The high-speed structure of the upper floors of the mantle of the Black Sea basin

Abstract

Lateral velocity variations in the mantle lithosphere of the Black Sea basin down to the depth of 80 km were estimated from travel time residuals of P-waves recorded at the coastal stations from earthquakes within and around the Black Sea. The observed data were corrected for the crust structure that allowed us to get more accurate information on the velocity distribution in the mantle lid. We applied the tomography method in which the 3D region under study was divided by cells and velocity correction in each cell was estimated. Some new features of the mantle lid structure have been found which reflect history of formation and evolution of the Black Sea depression. It has been shown that the Black Sea basin is not a single block: it consists of two different depressions distinguished by the velocity structure and orientation. They are separated by a low-velocity zone, western and eastern parts of which coincide with the West-Crimean fault and the Trans-Black Sea fault correspondingly.