DETERMINATION OF THE DEPTHS OF THE ACTIVE BLOCKS ACCORDING TO THE DATA OF THE GPS STATIONS

Abstract

Based on the correlation of GPS data and hypocenters of strong earthquakes, the boundaries were identified and the depths of occurrence of active tectonic blocks in the areas of the southeastern subsidence of the Greater Caucasus, the Kura depression and the Talysh zone of Azerbaijan were determined. It has been established that the velocity field of GPS observations on the territory of Azerbaijan clearly illustrates the predominance of the movement of the earth's crust in the N-NE direction relative to Eurasia. The most clearly manifested feature of the velocity field is a decrease in  velocity at observation points located on the territory of the Greater Caucasus. GPS observation points located along the MCT show a decrease in speed in an easterly direction. N-NE movement of the earth's surface is interpreted as one of the reasons for the accumulation of stresses on this thrust. In addition, there is a tendency for horizontal movement within the Kura depression and the Lesser Caucasus, where the speed increases from west to east along the strike of the mountain range. In addition, the analysis of the azimuth angles showed an increase at the stations located on the Absheron Peninsula. Based on the correlation of GPS data and hypocenters of strong earthquakes, in the GubaGusar region in the direction NW-SE at a depth of 5 to 40 km, a block with velocities of 5.8 mm/g and a length of 55 km is distinguished. On the depth profile of Zakatala-Gobustan (NW-SE) in the southeast direction at an epicentral distance of 20 to 250 km, a gradual subsidence of the tectonic block is observed with velocities of 6.25 mm/g from a depth of 20 to 55 km. In the zone of the West Caspian fault at depths from 5 to 35 km, a block boundary is distinguished with velocities of 7.25  mm/y. On the eastern side of this block, a block is distinguished at depths of 10–25 km with values of 9 mm/y