mainly Proterozoic and Palaeozoic) where the seismotectonic activity and active deformation (inferred from GPS velocities) promote the sub-division and dislocation of the presumably rigid Nubia.

Keywords: Nubia, GPS, seismotectonics, plate tectonics

126

*Corresponding author Mohammedi Yahia <[email protected]>


S.08: APPORT DES IMAGES SATELLITAIRES ET DES MODÈLES NUMÉRIQUES DE TERRAIN À LA RECONAISSANCE ET LA CARTOGRPHIE DES STRUCTURES NÉOTECTONIQUE AU NE DE L'ALGÉRIE

Mohammedi Yahia 1 2, Hamidatou Mouloud 2

1 - Université des Sciences et de la Technologie Houari Boumediene [Alger] (Algeria), 2 - Centre de Recherche en Astronomie Astrophysique et Géophysique (Algeria)

Abstract

La cartographie des structures néotectonique est l'un des problèmes majeurs dans le domaine de l'évaluation de l'Aléa sismique, cette cartographie se fait auparavant par des techniques classiques comme le recours aux photos aériennes. Dans le cadre de ce travail on présente quelques applications des techniques de la télédétection moderne à la cartographie des structures potentiellement actives dans la zone de Constantine et ses alentours. Pour arriver à cet objectif on a utilisé les images satellitaires LandSat 8, Eo Ali et Orbview, ces images ont été rehaussées par un certain nombre de traitement et analyse pour extraire de l'informations structurales de façon rapide (ex: ACP, Filtrage, composions en fausses couleurs.). Cette analyse a été complété par une étude morphotectonique par le recours aux modèles numériques de terrain SRTM 30 et par l'analyse des formes de reliefs caractéristiques de la tectonique active. Les résultats de ce travail ont été synesthésie dans des cartes sismotectoniques qui contiens toutes les structures cartographiées avec une superposition de la sismicité de la zone. Toutes les données obtenues au cours de ce travail ont été intégrées dans une base de donnée SIG.

Keywords: Structures néotectonique, SRTM30, LandSat, télédétection, Algérie

127

*Corresponding author El Hafyani Mohammed <[email protected]>


S.08: LAND USE/LAND COVER IN SAISS PLAIN, USING REMOTE SENSING TECHNIQUES

El Hafyani Mohammed 1, Essahlaoui Ali 1, Mohajane Meriame 1, El Ouali Abdelhadi 1, El Hmaidi Abdellah 1, Van Rompaey Anton 2

1 - Université de Moulay Ismail (Morocco), 2 - Catholic University of Leuven (Belgium)

Abstract

The Saiss plain located in the center of Morocco, is one of the very important areas for agricultural practice with acceptable soil quality and a very large quantity of water resources. Recently, the management of these resources is unsustainable, on the one hand the overexploitation of water resources due to population growth and the development of industry, and on the other hand, the urban extension in agricultural areas, which offers a wide study to give and propose solutions to these problems. In this work, our main objective is to study land use/land cover changes in the Saiss Plain during the last 30 years, using remote sensing techniques based on the processing of satellite images with high spatial resolution. The multi-temporal maps of vegetation, soil, and soil moisture surfaces are created based on the analysis of spectral index; NDVI (Normalized difference Vegetation index), NDSI (Normalized difference soil index), and NDWI (Normalized difference Water index), using 4 Landsat TM images and one Landsat Oli Image acquired respectively in 1884, 1995, 2003, 2009, and 2017. The results show a decline in the vegetation surface of 83.97%, from 53381.52 ha in 1984 to 8559.47 ha in 2017, the soil surface decreased by 81.5% from 88510.61 ha to 15978 ha, and water surface has increased by 86.16% in the same period.

Keywords: Saiss plain, remote sensing, spectral index, NDVI, NDSI, NDWI.

