MODERN SEISMOGEODYNAMICS OF TURKEY, NORTHERN IRAN AND CAUCASUS REGION

Abstract

Large transverse fault zones divide the Alpine-Himalayan belt into several segments. The entire Arabian-Iranian segment and parts of two neighboring segments fall within the region under consideration: the Adria-Aegean and the Pamir-Himalayan. The structure of the segments has similar features. In 2023, an increase in seismic activity was observed on the territory of the Anatolian plate, the Iranian block and the Caucasus region: 04/18/2021 southern İran M=5.8; 01/11/2022 Cyprus region M=6.6; 10/05/2022 north western İran M=5.6; 11/23/2022 western Turkey M=6.7; 02/06/2023 central Turkey M=7.9, 7.4; 07/03/2023 Caspian Sea, offshore azerbaijan M=5.6; 12/07/2023 Caspian Sea, offshore Azerbaijan M=5.6. This article analyzes seismic activity for the period 2020-2023, mechanisms of earthquake foci, tectonics, as well as data obtained at GPS stations. The features of the geodynamic regime of each region under study, the types of tectonic movements, fault tectonics and the values of the velocities of horizontal movements of tectonic blocks  have been established. Analysis of the velocity field of GPS stations showed the heterogeneity of deformation processes in the region of the Eastern Mediterranean and the Caucasus. The considered results show the movement of the Arabian plate relative to the Eurasian plate. Considering the speed of movement of the Anatolian and Eurasian plates, and the Arabian and Anatolian plates, it was established that for the East Anatolian - 14 mm/year. This indicates the convergence of the Anatolian and Eurasian plates through a system of dextral strike-slip faults in eastern Turkey and a thrust system in the Caucasus. The total reduction in distance between the Lesser and Greater Caucasus is 10 mm/year. A study of the North Anatolian essentially right-lateral strike-slip active zone showed that seismogenic movements during modern and historical
earthquakes, as a rule, retain the predominance of right-slip displacements, but at the same time have a larger vertical component than the total Quaternary displacement in this zone. For the region of the Arabian Caucasian junction, a recalculation of movement vectors relative to the fixed northern part of the Arabian Plate was performed. It showed small movements of points of the adjacent part of the Anatolian plate to the southwest, and the speeds of movement, not exceeding 4-8 mm/year immediately near the East Anatolian fault zone, increase to the northwest to 8-12 mm/year, while points located south of the East Anatolian zone and west of its junction with the Levantine zone, they moved in southern directions at speeds of 4-5 mm/year.