Purpose. To investigate structure-tectonic and faults features of the central part of the Transcarpathian internal depression and their relations with earthquake epicenters localization and peculiarities of seismic waves spreading on the base of instrumental observations in regime geophysical observatories of the Carpathian geodynamic polygon. Methods and results. The study developed methodology for specification of local earthquake focus depths by means of neuron-network modeling, computer processing and systematization of observation data at the Carpathian geodynamic network and adjusting areas on the basis of recent mapping and graphical information. On the examples of earthquakes registered by the regime geophysical station “Mukachevo”, focal mechanisms of earthquakes were determined using first arrival polarities. Scientific novelty. The research determined the relationships between structural and tectonic features in the central part of the Carpathian backdeep, the recent geodynamics of the region’s basement, peculiarities of seismic waves spreading, and formation of local earthquake focuses. It was stated that the influence of the igneous rocks of the Vyhorlat-Hutyn volcanic ridge significantly reduced the time of seismic waves passing in the sedimentary layer and partly in the basement. To determine a focal mechanism of the earthquake, the velocity of seismic waves in the layers should be taken into account on a case-by-case basis, taking into account the location of seismic stations with respect to deep and surface faults and the impact of volcanic rocks, and not using standard velocity models for seismic stations resulting from the stations that give significant results in calculations of output seismic wave angle and facilitate the selection of nodal surfaces. Practical value. Detailed investigations allow determining characteristics of earthquake epicenters, velocities and direction of seismic waves spreading in accordance with the structure of the basement and sedimentary layer. This will, in turn, provide an opportunity to supplement the data of long-term monitoring of natural and technological hazards in the region.
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