128

*Corresponding author Chabane Sarah <[email protected]>


S.08: GEODYNAMIC EVOLUTION OF BOUKAÏS-EL AHMER AREA (NORTH BECHAR, SW ALGERIA) : USING REMOTE SENSING AND FIELD DATA

Chabane Sarah 1, Amri Kamel 1, Hamdidouche Rachid 1

1 - Université des Sciences et de la Technologie Houari Boumediene [Alger] (Algeria)

Abstract

The study area, extending from Boukaïs, to the West, to the western limit of Djebel Horeit to the East and from Ménabha to the North to El Ahmer village to the South. It is located at 40 km North of the city of Bechar in the South-western part of Algeria. The outcropping paleozoic formations are Cambrian to Carboniferous of age. The situation of this zone is complex regarding its position between two branches of the Southern Atlasic Fault. This major fault goes by the Boukaïs-Béni Zireg-Béni Ounif axis which seperates the Saharan Plateforme from the Occidental Saharan Atlas. The Boukaïs-El Ahmer formations are strongly deformed where the Devonian limestones remain the most affected.The results of the remote sensing analyses on « Landsat 7 ETM+ » and « Landsat 8 OLI » allowed us to discriminate the different lithologies and to draw a lineament map in which all the supposed fault trends are presented and which are confirmed by field data. In this study, we discuss the different constraint directions obtained by analyese of field data and present the different stages of the deformation since the Paleozoic.

Keywords: The paleozoic, Boukaïs, El Ahmer, North Bechar discriminate the different

lithologies, lineament map, analyese of field data.

129

*Corresponding author Smail Tayeb <[email protected]>


S.08: ESTIMATION OF LAND DEFORMATION IN OILFIELDS BY MEANS OF DINSAR, CASE STUDY IN-SALLAH, ALGERIA

Smail Tayeb 1, Abed Mohamed 1, Fatma Canaslan çomut 2

1 - Université de Blida 1, Faculté de Technologie (Algeria), 2 - Disaster & Emergency Directorate of Denizli (Turkey)

Abstract

The vertical deformation of surface at In Salah Gasfield is caused in part by the injection of CO2 and the production of Gas, The CO2 storage project has been in operation since 2004 with three horizontal wells into the water leg of the Krechba Carboniferous Sandstone gas producing with a reservoir thickness of 20m, and 1900 meters of depth. the amount of CO2 injected at the end of 2008 was 2.5 million tonnes. Its effects is clearly visible and it is produce a deformation signature at the earth's surface. The analyses of several data over In Salah Gasfield show a general trend of subsidence and uplift from the C band ENVISAT satellites.

Keywords: DInSAR, Deformation, Oilfield

130

*Corresponding author Allal Saddam Housseyn <[email protected]>


S.08: MEASURING DEFORMATION DUE TO 2016 NEW ZEALAND MW7.8 EARTHQUAKE BY USING GNSS PRECISE POINT POSITIONING TECHNIQUE

Allal Saddam Housseyn 1, Dekkiche Hichem 2, Bouguern Abderrahmane 3

1 - Space Techniques Centre and Earth Physics Laboratory of University of M'Hamed Bougara (Algeria), 2 - Department of Space Geodesy, Space Techniques Centre, Algerian Space Agency (Algeria), 3 - Earth Physics Laboratory, Faculty of Hydrocarbons and Chemistry, University of M'Hamed Bougara (Algeria)

Abstract

The main objective of this work is to evaluate the contribution of the GNSS (GPS & GLONASS) positioning technique in PPP (Precise Point Positioning) mode to study the coseismic displacements of 2016 New Zealand Mw7.8 earthquake. Relaxation of the coseismic stresses following an earthquake causes post-seismic crustal deformation, which may remain for days to years. Continuous monitoring of post-seismic deformation facilitates the understanding of the mechanism of deformation and post-seismic relaxation and viscous rheology. This work focuses on the processing of GPS and GLONASS observations with RTKLIB 2.4.2 software, developed at the University of Marine Science and Technology in Tokyo, Japan. Data of 182 stations of the permanent GNSS network GeoNet (Geological hazard information for New Zealand) are used. Positions time series analysis shows that four (04) stations (CMBL, KAIK, WITH and HANM) underwent a large displacement during the earthquake. The maximum is observed at the CMBL station, the displacements along the three directions (Northing, Easting and Up) are 2.28 m, 1.21 m and 0.88 m, respectively. These results show that the PPP method can be used successfully to estimate coseismic deformations caused by large earthquakes.

