m6.8 boumerdes, algeria earthquake of 21 may 2003 of 10 percent. m6.8 boumerdes, algeria earthquake...
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M E D I T E R R A N E A NS E A
ALGIERS Boumerdes
M'Sila
Medea
Djelfa
Bouira
BejaiaBlida
Ain Defla
Tiaret
Tizi Ouzou
Tipaza
Bourdj Bou Arrer
Batna
Boumerdes
Tissemsilt
Setif
Alger
Biskra
Medea
AKBOUBLIDA
M'SILA
Bouira
Hajout
Thenia
Azazga
Dellys
Mejidel
Guenzet
OuadhiaEl Arba
El Hamel
El Esnam
Palestro MicheletBaufarik
El Kseur
MirabeauStaoueli
Ain Taya
BOU SAADA
Chabounia
Boughzoul
El Afroun
Cherchell
Sidi-AissaAin Boucif
Ain Bessem
Ain Oussera
Bordj R'dir
Berrouaghia
Hassi Bahbah
Ain Khermane
Ain el Hajel
Dolfussville
Ksar-Chellala
Bouira Sahary
Teniet el Haad Ksar el Boukhari
Sour el Ghozlane
Tighzirt-sur Mer
BORDJ BOU ARRERIDJ
Ain ben Srour (Souk)
Map prepared by U.S. Geological SurveyNational Earthquake Information Center27 May 2003Map not approved for release by Director USGS
DATA SOURCES
EARTHQUAKES AND SEISMIC HAZARD USGS, National Earthquake Information Center NOAA, National Geophysical Data Center IASPEI, Centennial Catalog (1900 - 1999) Handbook of Seismology and Earthquake Engineering Global Seismic Hazard Assessment Program
PLATE TECTONICS Smithsonian Institution, Global Volcano Program
BASE MAP NIMA and ESRI, Digital Chart of the World USGS, EROS Data Center
GENERAL INTEREST PRODUCT XXXU.S. DEPARTMENT OF THE INTERIORU.S. GEOLOGICAL SURVEY
DISCLAIMER
Base map data, such as place names and politicalboundaries, are the best available but may not be current or may contain inaccuracies and thereforeshould not be regarded as having official significance.
Seismic hazard is expressedas peak ground acceleration(PGA) on rock or firm soil,in meters/sec, expected in a 50-yr period with a probability of 10 percent.
M6.8 Boumerdes, Algeria Earthquake of 21 May 2003
0 40 80 120 16020
Kilometers
SCALE 1:1,000,000
EXPLANATIONMain Shock
21 May 2003
Aftershocks 21 - 23 May 2003
M < 4.5
4.5 - 4.9
5.0 - 5.4
5.5 - 6.0
Boundary
Provincial
Urban Areas
Populated Places
Roads
Dual-lane and Divided
Secondary
Unpaved
Connector
Railroads
Airports
Active Civil
Active Military
Other Airfield
NORTHERN ALGERIA
21 May 2003 18:44:18.96 UTC36.879 N., 3.728 E.Depth 10 km (Geophysicist)Magnitude = 6.8 (USGS)
This earthquake occurred in early evening of 21 May just offshore ofthe coastal city of Boumerdes approximately 50 km east of the Algeriancapital of Algiers. Press reports indicated that the death toll was greater than 2200 with more than 6,000 injured and many more thousands home-less. The greatest loss of life was in and around the cities of Boumerdes and Thenia and in poorer neighborhoods of Algiers, due principally to the catastrophic collapse of concrete and masonry structures. Although powerand telephone outages and structural failure were reported in Algiers, the city was spared the devastation farther east. There were reports of a 7 - ft sea wave that damaged or destroyed 150 boats in the Spanish Balearic Islands, about 280 km north of Algiers. There also reports that underwatertelecommunications cables were ruptured by the earthquake.
4 3 2 1 0 1 2 3 4 5 6 7 8 9
10
4 3 2 1 0 1 2 3 4 5 6 7 8 9
10
32
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M E D I
T E R R
A N E A N
S E A
T e l l A t l a s
S a h a
r a n
A t l a
s
H i g h
P l a
t e a u s
G r e a t
W e s t e
r n E
r g
G r e a
t E a s
t e r n
E r g
S P A I N
M O R O C C O
A L G E R I A
T U N I S I A
Algiers
A F R I C A N P L A T E
E U R A S I A N P L A T E
Plate Tectonic Setting
EPICENTRAL AREA
5 mm/yr
6 mm/yr
19971992
1992 1995199919931994 19851982
198119801975
199819731973
2000
1988 19851994
197719742000
19781994 20021993 1996
200219541884
RELATIVE PLATE MOTIONS
The relative motion of adjacent tectonicplates is depicted on the map by short vectors located at selected locationson the plate boundary. In this present-ation, one plate is assumed to be rigid and fixed. The vector therefore repre-sents the direction of the moving platerelative to the fixed plate. The rate of relative motion is labelled next tothe vector.
