appendix j merging catalogues with focus on the period 1975-2008 · 2010. 3. 30. · this document...

PRP – ECOS-09 catalogue Appendix J -Version 30/03/10

Appendix J

Merging catalogues with focus on the period 1975-2008

Authors: J. Woessner, P. Kästli, D. Eberhardt

Summary

This Appendix describes 1. in Section 1: catalogue data from all agencies providing data to be included for the

instrumental period 1975-2008 in ECOS-09;2. in Section 2: A comparison of catalogues from agencies of the various nations

providing data for the same region 3. in Section 3: The strategy and rules how catalogues from different sources are merged

to one catalogue of the instrumental period, in particular the definition and search of multiple entries describing the same earthquake together with quality assessment and assurance procedures.

This document focuses on the period 1975-2008, however, includes catalogues that span larger time periods (CPTI04, CENEC). These two catalogues both cover long time periods and in particular provide information from specific studies of moderate to large magnitude events (Mw ≥ 4.5 and Mw ≥ 3.5). Therefore, some of the entries of these catalogues become primary entries in the ECOS-09 database.

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1. Catalogue data description

Section 1 describes the requests and the obtained data from the agencies listed in Table 1.

1.1 Cataloguerequests from adjacent seismic networks / institutions

From the adjacent national seismic networks operators and authoritative national agencies, we requested updates and new releases of parametric earthquake catalogues including time, location, original and derived magnitudes, available intensity information, associated uncertainty parameters and available documentation. Details of what data we requested and what we received is described in the following paragraphs. Table 1 provides an overview of the catalogues: entries with white background are catalogues requested for ECOS-09, entries with light grey background indicate catalogues requested for ECOS-02.

In the following we describe the request, the parameters of the received data and display a seismicity map, a cumulative number of earthquakes as a function of time, a magnitude-time

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Table 1: Overview of catalogues to create ECOS2009. Light gray indicates catalogues received for generation of ECOS2002. For details refer to Fäh et al. (2003), SED (2002) that can be dowloaded from http://histserver.ethz.ch/publications_d.html.

Country Short name Institution Period Date of receipt ContactCH SED09 SED 1975-2008 N. DeichmannCH SED02 SED 1975-2001CH MECOS02 SED 1021-1997

D BGR68-07 BGR 1968-2007 25/02/2009 W. Henger

D BGR01 BGR 1968-2001 W. Henger

D BGR01-Macro BGR 813-1995 G. LeydeckerD LED09 LED 1996-2007 25/02/2009 W. BrüstleD LED02 LED 1995-2000 W. BrüstleD KA-GPI K. BonjerD CENEC GFZ 1013-2004 08/04/2009 G. Grünthal

F BCSF09 BCSF 1964-2009 03/03/2009 C. NicoliF LDG01 LDG 1962-1999 M. Nicolas, Y. MenechalF IPSN J. LambertF SisFrance BRGM 858-1999 J. Lambert

I CSI1.0 INGV-Rome 1975-2002 F. MeleI CSI1.1 INGV-Rome 1981-2002 F. MeleI CSI09 INGV-Rome 2002-2003 23/02/2009 F. MeleI BOLLSI INGV-Rome 2003-2005 23/02/2009 F. MeleI ISIDE INGV-Rome 2005-2007 23/02/2009 F. MeleI CPTI04 INGV-Milan M. StucchiI NT4_1_1 INGV-Milan 1005-1992 M. StucchiI CSI INGV 1975-2001 di Bona

A ZAMG09 ZAMG 1980-2009 04/03/2009 W. LenhardtA ZAMG02 ZAMG 1201-2001 W. Lenhardt


stem plot and a frequency-magnitude distribution of these catalogues. We use the agency specific local magnitude ML for display that is not the same as the local magnitude of the Swiss Seismological Service ML(SED).

1.2 Germany: Analysis of received catalogues

1. BGR catalogue (BGR09)

We requested the earthquake catalogue from the Bundesanstalt für Geologie und Rohstoffe (BGR) to regional earthquake catalogue, including date, time, location, depth, and original

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Figure 1: Overview of catalogue data received from BGR. Map of all events (top left), cumulative number versus time (M ≥ 1.95, top right), event magnitudes as function of time (bottom left) and (non)-cumulative frequency magnitude distribution (botttom right).


magnitudes as well as derived magnitude estimates, and the associated errors of the different parameters, in case they are available. The request was for the following extract of the catalogue: All events with M ≥ 2.0 in the region 47°-51°N and 5°E-13°E in a time span from 1968 until the end of 2007. Figure 1 displays the map of events, a cumulative number of events versus time, a magnitude of event versus time plot and the (non-) cumulative frequency magnitude distribution of the entire data set. Table 2 lists the original parameters and the corresponding parameters in the ECOS database. Quarry blasts are indicated in the catalogue. Table 3 shows the labeling of entries in the BGR catalogue and how these labels were translated into ECOS-09 event types.

BGR abbreviation

BGR explanation ECOS09 eventtype:

uk unknown [no such event cited]ke known earthquake EARTHQUAKEse suspected earthquake EARTHQUAKEkr known rockburst MINE_COLLAPSEsr suspected rockburst [no such event cited]ki known induced event INDUCEDsi suspected induced event INDUCEDkm known mine explosion EXPLOSIONsm suspected mine explosion EXPLOSIONkx known experimental explosion [no such event cited]sx suspected experimental explosion [no such event cited]kn known nuclear explosion [no such event cited]sn suspected nuclear explosion [no such event cited]ls landslide [no such event cited]gm [missing in legend] OTHER_EVENT[empty field] [missing in legend] EARTHQUAKE

Table 3: Entry definitions in the BGR catalogue and how these are translated to the ECOS-09 event types.

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Table 2: ECOS database parameter, original parameters of the BGR catalogue, description and range of data. The bulletin uses the IMS1.0 format discription.

