Source Mechanism and Rupture Process of the 24 January 2020 Mw 6.7 Doganyol-Sivrice Earthquake obtained from Seismological Waveform Analysis and Space Geodetic Observations on the East Anatolian Fault Zone (Turkey)

Abstract

Here, we present the source mechanism and rupture process for the destructive 24 January 2020 Mw 6.7 Doganyol-Sivrice earthquake at the East Anatolian Fault Zone (EAFZ, Turkey), obtained from seismological waveform analysis and space geodetic observations. Multi-data analyses and modelling in the present study provide fundamental data and strong constraints for retrieving complex source mechanism of an earthquake and its spatiotemporal slip characteristics along the ruptured segment of fault. The acquired slip model of this earthquake reveals heterogeneous slip distribution along strike N244 degrees E of the fault plane dipping NW (68 degrees) with duration of the source time function (STF) and low stress drop value (Delta sigma) of similar to 25 s and similar to 6 bars, respectively. Back-projection analysis validates fault length (L) stretching along strike for a distance of similar to 75 km and supports predominant south-westerly bilateral rupture propagation with a variable rupture velocity (Vr) of similar to 2.3-3.4 km/s along with two main patches, presumably a sequence of two asperities being ruptured following the surface trace of the EAFZ. The distribution of aftershocks based on the analysis of two months long data consistently confirms spreading of seismicity along the ruptured fault. The evaluation of Interferometric Synthetic Aperture Radar (InSAR) data reveals that left-lateral co-seismic slip and significant deformation extends for similar to 20 km on either side of the fault with evident post-seismic displacement. Yet, no significant vertical offsets were observed as GNSS stations detected only horizontal motions. Coda-wave analysis as an independent tool also confirms moment magnitude of Mw 6.7. Our results highlight a case of a damaging earthquake and enhance our understanding of earthquake mechanics, continental deformation and augmented earthquake risk on the EAFZ.