The relation of seismic velocity and attenuation pattern in the East Anatolian fault zone with earthquake occurrence: Example of January 24, 2020 Sivrice earthquake

Abstract

The East Anatolian Fault Zone (EAFZ) is one the main tectonic elements of Turkey, which borders the Anatolian plate from the east. EAFZ, which is NE-SW direction, consists of many fault segments. In the historical and instrumental period, many damaging earthquakes occurred, the largest being 6.8 (Ms) as the 1971 Bingöl earthquake. The last magnitude 6.6 (Ml) (Mw = 6.8) earthquake occurred on January 24, 2020 in Elazig - Sivrice Hazar - Sincik segment of EAFZ. However, considering the historical and instrumental activity, it is seen that many fault segments are silent. In this study, the silent and active segments, and their seismic velocity (as % Vp and Vp) and attenuation pattern (as Q-1 p) are determined in order to determine the earthquake behavior of EAFZ in the near future. From the results obtained by using the data of the earthquakes that occurred from 2007 to the end of 2019, it was clearly determined that the velocity and attenuation increased on the Hazar - Sincik segment. It has been determined that Vp is 4.08-8.2 km/sec, Q-1 p is ± 0.005 and the frequency dependency varies between 0 - 1.08 along the zone. The variation of velocity and attenuation on the segments where the earthquake occurred and in the silent section were revealed.