Magmatic Activity of Mutnovsky Volcano and Crater Formation at the Site of Blowing Well 022

Mutnovsky volcano in the last four thousand years is characterized by predominantly magmatic activity in the northern sector, where the Mutnovsky geothermal field was formed. Magmatic activity is detected by the Frac-Digger method using seismic data of KF FIC EGS RAS, the most powerful sequence of shallow dykes of NE strike is manifested at the surface by blowing geothermal wells. Dyke emplacement in March 2024 is synchronized with a hydrothermal explosion with the formation of a crater with a volume of up to 0.36 million m3 at the site of well 022 (Crater 022+). Unaltered debris from the explosion indicates lithoclastic character in the head gas-saturated part of the dyke. The base of the explosion crater is a hydrothermally altered (opal, zeolites) plane of 160×75 m2. The mechanism of the hydrothermal explosion is considered as a result of hydraulic fracturing of the two-phase geothermal reservoir by a shallow dyke, with subsequent pressure increase in the shallow hydrothermal reservoir near the well with a closed wellhead valve.