Selective Manifestation of Sesmogenic Stress Field within the Mediterranean Belt (Based on Earthquake Focal Mechanism Solutions)

Separate domains of the Mediterranean belt (Zagros, Vrancea, and the Crimea-Caucasus-Black-Sea region) are discussed to argue for a diversity of earthquake-generation mechanisms as an impact of very variable systems of tectonic stresses, which are at the same time characterized by selectiveness in the orientations of the principal axis. We give stereographic models of earthquake-generation mechanisms, as well as the results from parameterization and structural kinematic identification of elements in the internal structure of seismogenic regions. We have identified a discrete character of earthquake-generating stress fields both with respect to the cardinal points (to the Earth’s axis of rotation) and with respect to the ground (horizontal) surface. We show that the diversity of seismogenic settings results from the transformations of stress fields that occur both at the regional and at local levels in the zones affected by the impact of major seismogenic structures in the study regions.