Keywords: GNSS PPP Timeseries Deformation NewZealand

131

*Corresponding author El Houyr Said <[email protected]>

Poster: Education, Outreach & Communication https://afsc2018.sciencesconf.org/192284/

S.09: THE IMPACT OF CLIMATE CHANGES IN THE WATER RESOURCES IN THE PLAIN OF THE GHARB (WESTERN NORTH OF MOROCCO)

El Houyr Said 1, Kachtali Mohammed 1

1 - Université Ibn Tofaïl (Morocco)

Abstract

Climate change is currently one of the phenomena that threatens both human societies and ecosystems in many countries around the world. Morocco, given its situation in the North West of the African continent, bordered by two maritime facades, is among the most vulnerable countries to the effects of climate change. Studies and simulations predict that this will have adverse consequences for the environment, particularly on surface and groundwater resources. This is due to the increase in temperature and the great variability of rainfall and the continuous increase in water demand. The Gharb plain, considered one of the most important water reservoirs in Morocco, is at the same time the largest irrigated perimeter of the country, from the agrarian point of view. Nowadays, this space has become fragile because of over-exploitation and the effects of climate change increasingly threatened it. The objective of this study was to investigate the relationship between climate changes and the water resources on the Gharb plain. This relationship expressed through two different types of impacts: on the one hand, the plain has affected by the lowering of the water table and on the other hand, it suffers the adverse effect of floods. To explain this complex situation, we have called for statistical indicators relating to climate and hydrology of the plain and to cartographic modeling using multifactorial analysis. This approach has led to the following preliminary results: from a statistical point of view, the Gharb plain has experienced, in recent years, succession of repetitive droughts periods and rainfall abundance periods. These results have led to a downward trend in the groundwater level due, in particular, to the agrarian intensification. Despite the state's efforts to limit this phenomenon, this situation of climatic irregularity has often led to catastrophic floods in Gharb.

Keywords: Climate change, water resources, cartographic modeling, drought.

132

*Corresponding author Taoufik Tbatou <[email protected]>


S.09: IDENTIFICATION SISMIQUE DE LA STABILITÉ D'UN BÂTIMENT DANS LA MULTI-PHASE NON LINÉAIRE PAR UN SYSTÈME DE CONTREVENTEMENT DE FRP

Taoufik Tbatou 1, Elyoubi Mohamed 2

1 - Ensa (Morocco), 2 - EMI (Morocco)

Abstract

Aujourd'hui, dans le domaine de la construction, la prise en compte des problèmes dynamiques est nécessaire pour garantir la fiabilité des structures dans les différentes applications, notamment dans le cas des structures soumises aux sollicitations sismiques. L'intérêt de ce travail est d'étudier les effets des matériaux composites utilisés dans le concept du contreventement pour un bâtiment sous le cadre des méthodes de dimensionnement en déplacement. En effet, un ensemble des bâtiments en béton armé, conçus en respectant les pratiques parasismiques usuelles, est utilisé de façon à étudier l'influence du contreventement, à base des plaques innovantes (FRP) par rapport celle du voile en béton armé, sur la stabilité de l'ouvrage lors d'un séisme. Plusieurs simulations numériques sismiques ont été conduites à fin d'identifier l'intérêt de différentes variantes à travers les indicateurs de dégradations partielle et totale de la superstructure.

Keywords: Séisme, stabilité, bâtiment, contreventement, dégradation, plaque FRP

133

*Corresponding author El Kilali El Hassan <[email protected]>


S.09: THE EDUCATIONAL SEISMIC STATION PRINCESS LALLA AICHA OF AGADIR

El Kilali El Hassan 1, Es-Saady Youssef 1

1 - Association Sciences of Life and Earth Souss (ASVTS) - Ibn Batouta School (Morocco)

Abstract

The Association for Life and Earth Sciences Souss (ASVTS) is a regional NGO created in 2002 in Agadir, Morocco. Active in the fields of environmental education and sustainable development, ASVTS started in 2013 a strategic project: A seismic station for educational purposes in Agadir. Its main objective is to inform and educate citizens about earthquakes and behaviors to adopt in seismic emergencies. Princess Lalla Aicha Stattion was therefore the first of its kind in Africa, in this city known for high seismic hazard. The earthquake of Agadir on February 29, 1960 (5.7 on the Richter scale), is considered the biggest natural disaster in Morocco in modern era with 12000 to 15000 victims, 25000 wounded and 90% of the city destroyed. After the disaster, the state made substancial efforts to reconstruct the city of Agadir. But the seismic risk is always there and from time to time, small tremors remind the inhabitants of the threat. Considering this reality, ASVTS and its partners have developed the project of the educational seismic station Princess Lalla Aicha. In five years, the objectives have been defined: to sensitize citizens to the natural phenomenon, to make the young "ambassadors" of the behavior that saves, to provide institutions with scientific and pedagogic support ... The station is operational and receives citizens of all ages and socio-professional backgrounds for sensitization, popularization of scientific sessions. To share this experience and its achievements, and to extend the horizon of our action with other insights, the meeting of Al-Hoceima is an opportunity for our seismic station to establish African ties.