ECOS Parameter Description RangeMin Max

Date ev_date Year 1968 2007Date ev_date Month 1 12Date ev_date Day 1 31Time ev_time Hour 0 23Time ev_time Minute 0 59Time ev_time Second 0 59Lat Lat Latitude [degree] 47 51Lon Lon Longitude [degree] 5 13Dep Dep Depth [km] 0 40

dep_co Depth commentAgency source Source

ev_type Event Typemag Magnitude 2 5.9


2. LED catalogue (LED09)

We requested an update of your regional earthquake catalogue from the Landeserdbebendienst Baden-Württemberg (LED). We asked for an extract of the complete catalogue in the time span of 1996 to the end of 2007. Figure 2 gives insight in the received data in the space, time and magnitude domains.

Data from the year 1994-1996 was taken from the catalogue as described in SED (2002). Detailed description of the seismicity is published on the web-site of the LED at:http://www.lgrb.uni-freiburg.de/lgrb/Fachbereiche/erdbebendienst/jahresbulletinsOriginal parameters and corresponding ECOS data base parameters are found in Table 4.Quarry blast are removed from the catalogue, they are not indicated.

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Table 4: ECOS database parameter, original parameters of the LED catalogue, description and range of data.


Date ev_date Year 1996 2007Date ev_date Month 1 12Date ev_date Day 1 31Time ev_time Hour 0 23Time ev_time Minute 0 59Time time_sec Second 0 59Lat Lat Latitude [degree] 45.51 48.30Lon Lon Longitude [degree] 5.94 11.05Dep Dep Depth [km] 1 33

dep_comm Depth commentMagnitude mag Magnitude 0.2 5.5

mag_type MLAgency source Source LED

http://www.lgrb.uni-freiburg.de/lgrb/Fachbereiche/erdbebendienst/jahresbulletins


3. The unified catalogue of earthquakes in central, northern, and northwestern Europe (CENEC)

We asked Prof. G. Grünthal (GFZ Potsdam) to extract data from the compiled earthquake catalogue of central, north and northwestern Europe (CENEC, Grünthal et al., 2009) with the following constraints: the complete catalogue for the region 43°-51°N and 5°E-13°E. This catalogue serves as a comparison opportunity, it is not used as an authoritative entry from a country as it is a compilation itself.

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Figure 2: Overview of catalogue data received from LED. Map of all events (top left), cumulative number versus time (top right, M ≥ 1.95 as black curve, all events in gray ), event magnitudes as function of time (bottom left, M ≥ 1.95 black, M < 1.95 gray) and (non)-cumulative frequency magnitude distribution (botttom right).


Prof. G. Grünthal agreed to deliver the extract, however GFZ is not allowed to deliver the SisFrance data which are used in CENEC (restriction by BRGM/EdF/IRSN). CENEC is prepared for Mw>=3.5 and covers Europe north of 44°N for the period from 1000AD to 2004. Uncertainties in the parameters are not provided in CENEC. Original parameters and their corresponding parameters in the ECOS database are listed in Table 5.

Figure 3 displays the seismicity map, the cumulative number of events as a function of time (top right), the event magnitudes (bottom left) as a function of time and the (non)-cumulative frequency magnitude distribution. For this display, we converted the origin time into decimal years. Earthquakes with no information on the following parameters were set to: month=1, day=1, hour=0, minute=0. These modifications are not entered in the data base.

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Table 5: ECOS database parameter, original parameters of the CENEC catalogue, description and range of data.


Date year Year 1996 2007Date month Month 1 12Date day Day 1 31Time h Hour 0 23Time min Minute 0 59Time SecondLat Lat Latitude [degree] 45.51 48.30Lon Lon Longitude [degree] 5.94 11.05Dep Dep Depth [km] 1 33

int intensityMagnitude mag Magnitude 0.2 5.5

Morig Original magnitudeMorig_type Original mag. type w LMw Derived Mw 3.5ref Reference to original catalog

Agency


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Figure 3: Overview of catalogue data received from GFZ. Map of all events (top left), cumulative number versus time (top right, M ≥ 3.5), event magnitudes as function of time (bottom left, M ≥ 3.5) and (non)-cumulative frequency magnitude distribution (botttom right).


1.3 France: Analysis of received catalogues

1. ISPN: French historical catalogue

We requested the historical earthquake catalogue of the Bureau de Recherche Geophysique et Minière (BRGM) and IRSN for an update of the regional earthquake catalogue with the following constraints::a) Large events with epicentral intensity >= 5 in the area 3°-9°E and 44°-51°Nb) All Events in the border area 5°-9°E and 45°-48.5°N J. Lambert sent a letter that the issue will be discussed together with IRSN, EDF and BRGM. We received an update, but no magnitudes where included, so we do not use this catalogue in building ECOS-09.

2. BCSF instrumental catalogue (BCSF09)

We requested the compiled regional earthquake catalogue from the Bureau Central Sismologique Francais (BCSF), the Réseau National de Surveillance Sismique (Renass) and the Laboratoire de Detection Géophysique (LDG). The request was for an extract of the compiled BCSF catalogue (RéNaSS + LDG catalogues) for the time period until the end of 2007 with all events in the area 3°E - 9°E and 44°N –51°N.

A first version was received via E-mail on Feb. 11 2009, covering the time period 2002-2007. Because the time period before 2002 was revised by BCSF after the compilation in ECOS02, a second request was sent. We obtained an update on March 3, 2009, original parameters and their range together with the corresponding ECOS database parameter are listed in Table 6. The catalogue and some important properties are displayed in Figure 4.Quarry blasts are not indicated in this catalogue.

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Table 6: ECOS database parameter, original parameters of the BCSF09 catalogue, description and range of data.


Date date Year 1964 2009Date date Month 1 12Date date Day 1 31Time date Hour 0 23Time date Minute 0 59Time date SecondLat Lat Latitude [degree] 45.51 48.30

dlat Uncertainty in Lat [degree] 0.00 1.61Lon Lon Longitude [degree] 5.94 11.05

dLon Uncertainty in Lon [degree] 0.00 1.35Dep Depth Depth [km] 1 33Magnitude mag Magnitude 0.2 5.5

localisation Location and arrondissmentAgency


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Figure 4: Overview of catalogue data received from BCSF. Map of all events (top left), cumulative number versus time (top right, M ≥ 1.95 as black curve, all events in gray ), event magnitudes as function of time (bottom left, M ≥ 1.95 black, M < 1.95 gray) and (non)-cumulative frequency magnitude distribution (botttom right).


