The Geodynamics before and after the February 6, 2023 Earthquake Doublet in Turkey According to Satellite Radar Interferometry Data

Using the Stacking-InSAR satellite radar interferometry method, the time series of the velocity fields of vertical and horizontal displacements of the geoblocks in the west-east direction before and after the doublet earthquakes with magnitudes of 7.5 and 7.8 that occurred in Turkey on February 6, 2023 are calculated. Segmentation into blocks with similar displacement velocities is performed using the cluster analysis of the displacement velocity fields. It is established that the boundaries of the blocks with the different temporal geodynamics correspond to bends and transitions from one segment of the East Anatolian Fault zone (EAF) to another. In the EAF area bending in the south-east direction, an extensive small-block structure with the different displacement velocities before the earthquakes is detected, the zone of which is found to locate both epicenters of 7.8 and 7.5 earthquakes. The analysis of the temporal dynamics of the displacement velocity fields from 2016 to February 2023 confirmed that one of the significant early triggers of the earthquake doublet was an anomalous shift (for about 20 cm) of the small geoblock in the west direction, which was associated with seismic activity on January 24, 2020. The data on the geodynamics of the region showed the continuous occurrence of the significant displacements during the first eight months after the earthquake doublet and the subsequent formation of the stationary processes of shift for this region.