Keywords: educational seismic station, Agadir

134

*Corresponding author Ivcevic Ante <[email protected]>


S.09: INDICATORS IN RISK MANAGEMENT : A FRESH PERSPECTIVE BETWEEN HAZARD ANALYSES AND SOCIETIES' RESPONSES

Ivcevic Ante 1 2, Mazurek Hubert 3, Siame Lionel 4

1 - Laboratoire Population-Environnement-Développement (France), 2 - Centre européen de recherche et dénseignement de géosciences de lénvironnement (France), 3 - Laboratoire Population-Environnement-Développement (France), 4 - Centre européen de recherche et d'enseignement de géosciences de l'environnement (France)

Abstract

To better assess the impact of natural risks (as earthquakes, but especially climate change impacts as landslides, marine submersions, floods...) on the environment and human societies, both the physical geological and social-economical sciences need strong synergies and interdisciplinary collaborations. This strong impetus will not only improve the understanding of environmental responses to natural and anthropological forcing factors but also strengthens risk assessment by establishing vulnerability indicators and societal resilience. Scientific researches on natural hazards that cross physical, environmental and social approaches are rare. In general, they often consist in a linear succession of different methodologies and analytical documents (hazard description, map of the risk, vulnerability maps, perception study) without a real integration of these different parameters in a global approach that is comprehensive for everyone. Risk is, however, a very cross-sectional domain because there is risk and vulnerability only if there is a potential impact on society. The scientific interest, and innovative part, of this thesis lies in the possible renewal of the concepts of each involved discipline and in a cross modeling of indicators that will allow the emergence of new problematic. This PhD thesis will mainly focus on Northern Morocco (Tangier-Tetouan). This region is characterized by high demographic and economic pressures (port and tourist infrastructures), which exacerbate the vulnerability of the coastal hazards (e.g., landslides, coastal erosion, floods). Lowering the buffering capacity of the beaches and dunes to climate variability, these pressures will necessarily negatively impact on any further coastal development. This PhD thesis aims at identifying reliable risk indicators and societal responses related to multiple risks (natural risk and climate change impacts) in order to provide a governance framework for the prevention of natural hazards in Morocco.

Keywords: risk, indicators, environement, hazard, society

135

*Corresponding author Shumba Blessing <[email protected]>


S.09: CURRENT STATUS OF THE ISC BULLETIN

Shumba Blessing 1

1 - International Seismological Centre (United Kingdom)

Abstract

The International Seismological Centre (ISC) was set up in 1964 to continue the work of ISS and BAAS. The main mission of the ISC is to analyse and distribute the Bulletin of earthquakes and other seismic events, which serves as the definite summary of global seismicity. To produce the Bulletin, the ISC collects parametric seismic data in the form of hypocentres and seismic phase arrival times, amplitudes and periods from over 150 agencies around the globe from both permanent and temporary seismic deployments. The ISC bulletin is the longest continuous, reliable uniform set of bulletin data. In addition to the global seismic bulletin production, the ISC is actively involved in important additional products and services, which include the ISC-GEM Global Instrumental Earthquake Catalogue, the ISC-EHB bulletin, the International Seismograph Station Registry, the IASPEI Reference Event List (GT), the ISC Event Bibliography, and the International Registry of Seismological Contacts. This presentation focuses on the current status of the ISC Bulletin, with special emphasis on collection of data from the African continent.