1.4 Italy: Analysis of received / downloaded catalogues

1. INGV historical catalogue (CPTI04)

The regional earthquake catalogue was requested from from INGV Milano (Dr.M.Stucci). The request covered the newest version of the historical catalogue of Italy including all events with epicentral intensity Io ≥ 5 in the area 6°-13°E and 43°- 48°N.SED received a letter with the permission to use the Italian historical catalogue. The CPTI catalogue is available on a the website http://emidius.mi.ingv.it/CPTI . The official version is CPTI04. A new preliminary version CPTI08 is in progress, by Feb 2009 the time window 1900-2006 was available. We decided to wait for the an official catalogue release. The official catalogue CPTI04 was downloaded from the website in February 2009. The intensity databases DBMI are also available by internet http://emidius.mi.ingv.it/DBMI04/ .

Following the ECOS-09 review meeting and the advise of M. Stucchi, we defined entries of the catalogue CPTI04 as primary for earthquakes with magnitude M ≥ 4.5 since these were particularly reviewed for projects in probabilistic seismic hazard assessment for Italy.

2. INGV instrumental catalogue (CSI1.0, CSI1.1, CSI09, ISIDE, Bolletino)

The regional earthquake catalogue was requested from INGV Roma (Dr. F. Mele). We requested the instrumental catalogue until the end of 2007, including all events in the area 6°-13°E and 43°- 48°N. We received multiple files:

1. The integrated revision of the Italian seismicity (C.S.I. 1.1) covers the years 1981-2001 (Castello et al., 2006) and was downloaded from the website http://www.ingv.it/CSI/ on Feb.,10,2009.

2. A data file for the period 2002 of the CSI catalogue.3. January 1, 2003 – April 15, 2005: the old Bollettino Sismico INGV (INGV , 2006).4. April 16, 2005 – December 31, 2007: the new Bollettino Sismico Italiano, ISIDe

(Mele et al., 2007).

The format of the CSI1.1 is describe in Table 7, format information on the latter periods can be found at http://legacy.ingv.it/roma/reti/rms/bollettino/index.php.

The data for 2003-2007 were provided by Francesco Mele by email on January 20, 2009. A new version of the C.S.I. is under elaboration, but was not published officially as stated by Dr. Claudio Chiarabba, responsible of the Research Unit “Aggiornamento del catalogo sismico italiano (2003-2007): Catalogo della Sismicità Italiana CSI versione 2.0” of the DPC/INGV S1 project (2007-2009): “Determinazione del potenziale sismogenetico in Italia per il calcolo della pericolosità sismica”. Figure 5 displays the combined catalogues obtained from INGV. Earthquakes in the period 2003-2005 are mapped in red as the magnitudes of this period where only provided for ML ≥ 2.0 as can be seen in the magnitude of events versus time plot (Figure 5, bottom left). Magnitudes of this period are still under revision.

Quarry blasts are not indicated in the Italian catalogues. The CSI1.1 catalogue contains 45881 events with magnitude M=0.

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http://legacy.ingv.it/roma/reti/rms/bollettino/index.php

http://www.ingv.it/CSI/


http://emidius.mi.ingv.it/DBMI04/

http://emidius.mi.ingv.it/CPTI


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Table 7: ECOS database parameter, original parameters of the different files obtained, description and range of data. FileNr. refers to the list above.

ECOS Parameter Description Range FileNr.Min Max

Date Origin time Year 1964 2009Date Origin time Month 1 12Date Origin time Day 1 31Time Origin time Hour 0 23Time Origin time Minute 0 59Time Origin time Second

OT-error Origin time error 3Lat Lat Latitude [degree] 45.51 48.30Lon Lat Longitude [degree] 5.94 11.05

ceN,ceE Erz (km) Vertical location error (km) 1

ceN,ceE Horiz-Err Horizontal error [km] 2

ceN,ceE Latitude error Vertical location error (km) 4

ceN,ceE Longitude error Horizontal error [km] 4Dep Depth Depth [km] 1 33

ch Erh Horizontal location error (km) 1ch Vert-Error Depth error [km] 2ch Depth error Depth error [km] 4

Magnitude Preferred magnitude Magnitude 0.2 5.5

Magnitude type * Magnitude type 3Preferred magnitude error 4Preferred magnitude type 4Source 4Md 3,4Md Error 4ML 3,4ML Error 4RMS RMS (s) 1,2,3GAP Gap (deg) 1,2,3

Dist (km) Distance to nearest station (km) 1,2,3

Nph Number of phases 1,2,3

Catalogue code Event ID 1,2,3Network Name of sub network 3


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Figure 5: Overview of catalogue data received from INGV. Map of all events (top left), cumulative number versus time (top right, M ≥ 1.95 as black curve, all events in gray ), event magnitudes as function of time (bottom left, M ≥ 1.95 black, M < 1.95 gray) and (non)-cumulative frequency magnitude distribution (botttom right).


1.5 Austria: Analysis of received catalogue

ZAMG catalogue

The update of the regional earthquake catalogue was requested from the Zentralanstalt für Meterologie und Geophysik (ZAMG, W. Lenhardt). We requested

1. the historical catalogue including all events of epicentral intensity Io ≥ 5, West of 13°E.

2. the instrumental catalogue including all events west of 13°E. until the end of 2007.

We received both catalogues via email on Feb. 9, 2009, covering the instrumental part from 1980 -2009 (Table 8). Figure 6 displays some key properties of the catalogue. Quarry blasts are indicated in the catalogue.

Magnitude conversion:

For the period prior to 1975: Mw = M(ZAMG)From 01.01.1975: ML(SED) = M(ZAMG)

The first period reflects data that was delivered for ECOS-02.

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Table 8: ECOS database parameter, original parameters of the ZAMG catalogue, description and range of data. M* in the original catalogue refers to a macroseismic magnitude, a # indicates a quarry blast.


Date Year 1980 2009Date Mo Month 1 12Date Day 1 31Time HH Hour 0 23Time MM Minute 0 59Time Second 0 59Lat Br. Latitude [degree] 45.51 48.30Lon Lg. Longitude [degree] 5.94 11.05

z Depth [km] 0 40

Magnitude M Magnitude 0 7

Io Magnitude type 1 10RMS (s)

Jahr

Tg

Sek

Dep

Epizentrum


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Figure 6: Overview of catalogue data received from ZAMG. Map of all events (top right), cumulative number versus time (top left, M ≥ 1.95 as black curve, all events in gray ), event magnitudes as function of time (bottom left, M ≥ 1.95 black, M < 1.95 gray) and (non)-cumulative frequency magnitude distribution (botttom right).


