Earthquake potential of the East Anatolian fault

This study aims to forecast magnitude of future strong (6.0≤ M <7.0) and major (7.0≤ M <8.0) earthquakes along the East Anatolian Fault Zone (EAFZ hereafter), which is a seismically active plate boundary between Arabian and Anatolian plates. In this context, we investigated segmentation of the EAFZ reviewing previous studies on structural variation zone and historical earthquakes. We analysed the combined GPS velocity field to obtain back-slips using steepest descent/gradient inversion method. The method projects GPS-derived back-slip rates onto the fault plane using Okada's quasi-infinite space model simulating elastic Green's functions to obtain on-fault slip deficit rates. Resulting slip deficit rates are used to estimate present-day slip budgets on each fault segment. We also analysed along-fault b-value distribution to verify if it can be used to differentiate between locked and creeping patches. Our results show that the EAFZ currently have a 1.51 m average slip. We suggest that the EAFZ is split into eight fault segments generating strong/major earthquakes. The January 24, 2020 Elazığ earthquake (M 6.8) ruptured the Sivrice-Pütürge segment verifying our segmentation model and magnitude forecasts for future earthquakes. We found no slip deficit accumulation observed on the Hacılar segment. Remaining six segments are able to generate three strong, three major earthquakes. Currently Karlıova, Kaleönü-Beyhan, Palu-Sivrice, Taştepe, Çelikhan-Erkenek, Gölbaşı-Pazarcık segments can currently generate M 7.0, M 6.9, M 7.1, M 6.8, M 6.9, M 7.4 earthquakes, respectively. Karlıova, Palu-Sivrice, Taştepe, Gölbaşı-Pazarcık segments currently have the potential to generate previous strong/major earthquakes they hosted. We observed a reverse correlation between slip deficit rates and b-values verifying that b-value can be used to discriminate locked and creeping fault segments.