High Seismicity Intersections of Morphostructural Lineaments: The Black-Sea–Caspian Region

Abstract

The highly seismic Black-Sea–Caspian region contains conjugate mountain edifices of the Caucasus, Alborz, and Kopet Dagh, the Rioni and Kura intermontane troughs, and the deep southern Caspian basin. The goal of the present study is to determine potential sites of larger (М ≥ 7.0) earthquakes in the region. This was done using the methodology designed for identification of sites of possible large earthquakes. The earthquake-generating features are considered to be intersections of morphostructural lineaments as identified by morphostructural zoning. The epicenters of М ≥ 7.0 earthquakes correlate with lineament intersections. The Kora-3 pattern recognition algorithm was used to separate all intersections in the region into high- and low-seismicity ones with respect to М ≥ 7.0 based on the geological and geomorphologic parameters that characterize vicinities of intersections. The result was to recognize 150 intersections as having potential for М ≥ 7.0 earthquakes of a total of 510 intersections that were found in the region by morphostructural zoning. All of these intersections are within mountain belts. No intersections that can generate М ≥ 7.0 earthquakes have been identified in the intermontane troughs and within the southern Caspian deep-sea basin, whose crust is thinner. According to the geological and geomorphologic features of high seismicity intersections, as identified here, they are characterized by high contrasts in neotectonic movements and increased crustal fragmentation.