1.6 Switzerland: Analysis of the catalogue

1. IECOS – instrumental earthquake catalogue of Switzerland

Although instrumental records of earthquakes in Switzerland and surrounding regions exist since the beginning of the 20th century, a modern nationwide seismograph network was put into operation by the Swiss Seismological Service in the early 1970s. Therefore, in view of completeness and uniformity of the data, this instrumental earthquake catalogue covers the period 1975-2008 and includes 9912 events with magnitude ML ≥ 0.1 for the territory monitored with the Swiss Digital Seismic Network. Parameters are listed in Table 9.

This catalogue covers the region included in the Swiss national map at the scale of 1:500'000 (Figure 7): Swiss km-coordinates: 480-865 / 262-302Geographic coordinates: 5.9-10.9E / 45.7-47.9N

Unless noted otherwise, the information corresponds to the information on file at the Swiss Seismological Service and is based mainly on the locations calculated using data from stations in Switzerland. For more information on the station network and data analysis procedures, see the yearly earthquake activity reports such as Baer et al. (2007) and Deichmann et al. (2008) on the home page of the Swiss Seismological Service. Events for which more reliable locations are available in the literature (events outside Switzerland and events which were studied in more detail), locations have been corrected accordingly. All magnitude values are those calculated by the Swiss Seismological Service.

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Table 9: Parameters of the instrumental Swiss catalogue for the period 1975-2008.


Date Origin time Year 1975 2008Date Origin time Month 1 12Date Origin time Day 1 31Time Origin time Hour 0 23Time Origin time Minute 0 59Time Origin time Second

Lat Lat Latitude [degree] 45.51 48.30Lon Lat Longitude [degree] 5.94 11.05

x-coordinate (Swiss) [km]y-coordinate (Swiss) [km]

Dep Depth Depth [km] -5.00 47.00Magnitude Preferred magnitude Magnitude 0.2 5.5

RMS RMS (s) 0 0.99GAP Gap (deg) 30 356

Dist (km) Distance to nearest station (km) 0 212

Nobs Number of Observations 3 77


Figure 7 displays the data using the local magnitude ML. Highlighted are the ML ≥ 3.95 earthquakes with red stars. The cumulative number of event plot highlights the improvement of the seismic network with time, in particular starting in 2001.

Table 10 shows the conversion from the ranking in Deichmann et al. (2008) to the ECOS-09 uncertainty classes. Assigned are also how these parameters should be understood in terms of standard deviations. We emphasize that the location uncertainties are most likely not distributed following a Gaussian distribution, however there are no formal reasons to believe another distribution is better suited.

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Table 10: Conversion of location uncertainties from IECOS (Deichmann et al., 2008) to ECOS-09 classes. ceN / ceE describe horizontal unceratinty class, ch the vertical uncertainty class (see Appenidix M). The columns σ(ceN,ceE) and σ(cH) denote how the location uncertainty is understood in multiples of the standard deviation.

IECOS parameters ECOS09 parametersRating Criteria Uncertainty ceN, ceE σ(ceN,ceE) ch σ(cH)Q GAP DM H Z

[degree] [km] [km] [km]

A ≤ 180 ≤ 2 ≤ 3 1 1 1 1B ≤ 200 ≤ 25 ≤ 5 ≤ 10 1 1 2 1C ≤ 270 ≤ 60 ≤ 10 > 10 2 1 3 1D > 270 > 60 > 10 > 10 3 1 3 2

≤1.5xZ


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Figure 7: Overview of Swiss catalogue data for the period 1975-2008 . Map of all events (top right), cumulative number versus time (top left, ML ≥ 1.95 as black curve, all events in gray), event magnitudes as function of time (bottom left, ML ≥ 1.95 black, M < 1.95 gray) and (non)-cumulative frequency magnitude distribution (botttom right).


2. General strategy to merge parametric earthquake catalogues

The general strategy for merging the various catalogues follows closely principles applied in the process to prepare the catalogue version ECOS-02. Alterations of the strategy origin in the limited resources and time available to create the catalogue ECOS-09. Our premise was to automate the process merging the catalogues as much as possible which is not entirely feasible.

Task definition:

Identifying duplicate entries in different catalogues covering the same regions is the main challenge. Entries are defined as the parametric description of an earthquake in one single catalogue. The search for duplicate entries, parametric descriptions of the same earthquake in different catalogues, focuses mainly on differences in location and origin time. Differences in the magnitude domain, for which different magnitude types need to be considered, are less important in the search if used at all. An automated identification process faces the challenge of trade-offs: applying too large time and distance windows lead to define entries of different catalogues to describe the same earthquake which are not the same. Using windows that are too small implies not to find all duplicate entries. In addition to this general problem, it is not straightforward to apply time-dependent filters. Without a doubt, location and timing of earthquakes have improved over the last decades and event parameters become more and more similar in recent years, however, there are still many differences especially in the location and magnitude determination.

Having these considerations in mind, we defined the following milestones for the generation of ECOS-09:

1. Compare the catalogues received for ECOS02 and this project from the authoritative institutions of the different countries; decide on priority scheme for catalogues to be used based on the comparison.

2. Generate a combined catalogue for each country: a national catalogue.3. Combine catalogues from all countries and search for duplicate entries, select and tag

entries as primary and duplicate.1. A primary entry defines the best possible information on one earthquake.2. Keep all entries to one earthquake in the catalogue: duplicate entries are related to

the primary entry through a unique identifier (GroupID). All entries remain in the database so all magnitudes can be provided.

4. Perform manual and automated quality control checks to revise the automatic procedure the entries from the different catalogues.

