Improvement and Harmonization of BSHAP Earthquake Catalogue

[Compilation of data, comparison with SHARE-GEM catalog]

Ines IvančićCroatian Seismological Survey, Department of

Geophysics, Faculty of Science, University of Zagreb, Zagreb

NATO SfP 984374 | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries

Unified BSHAP Earthquake CatalogueSummary on previous project - NATO SfP

983054

The BSHAP-1 catalog is compiled from:

- National catalogues:

Albania, Bosnia and Herzegovina, Bulgaria, Croatia, Greece, Hungary, Italy, Montenegro, Macedonia,Romania, Serbia and Slovenia

- Regional and Global catalogues:

Karnik 1996; Shebalin & Leydecker; ISC; NEIC; CMT Harvard Catalog; RCMT, INGV, Roma; RCMT, ETHZ, Zurich and EMMA database, Version 2

The initial BSHAP-1 catalogue

38.0 – 47.5 N12.5 – 24.5 E

M ≥ 3.513342 earthquakes

Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries, 2nd Workshop, Belgrade, 24-25 April 2013

Step

Task By Date

1 BSHAP-1 catalogue should be updated by reflecting any change after 2010 (the only update is required by Croatia in this meeting)

Croatia 15 May 2013

2 Finalized BSHAP-1 catalogue should be compared to the ISC-GEM catalogue for large events for any discrepancies

Albania 1 July 2013

3 Updates to the BSHAP-1 catalogue for 3.0≤M<3.5 earthquakes and any earthquakes occurred between 2010-2012 should be put together using 15 km buffer zones around national borders

Croatia 15 August, 2013

4 Neighbors should check the buffer zones and send updates to Croatia

All 1 September,

2013

5 After the catalogue is finalized, declustering and completeness check should be performed

Serbia 1 November,

2013

6 Method of updating the catalog in the future should be proposed

Macedonia

1 September,

2013

Plan for the WP1:

CROATIA

MONTENEGRO

SERBIA

ALBANIA

MACEDONIA

• Albania: 1964-2011, M ≥ 1.0• Croatia: 373BC-2012, M ≥ 3.0• Macedonia:

–479-2005, M ≥ 3.0 catalogue already submitted to BSHAP-1

–2006-2013, M ≥ 3.0 taken from the official Greek Catalogue (Aristotle University of Thessaloniki,http://geophysics.geo.auth.gr/ss/station_index_en.html)

• Montenegro: 1970-2012, M ≥ 3.0

• Serbia: 1970-2012, M ≥ 3.0• Bosnia and Herzegovina: ???

CATALOGUES SUBMITED FOR BSHAP-2

?

According to the agreement: • Update the BSHAP-1

catalogue for 3.0≤M<3.5 earthquakes after 1970

• Merge earthquakes occurred between 2010-2012

• … using 15 km buffer zones around national borders

Bosnia and Herzegovina: • missing catalogue

CATALOGUES SUBMITED FOR BSHAP-2

M≥3.0‘Clipped’ national earthquake catalogues

?

1970 - 2012

BSHAP-1M ≥ 3.5

Bosnia and Herzegovina

BSHAP-1 CATALOGUE (M≥3.5):• B&H participated with its national

catalogue

BSHAP-2 • missing national catalogue for events

3.0≤M< 3.5 after 1970 and events after 2010

• Red dots: BSHAP-1• Blue dots: CEC2012 (Croatian earthquake catalog)

1386 -2010M ≥ 3.5

BSHAP-1 and CEC2012 compared for events M≥3.5, in the period 1386-2010: BSHAP-1: 504 earthquakes CEC2012: 614 earthquakes

• All avaliable data from Croatian,

Montenegrin and Serbian catalogues were compiled for BSHAP-2 earthquake catalogue on the teritory of B&H

1386 -2012 M ≥ 3.0

BSHAP-2

FINAL SELECTION FROM THE CATALOGUES SUBMITED FOR BSHAP-1 UPDATE

MERGING BSHAP-2 CATALOGUE

PROCEDURE:

• Defining duplicate events in border region (15km)

• Removing events M < 2.4 & M ˃ 4.0 (1970 – 2012)from national catalogues

• Comparing it with BSHAP-1

PROBLEMS:• National catalogues

contain original data for all duplicate events resolved in BSHAP-1

• Because of the possibility to create new duplicates, it was of great importance to determine events previosly resolved in BSHAP-1

CRO

B&H

ALB

MN

MN

• Earthquakes within border region: approx. 15 km from the both sides of the border

• Finding duplicate events between neighbouring countries: Croatia – Monte Negro, Monte Negro – Serbia, Monte Negro – Albania and Serbia - Albania

• Comparing duplicates with BSHAP-1 catalogue: all events resolved in BSHAP-1 catalogue were identified.

• Assigning corresponding country to the event. It was done with the use of MapInfo program and the geographical coordinates in its Europe.tab file. (Possible discrepancies with real border coordinates?)

