Deep structure and geodynamic peculiarities of the earth crust of the western coast of the Caspian sea

Abstract

The article presents 2D gravity model of the geodynamic profile of Samur—Baku, located on the western coast of the Caspian Sea and the geodynamic characteristics of the earth crust in the profile region are studied. 2D gravity model is made by the matching method of density boundaries. The boundaries of the lower layer of crust (28—32 km) and the Moho surface (47—57 km) are specified. Along the profile, the velocity curves of modern vertical and horizontal motions are analyzed. On the curve of velocities of modern vertical motions on the boundary of the rise and fall of the earth’s crust, places of stress accumulation zones along the profile were identified. Modern vertical motions of the earth’s crust show that along the profile the main stress accumulation zones are located in the immediate vicinity of the points Khudat, Charkhi, Siazan and Baku. The average deformation velocity between two GPS points was calculated by dividing the velocities difference to the distance between these points. It is established that the zone of the highest deformation velocity (97,5 nanostrain/year) coincides with the zone of the Siazan fault, the zone of the Gusar-Shabran edge trough is characterized by a velocity of 22,3 nanostrain/year. The low deformation velocity (8,9 nanostrain/year) coincides with the zone of the Shamakhi-Gobustan synclinorium. These zones of stress accumulation in the gravity model coincide with the protrusions along the surface of the upper and lower layers of the consolidated crust and marked by hypocenters of earthquakes. The values of the radii of foci of earthquakes that create additional perceptible stresses that affect the geodynamic conditions of the earth crust in the profile region are determined.