5. Combine instrumental catalogue with revised historical catalogue.6. Perform quality checks on the combined catalogue

◦ visual and statistical checks of the catalogue entries7. Assign appropriate Appraisals according to Appendix H (Table 2)

◦

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2.1 Comparison of catalogue versions from authorized institutions

2.1.1 Preparing a national catalogue for Germany

ECOS-02 combined five earthquake catalogues for the German territory, including instrumental and macroseismic catalogues from BGR, LED, the Geophysical Institute of Karlsruhe, a catalogue that was used for GSHAP (SED, 2002) and the CENEC catalogue. We received the above described updates from authoritative agencies for the German territory providing data for the study region: the Bundesanstalt für Geologie und Rohstoffe (BGR) and the Landeserdbebendienst Baden-Württemberg (LED). The catalogues from these two agencies are compared against the earlier versions as described in SED (2002) and combined to one national catalogue

Prior to LED (1996), the Geophysical Institute at the University of Karlsruhe provided data for the south western territory of Germany. This data is described in detail in the report on ECOS02 (SED, 2002).

We obtained an update of the catalogue from BGR for the period 1998-2007, the existing catalogue in the ECOS-02 databases covered 1968-1997. Thus, no detailed check was performed except for a time check at the merging date 01.01.1998.

Catalogs from the Landeserdbebendienst Baden-Württemberg (LED)

Duplicate search criteria: Δt=0.1min, Δd=10km, ΔM=0.5

Comparing the catalogue LED09 with the catalogue LED01 obtained for ECOS02, we found that all events of LED01 were in the new catalogue LED09. Therefore, we will defined LED09 as the catalogue to use for ECOS-09. Catalog LED09 compared to the combined catalogue of BGR68-07

Duplicate search criteria: Δt=0.1min, Δd=10km, ΔM=0.5

The BGR68-07 catalogue is a collection of various catalogues related to the original work with the parameter ref in the original data file. In particular, the catalogue contains events from the LED. We compared the catalogues for duplicates. Entries from the LED09 have higher priority, in case an entry is found in the BGR68-07 catalogue, it is just listed as duplicate.

For building a combined catalogue of the authoritative German institutions, we defined that events with latitude lat < 48.2 events in the BGR catalogue obtain lowest priority when compared with other national catalogues.

As the BGR68-07 catalogue is a compilation, entries in the BGR-catalogue that can be related to an agency providing original data for ECOS-09 will be identified as duplicate. If an entry is not found in an original catalogue, but is covered in time and space with the data we obtained from the original data, the entry will not be used. We think that catalogue updates in the original ones may not have made it to the compilation.

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In case a BGR catalogue is primary, the magnitudes are converted on the basis of the relations found for the agency the entry originates from.

2.1.2 Preparing a national catalogue for France

We obtained a catalogue (BCSF09) from the Université de Strasbourg (C. Nicoli,http://www.franceseisme.fr/) to prepare the new version of ECOS. We compared this catalogue to the catalogues ISPN01 and LDG01 that were obtained for ECOS02.

Comparison between catalogues BCSF09 – LDG01

Duplicate search criteria: Δt=1min, Δd=50km, ΔM=1.0

Through trial and error process varying the search criteria in time, distance and magnitude, we used the largest values for the duplicate search compared to the other national catalogues. We found large differences in location and magnitude for events occuring at the same (or similar) time. The magnitudes of the BCSF09 catalogue are in general smaller compared to the LDG01 magnitude (Figure 8).

Following the ECOS-09 review meeting in Zurich (December 2009) and the advise from the various experts contacted (O. Scotti, R. Bossu), we decided to use the entries of the LDG01 catalogue as primary entry for events in the period up to 2001 (see SED, 2002). According to the experts, the compiled catalogue of BCSF09 includes non-tectonic entries such as quarry blasts that are not included in the LDG01 catalogue. The BCSF09 catalogue provides data spanning a larger magnitude range. We do not add in these small magnitude events for the above outlined reason. Since magnitude in the SED02 and SED09 catalogue did not change, we keep the magnitude conversion formula of ECOS-02 for converting ML(LDG01) to ML(SED09).

We use the BCSF09 catalogue as the primary entry for the French territory starting in 2000. As the entries are not flagged we do not have means to differentiate between tectonic and

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Figure 8: Magnitude comparison between M(LDG01) and M(BCSF09). Histogram (left) and magnitude-magnitude plot (right) show strong differences with M(BCSF09) generally being smaller than M(LDG01).


non-tectonic events. We assume that small magnitude events are partially quarry blasts or mining induced events, yet, we are not able to remove these.

Comparison between catalogues BCSF09 – ISPN01

The comparison between these events only comprised a number of events. The comparison was done manually and events were selected.

2.1.3 Preparing a national catalogue for Italy

The authoritative agency for Italy is the Istituto Nationale de Geofisica e Vulconologia (INGV). We obtained 5 catalogues that mainly span different time periods (INGV_CSI1.0, INGV_CSI1.1, INGV_CSI09, INGV_bolletino99, INGV_BSI_ISIDE09).

The catalogue INGV_CSI1.0 spans the time period 1975-2001, INGV_CSI1.1 spans the period 1981-2001. Since the latter catalogue contains an updated version of the fist catalogue, this catalogue has higher priority. Events before 1975 are included from the INGV_CSI1.0 catalogue.

Following the ECOS-09 review meeting and the advise of M. Stucchi, we defined entries of the catalogue CPTI04 as primary for earthquakes with magnitude M ≥ 4.5 since these were particularly reviewed for projects in probabilistic seismic hazard assessment for Italy.

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Table 11: Details summary of catalogues received for ECOS02 and ECOS-09. Magnitude considers all magnitudes that were delivered within on catalogue. INGV_CSI11web contains 45881 events with magnitude 0.

