Preliminary Seismo-Tectonic Analysis of the Catastrophic Earthquake in South-Eastern Turkey on Feb 6, 2023

Abstract

—In this paper, we carried out a kinematic analysis of the movements of plates and blocks of the region based on a homogeneous database of displacement velocities of GNSS permanent monitoring stations for the region of southeastern Turkey, where strong earthquakes occurred on February 6, 2023. Along the East Anatolian fault zone from 2008 to 2018, the Arabian Plate was established to shift relative to the Anatolian Plate, corresponding to a left shift (without a normal component) at a rate of 1 cm/yr in the eastern part to 0.8 cm/yr in the western part. Displacements occurred along the Chardak fault, corresponding to a left-hand strike-slip fault, at a rate of less than 0.7 cm/year. The revealed kinematics is confirmed by focal mechanisms and cosesismic displacements of the studied earthquakes. The M7.5 earthquake that occurred directly on the Chardak fault is not an aftershock of the M7.8 earthquake, but is a relatively independent event. An analysis of the seismic regime shows that the stresses on the East Anatolian fault after the main event M7.8 are relieved by the first large latitudinal fault zone (the Chardak fault). The results of our study suggest that the counterclockwise rotation of the Anatolian and Arabian plates associated with the opening of the Red Sea Rift is most likely decisive for the general kinematics of the plates in the region.