Improvement and Harmonization of BSHAP Earthquake Catalogue [ Compilation of data, comparison with SHARE-GEM catalog ] Ines Ivančić Croatian Seismological Survey, Department of Geophysics, Faculty of Science, University of Zagreb, Zagreb NATO SfP | Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries

Unified BSHAP Earthquake Catalogue Summary on previous project - NATO SfP 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  N 12.5 – 24.5  E M ≥ earthquakes

Improvements in the Harmonized Seismic Hazard Maps for the Western Balkan Countries, 2 nd Workshop, Belgrade, April 2013 StepTaskByDate 1BSHAP-1 catalogue should be updated by reflecting any change after 2010 (the only update is required by Croatia in this meeting) Croatia15 May Finalized BSHAP-1 catalogue should be compared to the ISC-GEM catalogue for large events for any discrepancies Albania1 July Updates to the BSHAP-1 catalogue for 3.0≤M<3.5 earthquakes and any earthquakes occurred between should be put together using 15 km buffer zones around national borders Croatia15 August, Neighbors should check the buffer zones and send updates to Croatia All1 September, After the catalogue is finalized, declustering and completeness check should be performed Serbia1 November, Method of updating the catalog in the future should be proposed Macedonia1 September, 2013 Plan for the WP1:   

CROATIA MONTENEGRO SERBIA ALBANIA MACEDONIA Albania: , M ≥ 1.0 Croatia: 373BC-2012, M ≥ 3.0 Macedonia: – , M ≥ 3.0 catalogue already submitted to BSHAP-1 – , M ≥ 3.0 taken from the official Greek Catalogue (Aristotle University of Thessaloniki, Montenegro: , M ≥ 3.0 Serbia: , 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 … 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

BSHAP-1 M ≥ 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) M ≥ 3.5 BSHAP-1 and CEC2012 compared for events M≥3.5, in the period : 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 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 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  N 12.5 – 24.5  E 510BC – 1969 M ≥ – 2012 M ≥ earthquakes

BSHAP-2 Earthquake Catalogue – estimating completeness 39.2 – 46.6  N 12.8 – 23.3  E Time distribution of seismic events (mainshocks) by year ( ), (M L ≥ 3.0) Magnitude frequency distribution of earthquakes M C ≥ 4.0 (b ML = –1.12) (max.-likelihood b-value, after Gutenberg-Richter relationship) Maximum magnitude by year:

Magnitude timeline , M ≥ 3.0 (Mw|M L or M LH ) (19539 earthquakes) BSHAP-2 Earthquake Catalogue Number of eq. per year Magnitude 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-2 Red dots: BSHAP-1 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  N 12.5 – 24.5  E M ≥ ISC-GEM Global Instrumental Earthquake Catalogue ( ), M ≥ 5.5 ISC-GEM catalogue Determinig same events : Green dots: ISC-GEM Red dots: BSHAP-2 ISC-GEM BSHAP-2 Comparing BSHAP-2 and ISC-GEM

38.0 – 47.5  N 12.5 – 24.5  E M ≥ ISC-GEM Global Instrumental Earthquake Catalogue ( ), M ≥ 5.5 Green dots: ISC-GEM Red dots: BSHAP-2

SHARE European Earthquake Catalogue (SHEECv3.3) 373BC – Grünthal, G., Wahlström, R., Stromeyer, D. (2013), The SHARE European Earthquake Catalogue (SHEEC) for the time period 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  N 12.5 – 24.5  E BSHAP-2 comparison with SHARE (SHEEC) catalog Yellow dots: SHARE-GEM Red dots: BSHAP-2 SHEEC 38.0 – 47.5  N 12.5 – 24.5  E 373BC – 2006 M ≥ earthquakes BSHAPE – 47.5  N 12.5 – 24.5  E 510BC – 2006 M ≥ earthquakes

Time difference Distance difference SHEEC BSHAPE-2 MM N 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 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 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