Catalog Start time End time Magnitude range Depth range [km] # Events

min max min max min max min max

ItalyINGV_CSI10 01/02/1975 03/22/2001 1.20 5.40 6.01 13.00 44.00 47.50 0.00 143.00 13718INGV_CSI11web 01/01/1981 12/31/2001 0.00 5.90 4.68 23.34 34.88 50.97 0.00 631.00 81471CSI_09 01/01/2002 12/31/2002 0.40 5.60 5.78 21.43 35.60 47.56 0.00 234.00 3023INGV-bolletino99 01/02/2003 04/15/2005 0.00 5.20 6.33 13.00 43.00 47.64 0.00 70.00 7508INGV_BSI_ISIDE_09 04/16/2005 12/31/2007 0.00 4.40 6.36 12.99 43.00 47.96 0.00 74.00 7948

FranceISPN01 18/10/1356 12/29/1984 3.80 6.20 3.00 8.93 44.14 48.95 no depths 58LDG01 01/21/1962 12/29/1999 1.80 5.70 3.02 9.00 44.00 49.95 0.00 34.00 3194BCSF09 12/15/1964 01/31/2009 0.00 5.80 3.00 9.00 44.00 51.00 0.00 20.00 16450

AustriaZAMG01 04/05/1201 07/01/2001 1.40 6.10 9.55 16.98 46.43 48.45 1.00 22.00 431ZAMG09 03/26/1980 03/03/2009 0.00 5.30 9.01 12.98 46.40 48.18 0.00 35.00 4239

GermanyBGR01 09/29/1968 07/04/2001 2.50 5.70 5.07 13.00 47.00 51.00 0.00 40.00 1344LED01 01/17/1994 12/31/1999 0.00 7.10 2.95 30.70 41.10 51.74 0.00 28.00 669BGR68-07 07/21/1968 12/30/2007 2.00 5.90 5.04 13.00 47.00 51.00 0.00 40.00 5095LED09 01/14/1996 12/09/2007 0.20 5.50 5.94 11.05 45.51 48.30 1.00 33.00 747LED from BGR68-07 03/12/1980 12/14/2007 2.00 5.40 5.66 12.61 47.08 50.24 0.00 27.00 714

SwitzerlandSED02 01/01/1975 31/12/2000 0.1 5.5 5.9 10.9 45.7 47.9 0 40 5634SED09 01/01/1975 31/12/2008 0.1 5.5 5.49 11.05 45.51 48.3 -5 47 9912

Longitude range [°E] Latitude range [°N]


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Table 12: Magnitude types provided in catalogues.

Catalog Magnitude types

ItalyINGV_CSI10_delivered01 Md , MLCSI_delivered09 Mb(ISC) , ML(MDN) , ML(REG)INGV_BSI_ISIDe_09 Md , MLINGV_CSI11web M(CSI) , Mb(ISC) , ML(MDN) , ML(REG) , Mw(HVD) , Mw(MDN) ingv_bolletino09 Md , Ml

FranceISPN01 MmLDG01 Md, MLBCSF09 ML

AustriaZAMG01 MLZAMG09 ML

GermanyBGR01 ML mixture LED01 MD , ML , mb Karlsruhe01 MLLED09 MLBGR68-07 ML mixture

SwitzerlandSED02 MLSED09 ML


3. Merging the national catalogues to ECOS-09

3.1 Assessment of duplicate entries in combined catalogue

3.1.1 Basic principles

In general, the entry of a national catalogue for an earthquake that occurred in the territory of the country has the highest priority, thus will be marked as primary in the database. Entries from other catalogues identified as the same event will be tagged as duplicate and related to the primary by a unique identifier. This ensures to keep all information related to one event in the database.

Difficulties during the combination of the national catalogues arise mainly for entries that are close to national borders. Location uncertainty due to network configurations and data availability require a specific comparison. Considering the location uncertainties of modern instrumental catalogues, we decided in accordance with the procedures of ECOS02 to investigate a buffer zone 20km width on each side of the national borders (Figure 9). To assess duplicate events in the border zone, the distance of the events to the national borders (multiple distances for each event) are computed and the distances are archived in the database.

Search criteria for duplicate events: Swiss catalogue – other national catalogues

Period Time difference Epicentral distance Magnitude difference

Bufferzone

1975-2008 |Δt| ≤ 0.25 min |Δd| ≤ 10km |ΔM| ≤ 1.0 20km

1975-2008 |Δt| ≤ 0.25 min |Δd| ≤ 20km |ΔM| ≤ 1.0

Catalog priority ranking:Based on the seismic network capabilities, the location accuracy for the Swiss territory and surroundings, we decided to follow the following priority ranking of catalogues:

1. Swiss National Catalog 2. German National Catalog3. Italian National Catalog4. French National Catalog5. Austrian National Catalog

Guidelines to define duplicates:

1. Duplicates outside buffer zones in one countryEntries for events from a national catalogue located on the national territory outside the border zone have highest priority.

2. Duplicates located in buffer zone, locations in same countryIn case two or more catalogues have an entry for one earthquake with location all in the same country, the national catalogue has priority. ◦ Exception 1: If an event is located in the buffer zone for both catalogues in the

Swiss -French buffer zone, no matter if located in the same country or not, the Swiss catalogue entry has priority.

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3. Duplicates located in buffer zone, locations not in same countryIn this case, we follow the priority ranking of the catalogues.

4. Duplicates located in a national catalogue with location on national territory outside the buffer zone, other catalogues providing locations in the buffer zone: The national catalogue has priority.

5. Cross location outside the buffer zone:In rare cases, a entry of national catalogue A is located in country B and vice versa. In this case we follow the catalogue ranking in general after checking the event entries.

6. Events not listed in national catalogue:In some cases, a national catalogue A did not provide an entry on an earthquake located on the national territory of A, but entries from catalogues B and C provide information. In this case, the information was set to not valid for entries more than 40km inside country A.

3.1.2 Special cases

The composite BGR68-07-catalogue:

The catalogue from the Bundesanstalt für Geologie und Rohstoffe (BGR, BGR68-07) is a composite catalogue, thus contains events from different national and international sources. For details and documentation, please visit http://www.bgr.bund.de . As we also obtained the earthquake catalogue of the Landeserdbebendienst Baden-Württemberg (LED), we decided to give priority to the local catalogue, thus entries that could be related to the LED in the BGR

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Figure 9: Display of buffer zone 20km to each side of the national borders.

http://www.bgr.bund.de/


catalogue were not used. The same procedure applies to events from SED, LDG, ZAMG and INGV. For events originating from these agencies that are not in the newest version of the catalogue obtained for ECOS-09, we keep the entry from the BGR catalogue.

Magnitude conversion rules:Magnitudes of entries in the BGR catalogue that are related to an agency we have a specific conversion formula (e.g. LED), we apply the conversion formula. For those we do not have a conversion, we set ML(SED) = M(BGR)+0.2. Then we additionally apply the magnitude conversion ML(SED) to Mw(SED).