Keywords: ISC Bulletin, Global Seismicity

136

Alphabetical Index of Presenting Authors

A Aassoumi Habiba 74, Abacha Issam 35, Abdel-Aal Abdel-Aziz 12, Abdelouafi Abdallah 13, 27, Abed Mohamed 69, 99, 100, 129, Aberkan M'hamed 11, 18, 51, 55, Aboumaria Khadija 18, 50, 51, 55, 57, 58, Abtout Abdeslam 103, 105, 109, Afilal Tribak Abdelghani 70, Aguemoune Samir 119, Aidi Chafik 104, Aini Djamel 52, Aissa Saoussen 39, Ait Brahim Lahsen 27, 82, Aitelghazi Abdellah 114, Al Amin Ezat 36, Al Makkassi Fatima Ezzahrae

106, 111

Alaoui Yazidi Otmane 123, Allal Saddam Housseyn 130, Allali Sid Ahmed 99, Al-Mahfadi Afrah 72, Alnahmi Fuad 124, Alonso Belén 8, Amadio Claudio 80, Amar Mohamed 106, 110, Ammar Abdellah 37, Amponsah Paulina 41, Amri Kamel 108, Amri Kamel 17, 128, Andriamiranto Raveloson 25, 60, Angel Ciberia 106, Annaki Sara 118, Araújo A. Alexandre 32, Atalay Ayele 3, Ateba Bekoa 86, 108, Athmouni Malak 90, Ayadi Abdelhakim 6, 21, 98, 119, Azguet Roumaissae 37, 48, Azougay Abdellah 95, Azzouz Omar 8, 14, 120,

B Baby Patrice 4, Badreldin Hazem 38, Bahrouni Nejib 75, Baidder Lahssen 124, Bakkali Saad 46, Barazangi Muawia 2, Bekri Hachem 76, Beldjoudi Hamoud 30, 54, Belhadj-Aissa Aichouche 119,

Belhai Djelloul, 17, 22, Bellik Amar 107, Ben Sari Driss 2, Benaissa Zahia 28, 33, Benamri Sofia 18, 51, 55, Benbakhti Imene Meriem 22, Benchekroun Sabah 56, Benchelha Said 102, Benchelha Taoufik 102, Bendik Rebbeca 2, Bendjama Hichem 35, Benfadda Amar(3) 39, Benhamouche Azzeddine 59, Benmakhlouf Mohamed 8, Benouar Djilali 81, Bensalmia Ahmed 114, Bernard Paul 108, Beslier Marie-Odile 104, Bezzeghoud Mourad 21, 32, 39, 119, Bioud Hamid 122 Borges José 32, 34, 39, Bouaziz Samir 75, 78, 116, Boughacha Mohamed Salah 39, 98, Bougrine Amina 107, Bouguern Abderrahmane 130, Bouhadad Youcef 16, 17, Boukerbout Hassina 103, Boulaassal Hakim 118, 123, Boulahia Oualid 35, Boulanouar Abderrahim 31, Bourhili Amine 79, Bouskri Ghizlane 37, 48, Bouyahiaoui Boualem 103, 109, Brandt Martin 91,

C Calais Eric 107, Caldeira Bento 32, 34, 39, Canaslan çomut Fatma 129, Carvalho Joao 39, Casas David 8, Catalán Manuel 8, Cavalié Olivier 4, Cetin Esra 89, Chaaraoui Aboubakr 45, 95, Chabane Sarah 128, Chabane Souhila 96, Chaieb Ali 78, Chalouan Ahmed 8, Chami Adel 33, Chennaoui Hassnaa 102, Cherif Seif Eddine 69, Chimouni Redouane 39,

137

Chindandali Patrick R.n. 67, Chlieh Mohamed 4, Chourak Mimoun 8, 45, 69, 95,

D D'acremont Elia 8, Dahaoui Mohammed 13, Dahy Sayed 36, Dakki Mohamed 72, Davila Jose 2, 110, Dekkiche Hichem 130, Delouis Bertrand 30, Delvaux Damien 85, 88, Déverchère Jacques 105, Dhaha Faouzi 75, Dias Rui 39, Dib Assia, 21, Djenba Samir 20, Dobrynina Anna 31, Dridri Abdallah 83, Durrheim Raymond 25, 29, 60, 88, 91,