The components of the vector perpen-dicular and parallel to the plate margin approximate convergent/divergent and transverse direction of motion between the plates, respectively. As viewed from the fixed plate, an inward directed com-ponent suggests convergence at and near the plate boundary that may be ex-pressed as crustal folding, uplift, thrustfaulting, or plate subduction. Similarly, an outward directed component sug-gests plate divergence such as would be expected at a zone of crustal spread-ing. Transcurrent or transform faultingwould be expected when the predom-inant vector component is parallel to theplate margin.
Epicentral Area
4 3 2 1 0 1 2 3 4 5 6 7 8 9
10
4 3 2 1 0 1 2 3 4 5 6 7 8 9
10
32
33
34
35
36
37
38
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M E D I
T E R R
A N E A N
S E A
T e l l A t l a s
S a h a
r a n
A t l a
s
H i g h
P l a
t e a u s
G r e a t
W e s t e
r n E
r g
G r e a
t E a s
t e r n
E r g
S P A I N
M O R O C C O
A L G E R I A
T U N I S I A
Algiers
A F R I C A N P L A T E
E U R A S I A N P L A T E
Earthquake History of Northern Algeria and Vicinity
EPICENTRAL AREA
19971992
1992 1995199919931994 19851982
198119801975
199819731973
2000
1988 19851994
197719742000
19781994 20021993 1996
200219541884
4 3 2 1 0 1 2 3 4 5 6 7 8 9
10
4 3 2 1 0 1 2 3 4 5 6 7 8 9
10
32
33
34
35
36
37
38
32
33
34
35
36
37
38
M E D I
T E R R
A N E A N
S E AS P A I N
M O R O C C O
A L G E R I A
T U N I S I A
Algiers
A F R I C A N P L A T E
E U R A S I A N P L A T E
Generalized Seismic Hazard
EPICENTRAL AREA
Eastern
Djelfa
El OuedEl Bayadh
Naama
Ouargla
Tiaret
Quibili
Biskra
Laghouat
M'Sila
Andalucia
Batna
Ghardaia
Tebessa
Medea
Centre-North
Saida
Tatawin
Setif
TlemcenKhenchela
Qafsah
QabisTawzar
MilaChlef Al Kaf
Murcia
Al QasraynMascara
Bechar
Bouira
Bajah
Sidi Bu Zayd
SkikdaBejaia
Silyanah
Sidi bel Abbes
Guelma
Ain Defla
Relizane
Jijel El Tarf
Banzart
Oum el BouaghiOran
Souk Ahras
Al Qayrawan
BlidaJundubah
Tipaza
Tizi Ouzou
Tissemsilt
Bourdj Bou ArrerMostaganem
Constantine
Annaba
Ain Temouchent
Centre-South
Zaghwan
AryanahBoumerdes
Safaqis
Safaqis
Madaniyin
Valenciana
Bin 'Arus
0 100 200 300 40050
Kilometers
SCALE 1:6,000,000
SCALE 1:6,000,000
0 100 200 300 40050
Kilometers
0 100 200 300 40050
Kilometers
SCALE 1:6,000,000
DISCUSSION
The earthquake occurred in the boundary region between theEurasian plate and the African plate. Along this section of the plate boundary, the African plate is moving northwestward against the Eurasian plate with a velocity of about 6 mm per year. The relative plate motions create a compressional tec-tonic environment, in which earthquakes occur by thrust-faulting and strike-slip faulting. Analysis of seismic waves generated by this earthquake shows that it occurred as the result of thrust-faulting.
Algeria has experienced many destructive earthquakes. On October 10, 1980, the city of El Asnam (formerly Orleansville and today Ech-Cheliff) was severely damaged by a magnitude 7.1 earthquake that killed at least 5000 people. The site of El Asnam is situated approximately 220 km to the west of the rec-ent earthquake. The same city, as Orleansville, had been heav-ily damaged on September 9, 1954, by a magnitude 6.7 earth-quake that killed over 1000 people. On October 29, 1989, a magnitude 5.9 earthquake struck about 110 km to the west of the recent earthquake and killed at least 30 people.
EXPLANATIONMain Shock
21 May 2003
Earthquakes Pre-1900
6.70
Earthquakes 1900 - 1972
5.6 - 6.0
6.1 - 7.0
7.1 - 8.0
Earthquakes 1973 - 2003
5.00 - 6.00
6.01 - 7.00
7.01 - 8.00
Plate Boundary
Convergent
EXPLANATIONMain Shock
21 May 2003
Earthquakes Pre-1900
6.70
Earthquakes 1900 - 1972
5.6 - 6.0
6.1 - 7.0
7.1 - 8.0
Earthquakes 1973 - 2003
5.0 - 5.9
6.0 - 6.9
7.0 - 8.0
Plate Boundary
Convergent
EXPLANATIONMain Shock
21 May 2003
Plate Boundary
Convergent
Political Boundary
International
Provincial
Seismic Hazard
0.0 - 0.2 m/sec
0.2 - 0.4
0.4 - 0.8
0.8 - 1.6
1.6 - 3.2
> 3.2 m/sec