The reasons for enormous accumulation of the geodynamic tension in Eastern Turkey: a multidisciplinary study

Abstract

The catastrophic earthquakes in Eastern Turkey (Eastern Mediterranean) require their geodynamic understanding. The two most decisive events with magnitudes of 7.95 and 7.86 on 06.02.2023, followed by a series of more than 10,000 significant aftershocks. These tragic events led to the death of more than 60 thousand people. The above values indicate the colossal tension created in the Earth's crust. The region where these strongest earthquakes occurred is a complex junction zone of four tectonic plates: Eurasian, Arabian, African, and Anatolian. The joint movement of these plates (consisting, in turn, of tectonic elements of different ages) occurs at an average rate of 6-18 mm per year. After two marked powerful shocks and a series of aftershocks, some sectors of the Anatolian plate shifted to the southwest by more than 11 meters. Our recent publications indicated the presence of a giant, rotating quasi-ring structure below the Easternmost Mediterranean. This research contains significant newly obtained data. The quantitative analysis of the satellite-derived gravity data indicates the lower mantle occurrence of the anomalous target. Examination of the geoid anomalies map also testifies to the deep origin of this structure. The regional seismic tomography data confirm the presence of anomalous zones at a depth of 1500-1700 km. The GPS vector map and the comprehensive review of paleomagnetic data display the counterclockwise rotation of this structure. Analysis of the recently constructed magnetic field ΔZ pattern commonly proves the presence of this quasi-ring structure. The newly developed paleobiogeographic map is consistent with the proposed physical-geological model. A widespread analysis of tectonic, petrological, and mineralogical data implies a connection between the discovered deep structure and near-surface processes. A crucial for understanding the nature of the considered seismic stress is its location near the expressed bend of the Mesozoic terrane belt, where the Arabian Plate is deeply intruded into the Alpine-Himalayan belt. Thus, the rotation of this giant deep structure may accumulate the stress effect retrieved from the satellite, airborne, and surface geophysical observations. We propose that this stress, along with the known Earth's crust seismological activity in this region, is the causative reason for the catastrophic geodynamic events in Eastern Turkey.