According to new geophysical investigations this article focuses on 2D gravitational model of the Earth Crust deep structure and the upper mantle along regional profile Elburs-Absheron threshold crossing South Caspian depression. The model has been analyzed on the base of focal mechanisms of earthquakes focuses. It has been done by selection method of density borders of oceanic crust upper border and Moho discontinuity. Integrated study of gravitation and seismicity data along profile provides a new information of subduction zone in north of SCD. Thickness of Mesozoic layer in middle part of profile (~8 km) gradually increases northward and in area of the Absheron threshold it reaches its maximum value (~20 km). It is supposed that it resulted from collision between oceanic and continental crust. In their combining zone of the northern area represented in model one can see bend of oceanic crust probably is connected with starting lithosphere subduction process of South Caspian beneath the Middle Caspian. Subduction under the Absheron threshold is accompanied by detachment from basaltic layer of upper sediments.