Border region Switzerland – Austria (SED09-ZAMG09):

In the border region of Switzerland and Austria, we apply a different rule due to network coverage. For events located west of longitude Lon<= 10.5°E, the entry of the Swiss catalogue has highest priority. East of longitude Lon > 10.5°E, the ZAMG catalogue entry has highest priority.In case an event in SED09 is located east of Lon=10.5 and located west of 10.5 in the ZAMG09 catalogue, it is decided case by case.

Border region Switzerland – Italy (SED09-all instrumental catalogues from Italy):

In this border region, a different rule applies based on network configuration reasons. North of Latitude Lat ≥ 45.45°N, the Swiss catalogue entry (SED09) receives the highest priority, below Latitude Lat < 45.45°N, the Italian catalogue (CSI) has the highest priority. In case an event is located north of Lat=45.45 in an Italian catalogue and south of 45.45 in the SED09, the SED09 has higher priority through default priority selection.

Entries from Karlsruhe catalogue (see ECOS-02) documentation)Entries of the catalogue from GPI Karlsruhe that that do not provide a magnitude estimate and are primary because of the location rules are assigned the magnitude of the BCSF catalogue. This concerns events before 1996.

3.2 Detailed procedures merging

To combine the catalogues, two parameters are essential to define the status of an entry in the catalogue:

Group ID: A simple unique identification numberAppraisal: Status of entry: primary, duplicate and others (Appendix K, Table 2)

The GroupID is indicating which events from different catalogues describe the same earthquake with different parameters.

At the beginning, parameter Appraisal is set to not used for all entries. The appraisal is changed through an iterative process describe below. The entries set to primary are the events that are the ones listed in the final version of ECOS-09. Entries describing the same event as the primary are set to duplicate.

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Entries which remain with the tag not used fail to meet any selection criteria. This can be due to various reasons (see details in Table 13):

• the entry is geographically falls out of the requested region or area of interest.• the entry does not contain a magnitude, a value M=nan or M=0 . • information from a newer catalogue of the same agency is available.

Tagging was performed in the following steps:

1. A basic selection of events was done for the different countries with preferences for events of newest catalogue

2. All catalogues of a country were compared with each other, the duplicates marked and the events from “older” catalogues introduced if necessary.

3. The four EU countries consisting of the previous selected events are compared with each other and again the duplicates found are marked.

4. The entire catalogue, excluding the duplicates found in previous steps, is compared with the Swiss catalogue and duplicates are marked. The procedure iterates using first tight limits in searching for duplicates and then larger limits as indicated in the search criteria.

3.3. Assigning magnitudes

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Table 13: Preselected tags for the different catalogues. All in primary means these entries obtained primary as a default. All in coulmn not used is eaqual to none in column primary.

Catalog Name Primary Duplicate Not used

SED09 allSED02 all

BGR68-07 all, expect events below Lat 48.2° after 14.1.1996BGR01 allLED09 allLED01 all

BCSF09 allLDG01 before 15.12.1964 after 15.12.1964ISPN01 before 1962

CSI1.0 before 1981 all after 1981CSI1.1 allCSI_delivered09 allINGV_bolletino09 allINGV_BSI_ISIDe_09 all

ZAMG09 allZAMG01 all


Each entry in the catalogue retains its magnitude and the magnitude of the primary entry is in general converted to the unified moment magnitude. For most entries, magnitudes from all agencies are converted to the local magnitude of SED-09 (ML(SED)) via linear regression and then the regression ML(SED) to MW(SED) is applied.

In case an original MW according to 1) Bernardi et al. (2005), 2) Baer et al. (2007) and Clinton et al. (2006), or 3) Braunmiller et al. (2002) is available, one of these is used. The priority sequence defined for ECOS-09, which can overrule the magnitudes of catalogue preference outside Switzerland is:

1. Mw published in Bernardi et al. (2005)2. Mw derived by Clinton with quality A (≥ 60% variance reduction, Baer et al. (2007),

Clinton et al. (2006))3. Mw derived by Braunmiller et al. (2005)4. Mw derived from ML (Appendix K)

This implies that a computed Mw from the Swiss Seismological Service overrules all other computed or derived Mw determinations.

4. Defining location uncertainties:

The majority of the catalogues provided to the ECOS-09 team did not include information on location and/or magnitude uncertainty. In case estimates of uncertainty are provided, it is in general not straightforward to interpret the uncertainty. It is not obvious that the uncertainties describe 1σ or 2σ bounds, neither for location nor for magnitude uncertainty. Furthermore, the standard deviation describes an uncertainty related to a Gaussian distribution which is an additional assumption that is made.

For location errors, it is important to understand the original computation of the uncertainties and it is essential to know which program was used. As we do not have all this information and in order to provide a consistent location uncertainty assessment, we decided to use a scheme by Deichmann et al., (2008) based on the GAP and the distance to the closest station. This, however, could not be applied to all data sets since we did not receive data or were not specific enough when we requested the data. The uncertainties determined based on the scheme by Deichman et al. (2008) were converted to ECOS-09 quality classes Appendix L). Data sets for which we do not have the information will not be associated with any quality class (Deichmann et al., 2008; Table 1) and obtain class 0 in the ECOS-09 classification (unknown). For data obtained from INGV, we used the location uncertainty given in the catalogue and converted those to the ECOS-09 quality classes. Table Table 14 summarizes the conversion scheme and the uncertainty bounds of the quality classes.

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5 . Defining magnitude uncertainty

Magnitude uncertainties are provided estimating the uncertainties for the Swiss local magnitude (ML(SED)) and combining the uncertainty with the uncertainty of the magnitude conversion (Deichmann et al., Appendix K).

Mw from CPTI04:Moment magnitudes Mw that are directly taken from the CPTI04 catalogue provide unusually small errors in of ΔMw = 0.01. For those events in ECOS-09 for which these events are primary due to the location rules, we keep this uncertainty, yet we do not think these are correct.

