Geodynamic features of the Central part of the Greater Caucasus according to GNSS observations

The Central part of the Greater Caucasus, as a part of the Alpine-Himalayan mobile belt, is a zone of complex tectonics associated with the interaction of the two major tectonic plates, Arabian and Eurasian. This work presents the strain rate and spatial distribution in the Central part of the Greater Caucasus. The assessments have been done based on long-term observations on the regional GNSS network, which currently consists of 7 continuous stations and 59 campaign sites. 45 IGS stations were used as the fiducial stations in the data analysis. The strain-rate tensor is calculated using the Shen method.

The results of our study show that, in general, this region is in the state of tectonic compression over which there are some features characteristics of particular structures of the region. The Main Caucasian Ridge and the trough of the southern slope are in the state of not only submeridional compression, but also sublatitudinal extension, which leads to an intensive dilatant expansion of the eastern segment of this area. The strain pattern of the northern part of the region differs from the southern one. The northern slope of the Main Caucasian Ridge zone and the foothill trough, including the Vladikavkaz fault zone, are in the state of compression with moderate intensity. At the same time, an analysis of the distribution of earthquake epicenters has shown that the Northern branch is currently aseismic in the central and eastern parts of the Vladikavkaz fault. This geodynamic feature indicates the high seismic potential of the Vladikavkaz Fault Zone.

This work is supported by the State assignment of the Vladikavkaz Scientific Center RAS, and partly by the Russian Foundation for Basic Research, grant no. 21-55-45007.