E El Abassi Mourad 76, El Fellah Younes 37, 48, 49, El Gabry Mohamed 19, 53, 80, El Hafyani Mohammed 127, El Hmaidi Abdellah 76, 127, El Houyr Said 131, El Khalidi Khalid 79, El Kharki Omar 102, 118, 123, El Kilali El Hassan 133, El Mahsani Abderrahman 13, 27, 82, El Mehdi Monsour 112, El Moudnib Lahcen 5, El Moussaoui Said 50, 51, 55, 57, 58, El Mrihi Abdelaziz 94, El Ouai Driss 26, El Ouali Abdelhadi 76, 127, El Tahir Nada 92, El Talibi Hajar 50, 51, 55, 57, 58 Elkailech Youssef 79, Elkenz Abdellah 106, Elmortaji Nizar 123, Elyoubi Mohamed 132, Emran Anas 73, 113, Ercilla Gemma 8, Es-Saady Youssef 133, Essahlaoui Ali 40, 76, 127, Estrada Ferran 8, Ezomo Friday 66,

F Fadil Abdelali 106, 110, 111 Fadil Abdelhamid 112, Fajri Zainab 57, Faried Ahmad M. 61, Farouk Mohamed 61, Fathi Badr-Eddine 70, Fekkak Abdelilah 123, Fiama Sylvanos B. 85, Floyd Michael, 2, 110, Fontiela Joao 32, 39,

Fourie Christoffel 101, Franco Vaccari 41,

G Galindo-Zaldivar Jesus 8, Ganza Gloire B. 85, Gil Antonio José 8, Gomez Francisco 2, Gorini Christian 8, Guessoum Nabila 16,

H Hakdaoui Sofia 73, 113, Hakdaoui Mustapha 102, Hamai Lamine 104, 105, Hamdache Mohamed 87, Hamdidouche Rachid 128, Hamidatou Mouloud 93, 126, Hamoudi Mohamed 21, Haou Youssef 94, Harbi Assia 10, Harnafi Mimoun 31, 37, 48, 106, 110, Hassan Hany 80, Hassoup Awad 24, Havenith Hans-Baalder 85, Hayashida Takumi 42, Hilali Atika 124, Hosny Ahmed 61, 63, Hussein Hesham 19, 42, 53,

I Idris Mouloud 39, Ito Takatoshi 25, Ivcevic Ante 134,

J Jabour Nacer 9, 117, Jele Vincent 64,

K Kachtali Mohammed 131, Kadiri Umar 66, Kariche Jugurtha 52, 89, 98, Khald Hassan 94, Khanbari Khaled 124, Khelif Mohamed Fadhlallah 28, 33, Kherroubi Abdelaziz 30, 54, Kijko Andrzej 101, King Robert, 2, 110, Korchy Hanan 55, Korrat Ibrahim 19, 53, Koulali Achraf 2, 110, Ksentini Ahmed 62, 84, 90, Kwadiba Tarzan 15, 64, 65, 115,

L Labraimi Ayoub 13, Lallout Imane 27, Lambarki Drissi Ibtissam 11, Lamdouar Nezha 40, Lamine Hamai 104,

138

Layadi Khalissa 47, Lazzar Ayoub 77, Le Pourhiet Laetitia 105, Lewi Elias 2, Liebenberg Bennie 25, Lukindula Jeanpy 88,

M Maamri Ridha 75, Mahsas Abdelhakim 107 Mahyoub Sulaiman 112, Makkaoui Mohamed 14, Maklad Mohamed 42, Mantsha Reuben 64, Manzi Musa 25, Manzunzu Brassnavy 29, 64, 91, Maouche Said 10, 17,19,22,53 Marimira Kwangwari 64, 68, Maritinkole Joseph 15, Masson Frederic 125, Mavonga Tuluka Georges 88, Mazurek Hubert 134, Mazzotti Stephan 110, Mbossi Eddy Ferdinand 86, Mcclusky Simon 2, Mebarki Ahmed 99, 100 Meghraoui Mustapha 1, 6, 19, 52, 53,

89, 98, 108, 115, 125

Mercier Jean-Luc 58, Merzougui Wissem 75, Midzi Vunganai 29, 43, 64, 91, 92,

101, 115, Mohajane Meriame 127, Mohammedi Yahia 126, Morad Taher 23, Mostafa Shaimaa 12, Moukchane Mohamed 74, Mourabit Taoufik 106, 110, Moussaoui Siham 120, Mphepo Felix 68, Mpuang Admore 15, 65 Muhire Desire 122, Mukandila Ngalula Raphael 125, Mulabisana Thifhelimbilu 43, 64, 115, Myendeki Sinovuyo 7,