6. Additions from the CENEC catalogue

For some specific events, entries from CENEC have been implemented into ECOS-09. In general, CENEC is an improved version of the former catalogue by Grünthal and Wahlström (J Seismol 7:507–531, 2003a) and covers earthquakes in central, northern and northwestern Europe with Mw ≥ 3.50. Data from over 30 regional catalogues, the ISC and NEIC bulletins for the NE Atlantic Ocean, and many special studies were analyzed. Non-tectonic, non-seismic and nonexistent as well as duplicate events were identified and removed according to the current stage of knowledge. CENEC hence also improves some older entries provided by Bundesamt für Geowissenschaften und Rohstoffe, and compiled by G. Leydecker in 1986.

As a result the following events have been changed in the historical part of ECOS-09 following the review meeting with respect to I0, Mw or their status (true events vs. fake events): 1080-12-1, 1088-5-11, 1366-5-24, 1504-8-23, 1517-4-4 (fake event), 1534-7-14, 1565-2-7, 1591 (fake event), 1619-1-19, 1655-3-19, 1655-3-30, 1655-4-3, 1655-4-11, 1670-4-12 (fake event), 1755-12-9 (fake event), 1755-12-27 (2 events), 1756-1-26, 1903-2-25.

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Table 14: Conversion of location uncertainties from IECOS (Deichmann et al., 2008) to ECOS09 classes. ceN / ceE describe horizontal uncertainty class, ch the vertical uncertainty class (see Appenidix M). The columns σ(ceN,ceE) and σ(cH) denote how the location uncertainty is understood in multiples of the standard deviation. Rating Criteria Uncertainty ceN, ceE σ(ceN,ceE) ch σ(cH)Q GAP DM H Z

[degree] [km] [km] [km]

A ≤ 180 ≤1.5xZ ≤ 2 ≤ 3 1 2 1 2B ≤ 200 ≤ 25 ≤ 5 ≤ 10 1 2 2 2C ≤ 270 ≤ 60 ≤ 10 > 10 2 2 3 2D > 270 > 60 > 10 > 10 3 2 3 2


7. Quality assurance procedures for ECOS-09

The combined catalogue was subject to mulitiple quality assurance procedures since automated merging procedures are imperfect as pointed out earlier.

Quality assurance procedures:1. Manual check for M ≥ 2.5: (D. Eberhard, J. Woessner)

We performed a visual check of data for earthquakes with magnitudes M ≥ 2.5, regardless of magnitude type, for circles 200km centred at the locations of the nuclear power plants. Similarly, we looked at the same events for the region up to 20km outside the Swiss border to redefine the Appraisal manually. A list of manually revised Appraisals is available.

2. Checks against the original contribution from SED09 : (N. Deichmann)Entries for M ≥ 2.0 are checked for consistency with the contributed data.

3. Removing explosions and quarry blasts:We made specific searches for quarry blasts on the Swiss territory. These events are identified at the Swiss Seismological Service in a separate list. To avoid that quarry blasts are reentered in ECOS-09, we applied a duplicate search of the SED quarry blast file with ECOS-09 to remove possible reintroduced entries.

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References

Baer M., N. Deichmann, J. Braunmiller, J. Clinton, D. Fäh, D. Giardini, P. Kästli, U. Kradolfer and S. Wiemer (2007), Earthquakes in Switzerland and surrounding regions during 2006, Swiss J. Geosci., 100, 517–528, doi:10.1007/s00015-007-12422-0.

Bernardi, F., Braunmiller J. & Giardini D. (2005). Seismic Moment from Regional Surface-Wave Amplitudes: Applications to Digital and Analog Seismograms, Bull. Seism. Soc. Am., 95, pp. 408–418.

Braunmiller, J., N. Deichmann, D. Giardini, S. Wiemer and the SED magnitude Working Group (2002), Homogeneous Moment-Magnitude Calibration in Switzerland, Bull. Seismol. Soc. Am., February, v. 95; no. 1; p. 58-74; DOI: 10.1785/0120030245.

Castello B., Selvaggi, G., Chiarabba, C., and Amato A. (2006), CSI Catalogo della Sismicità Italiana, Versione 1.1, Istituto Nazionale di Geofisica e Vulcanologia, Centro Nazionale Terremoti. Available at: http://www.ingv.it/CSI/.

Chiarabba, C., Jovane, L., and Di Stefano, R., (2005), A new view of Italian seismicity using 20 years of instrumental recordings, Tectonophysics, 395, doi:10.1016/j.tecto.2004.09.013.

Clinton, J., Hauksson E., and Solanki K. (2006), An Evaluation of the SCSN Moment Tnesor Solutions: Robustness of the MW Magnitude Scale, Style of Faulting , and Automation of the Methid, Bull. Seismol. Soc. Am., 96, 1689-1705.

Deichmann N., M. Baer, J. Clinton, D. Fäh, D. Giardini, P. Kästli, U. Kradolfer and S. Wiemer (2008), Earthquakes in Switzerland and surrounding regions during 2007, Swiss J. Geosci., 101, 659-667,1661-8726/08/030659-9, doiI 10.1007/s00015-008-1304-y

Fäh, D., et al (2003): Earthquake Catalogue Of Switzerland (ECOS) and the related macroseismic database. Eclogae geol. Helv. 96, 219-236.

Grünthal, G. Wahlström, R, Stromeyer, D. (2009) The unified catalogue of earthquakes in central, northern, and northwestern Europe (CENEC) - updated and expanded to the last millennium, J. Seismology,doi:10.1007/s10950-008-9144-9.

Istituto Nazionale di Geofisica e Vulcanologia, 2006. Bollettino della sismicità strumentale 1983-2005. Centro Nazionale Terremoti. Available at: ftp://ftp.ingv.it/pro/bollet/

Mele, F.M., Marcocci, C., and Moro, R. (2007), ISIDe, Italian Seismic Instrumental and Parametric Database. Available at: http://ISIDe.rm.ingv.it/ .

Moro R., Basili A., Bono A., Marcocci C., Mazza, S., and Mele, F.M. (2008), ISIDe, an Italian Seismic Data Base with minimum magnitude of completeness ML 1.8. 31st General Assembly ESC 2008.

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Wiemer, S. and Baer (2000), M., Mapping and removing quarry blast events from seismicity catalogues, Bull. Seismol. Soc. Am., 90, 525-530.

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ftp://ftp.ingv.it/pro/bollet/


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