EFFECT OF EARTHQUAKE CATALOGS DECLUSTERING ON THE SEISMIC HAZARD ASSESSMENT

N.A. Galina1, 2, V.V. Bykova1, R.N. Vakarchuk1, R.E. Tatevosian1

1Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia

2 Lomonosov Moscow State University, Moscow, Russia

Abstract. The effect of various preliminary processing methods of seismic catalogues on seismic hazard assessment is studied. The impact of declustering, i.e. the removal of dependent events, and the choice of the completeness magnitude was investigated. The catalogues of the Kamchatka and Caucasus regions were used for the analysis, because synthetic catalogues may not show the real features of regional seismicity. The declustering impact on seismic hazard calculations is illustrated by the examples of Kamchatka and Caucasus regions, where probe sites were selected. Three methods of declustering are considered: there is a different number of events in the catalogues after their application. The plotted hazard curves indicate a complex «interaction» of catalogue declustering with the choice of the completeness magnitude, since both of them affect the b-value, and it is not always possible to predict in advance whether this leads to an increase or a decrease in the estimate of b-value. The method of declustering, which leaves most events in the catalogue, does not always give the highest hazard estimate. In this regard, it is necessary to note again that it should be treated with special care and attention to declustering of catalogues. At least, it should be taken into account that this procedure can affect the final result unpredictably.

Keywords: seismic hazard, declustering, completeness magnitude, b-value.

About the authors:

GALINA Natalia Alexandrovna - student, Lomonosov Moscow State. 119234, Moscow, Leninskie gory, 1, building 2; Engineer, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1. Tel.: +7 (915) 059-11-49. E-mail: na.galina@physics.msu.ru

BYKOVA Vera Vyacheslavovna - Candidate of Physical and Mathematical Sciences, Leading Scientific Associate, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1Tel.: +7 (499) 254-53-16. E-mail: vvb@ifz.ru

VAKARCHUK Roman N. - Senior Researcher, Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1. Tel .: +7 (499) 254-30-42. E-mail: roman@ifz.ru

TATEVOSYAN Ruben Eduardovich - doctor of physical and mathematical sciences, chief scientific fellow. Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences. 123242, Moscow, ul. Bolshaya Gruzinskaya, 10, building 1. Tel.: +7 (499) 254-30-42. E-mail: ruben@ifz.ru

Cite this article as: Galina N.A., Bykova V.V., Vakarchuk R.N., Tatevosian R.E. Effect of earthquake catalogs declustering on the seismic hazard assessment, Voprosy Inzhenernoi Seismologii (Problems of Engineering Seismology), 2018, Vol. 45, No. 1, pp. 5–18. [in Russian]. DOI: 10.21455/VIS2018.1-1

English translation of the article will be published in Seismic Instruments, ISSN: 0747-9239 (Print) 1934-7871 (Online), https://link.springer.com/journal/11990), 2019, Volume 55, Issue 1.