N Naiji Zakariae 77, Nana Gaelle Vanessa 97, Nassim Abdelkrim 122, Nassim Hellal 93, Nobuoto Nojima 69, Noura Hichem 100, Ntibinyane Onkgopotse 15, 65,

O Ogasawara Hiroshi 25, Ogubazgi Ghebrebrhan 2, Oliveira Rui 32, Omar Khaled 36, Omira Rachid 50, Onstott Tullis 25,

Ouallali Abdessalam 74, Ouazani Touhami Abdelouahed

94,

Ouchen Ibrahim 37, Oujidi Mostafa 77, 95, Ousmana Habiba 76, Oussadou Farida 21, Ouyed Merzouk 39,

P Palomino Desiree 8, Panza Guliano 41, Pazos Antonio 110, Pelaez Jose 45, Petit Carole 105, Pule Tebogo 64, 101, 115

R Rabaï Ghilles 22, Radi Zohir 121, Rahmouni Abdelaali 31, Rathod Ganesh 64, Raveloson Andriamiranto 60, Rebai Noamen 78, Reilinger Robert 2, 106, 110, Rekik Dhouha 62, René Guiraud 17, Rengel Juan 8, Rezouk Ahmed 17, Rezqi Halima 77, 95, Rfifi Mohamed 82, Rhinane Hassan 112, 114, 124 Rimi Abdelkrim 110, Rindraharisaona Elisa 60, Ritz Jean François 17, 22, Romanelli Fabio 80, Romdhane Najla 84,

S Sadiki Abdelhamid 71, Sage Françoise 109, Salah Boughacha Mohamed 39, Salama Asem 19, 53, Saleh Mohamed 115, Sanz De Galdeano Carlos 8, Saunders Ian 64, 91, 115, Sayed Mohamed 80, Serroukh Mostafa 94, Shumba Blessing 68, 135, Siame Lionel 134, Siari Ahmed 121, Sigurjon Jonsson 2, Sitali Mako 64, Smail Tayeb 129, Smailhodzic Hrustem 44,

T Tabane Leonard 64, Tadili Ben Aissa 26, 82, Tadili Mehdi 26, Tahayt Abdelilah 2, 106, 110, Tahouri Jad 71, 83, Tahouri Ouassim 83,

139

Tavera Hernando 4, Tbatou Taoufik 132, Tenzer Robert 111, Terki Toufik 107, Tharwat Abdelfattah 42, Timoulali Youssef 37, 48, 89, 117, Tladi Bruno 65, Tlemcani Mohammed 27, 82 Tokam Alain-Pierre 97, Touati Mohammed 40, Toussaint Renaud 89,

V Van Aswegen Gerhard 64, Van Der Meijde Mark 65, Van Rompaey Anton 127, Van Wettum Arie 65, Vazquez Juan Tomás 8, Vernant Philippe 2, 110, Villegas Lanza Juan Carlos 4, Vitres Renier 2,

W Wachilala Piedade 34, Wahbi Meriam 70, Wassmer Patrick 58,

Y Yabe Yasuo 25, Yakubu Tahir 66, Yalaoui Rafik 39, Yassine Tounsi 122, Yelles Chaouche Abdelkrim 30, 54 Yokoi Toshiaki 42,

Z Zaghloul Mohamed Najib 18, 55, 58 Ziegler Martin 25, Zourarah Bendahhou 79, Zulu Brian 29, 64,

Acknowledgement

The Organizing Committee would like to thank its partners for their support

Official partners:

Gold partners:

Other partners:

Abstract Book of the 2nd General Assembly for the African Seismological Commission

Edited by Mourabit, T., El Talibi, H., El Moussaoui, S. & El kharki, O.

Published by Faculty of Sciences and Techniques of Al Hoceima Al Hoceima 04/2018

Cover, Design and Typeset by El Moussaoui S., Printed at Al-Hoceima (Morocco)

Number of copies: 150 First Edition

ISBN 978-9920-35-173-7

the moroccan isbn agency isbn 978-9920-35-173-7 of earth sciences jaume almera, barcelona spain...

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