The results of geological and geophysical studies, including recent ones, which make it possible to verify the existence of a liquid magma chamber below the Avachinsky volcano on Kamchatka, and to estimate the chamber depth and approximate dimensions, are analyzed. The heat stored in the host rock heated by the volcanic magma chamber from the time of chamber origination to the present is estimated, taking variable chamber dimensions during the process of evolution into account. The geological-geophysical prerequisites for using the thermal energy of the heated rock which surrounds the magma chamber to supply heat and power to Petropavlovsk-Kamchatskii are analyzed. The creation of an underground geothermal circulation system (fracture heat exchanger) using deep boreholes is proposed.

Based on the study of the waveforms and spectral composition of earthquakes recorded during the activation of Avachinsky volcano in 2019, three generally accepted types of volcanic earthquakes (VE) were identified: volcano-tectonic, hybrid and long-period, as well as the fourth – a “special” type of VE, characterized by differ of waveforms. 15 plane-oriented clusters have been identified and the characteristics of seismogenic areas
have been determined. Analysis of the seismic events recorded in autumn 2019 in the Young Cone of Avachinsky Volcano suggested a connection between the activation of the 1991 eruption in the body of the cone and their interaction with atmospheric precipitation with magmatic bodies. The most likely cause of the light flashes over the crater on December 8 is the interaction of a hydrogen-rich volcanic gas in contact with atmospheric oxygen.

Seismic activation of Avachinsky volcano was observed from late October to late December 2019, when 6 swarm sequences of volcanic earthquakes of various types occurred in its construction. In the swarm sequences, 15 plane-oriented clusters were identified and the characteristics of their seismogenic areas were determined. A comprehensive analysis of seismic events indicates that the activation of Avachinsky volcano at the end of 2019 arose because of the interaction of meteoric waters with magmatic bodies in the body of the cone, which arose during an effusive eruption in 1991.