DEFINING DUPLICATE EVENTS IN BORDER REGION

• T ± 90 s or less?• D ± 40 km or less?• Every doubtful event

should be manually checked?

BSHAP-2 Earthquake Catalogue

38.0 – 47.5 N12.5 – 24.5 E

510BC – 1969M ≥ 3.5

1970 – 2012M ≥ 3.0

19539 earthquakes

BSHAP-2 Earthquake Catalogue – estimating completeness

39.2 – 46.6 N12.8 – 23.3 ETime distribution of seismic

events (mainshocks) by year (1970-2012) , (ML ≥ 3.0)

Magnitude frequency distribution of earthquakes

MC ≥ 4.0 (bML = –1.12)

(max.-likelihood b-value, after Gutenberg-Richter relationship)

Maximum magnitude by year:

Magnitude timeline1970-2012, M ≥ 3.0 (Mw|ML or MLH)

(19539 earthquakes)

BSHAP-2 Earthquake Catalogue

Num

ber

of e

q. p

er y

ear

Mag

nitu

de

Count

Gap in magnitude distribution at aprox.

3.5 <M<4.0 due to irregular spatial

distribution of earthquakes with

magnitude M<4.0!

Blue dots: BSHAP-2Red dots: BSHAP-1

Magnitude distribution of mainshocks in narrower area of BSHAP-2 catalogue (9698 eq):

Magnitude distribution of mainshocks in narrower area of BSHAP-2 catalogue (9698 eq):

Magnitude distribution of all earthquakes in narrower area of BSHAP-2 catalogue (9007 eq):

BSHAP-2 catalogue compared to the ISC-GEM catalogue for large events for any discrepancies

38.0 – 47.5 N12.5 – 24.5 E

M ≥ 5.5

http://www.isc.ac.uk/iscgem/index.php

ISC-GEM Global Instrumental Earthquake Catalogue(1900-2009), M ≥ 5.5

ISC-GEM catalogue

Determinig same events:

Green dots: ISC-GEMRed dots: BSHAP-2

ISC

-GE

MB

SH

AP

-2

Comparing BSHAP-2 and ISC-GEM

38.0 – 47.5 N12.5 – 24.5 E

M ≥ 5.5

http://www.isc.ac.uk/iscgem/index.php

ISC-GEM Global Instrumental Earthquake Catalogue(1900-2009), M ≥ 5.5

Green dots: ISC-GEMRed dots: BSHAP-2

SHARE European Earthquake Catalogue (SHEECv3.3) 373BC – 2006

http://www.efehr.org:8080/jetspeed/portal/hazard.psml

Grünthal, G., Wahlström, R., Stromeyer, D. (2013), The SHARE European Earthquake Catalogue (SHEEC) for the time period 1900-2006 and its comparison to EMEC. Journal of Seismology

BSHAP-2 catalogue compared to the SHEEC catalogue (SHARE European Earthquake Catalogue (ver. 3.3))

38.0 – 47.5 N12.5 – 24.5 E

BSHAP-2 comparison with SHARE (SHEEC) catalog

Yellow dots: SHARE-GEMRed dots: BSHAP-2

SHEEC38.0 – 47.5 N12.5 – 24.5 E373BC – 2006

M ≥ 3.06609 earthquakes

BSHAPE-238.0 – 47.5 N12.5 – 24.5 E510BC – 2006

M ≥ 3.017614 earthquakes

Time difference

Distance difference

SH

EE

CB

SH

AP

E-2

MN

Mwu(BSHAPE-2)

BSHAP-2 comparison with SHARE-GEM (SHEEC) catalog

BSHAP-1 – SHEEC compared magnitude distribution Determining same

events:

Magnitude-difference distribution (Mwu-Mw)/Mwu(BSHAP)

Mwu(BSHAPE)/Mw(SHARE) magnitude regression

4052 earthquakes

-0.5≤M≤0.5 87% eq.

CONCLUSION

Accomplished tasks:• Updated BSHAP-2 catalogue with 3.0≤M<3.5

earthquakes and earthquakes occurred between 2010-2012 according to updated national earthquake catalogues

• Determined duplicate events in 15 km buffer zones around national borders

• Updated Bosnia and Herzegovina earthquake catalog with all available data from Croatian, Montenegro and Serbian national catalogues

Tasks to be accomplished:• Neighbors should check buffer zone updates • Declustering and completeness check should be

performed

Proposed tasks:• Updating BSHAP-2 catalogue with 3.0≤M<3.5 events and

events occurred between 2010-2012 from neighboring countries (Italy, Slovenia, Hungary, Romania, Bulgaria and Greece) if possible

• Unification of the magnitudes, especially according to new updates

• Examining and filtering the BSHAP Earthquake Catalogue for missing or duplicate events

And finaly providing a final earthquake catalogue compatible with international standards

CONCLUSION