Neotectonics of the Caucasus and Kura valley, Azerbaijan

Abstract

Analysis of remote sensing, gravity, earthquake, horizontal and vertical motion data in the broader Azerbaijan region, located between the colliding Arabia and Eurasian Platform, indicates the overall dextral transpression. The region undergoes deformation by NW-SE striking transpressional strike-slip faults, pure strike-slip faults and thrusts. It is also deformed by N-S to NE-SW striking sinistral strike-slip faults. The study area is located to the NE of the main indentation point. The direction of indentation is roughly parallel to the NW-SE trending symmetry axis of the fanning horizontal motion vectors, to the NNW-SSE trending axis of the fanning 1-stress trajectories and to the fastest slowdown direction of horizontal motions in front of the advancing Arabia, which are all roughly parallel to the Arabian motion vector. The broader Azerbaijan region is situated in the eastern side of these fan-shaped patterns. It is characterized by 1 trends progressively changing from NNW-SSE to NE-SW and by the seismoactive zone thickness increasing SE-ward underneath the Kura Valley from 40 to almost 70 km. Its eastern portion, typical by its small-block mosaic structure, contains some unusual local stress regimes. It is argued that they are related to the addition of the regional tectonic stress, highly perturbed along numerous local strike-slip faults, to local stresses generated by interactions of local rotating blocks. This eastern portion is most prone to block rotations, being most distant from the main indentation point and being affected by the least transpressive strike-slip faulting.