Study of modern regional and local anomal variations of seismicity in the Tavro-Caucasian region

The real-time monitoring of the seismicity of the territory of the Taurus-Caucasus region shows that at present, since 2021, geodynamic processes of significant intensity have been taking place in the earth's crust of the Taurus-Caucasus region, which can form anomalous areas of increased seismotectonic deformations on separate segments of seismically active faults. The article studies the activation of weak seismicity in the study area during the period of instrumental observations from 2021 to the present.  The structure of the set of sources of weak earthquakes in five-dimensional space (hypocenter, time, energy) is considered.  Based on the methods of statistical analysis of instrumental data, clusters of earthquake sources interconnected in space and time with magnitudes M≥3.0 (Figure 1).

Figure 1.

A detailed analysis shows that almost all types of anomalous manifestations of seismicity (swarms, earthquake doublets, pseudo-gaps, etc.) are observed in the same period in the Taurus-Caucasus region.  It was revealed that during the same period, the earthquake epicenters in real time line up mainly along trajectories that have a quasi-perpendicular direction with respect to the main seismically active faults of the Caucasus strike.  In the same period, in the Tavrokavkaz region, there is an alternation of seismotectonic stress variations in tense series of earthquakes in the magnitude range M=3.0-5.4 by sequential occurrence in the region of Eastern Turkey, Northern Armenia, Iran, Azerbaijan and the Greater Caucasus. The results obtained indicate that in the Taurus-Caucasus region there are regional and local significant changes in the stress-strain state of the earth's crust that are complex in their manifestation, which must be taken into account in a detailed study of seismic geodynamic processes in the Taurus-Caucasus region in order to identify possible zones of occurrence of strong earthquakes and medium-term earthquake forecast. This work was funded by the Science Committee of the Republic of Armenia, as part of the research project (No. ACH-01/22, 21SCG-1E021).