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

Mutnovsky Volcano is characterized by predominantly magmatic activity for the last 4 thousand years in the northern sector where the Mutnovsky geothermal field lies. Magmatic activity is identified using the Frac-Digger method based on seismic data as reported by the KB FRC UGS RAS. The most significant sequence of shallow dikes striking northeast has been manifested at the surface by blowing two-phase geothermal wells. Dike emplacement in March 2024 was synchronized with a hydrothermal explosion producing a crater of volume reaching 0.36 million m3 at the place of well 022 (Crater 022+). Unaltered fragments due to the explosion indicate a lithoclastic character in the gas-enriched head of the dike. The bottom of the explosion crater is a hydrothermally altered (opal, zeolite) 160 × 75 m2 in area. The mechanism of the hydrothermal explosion is treated as resulting from hydraulic fracturing by means of a shallow dike, with subsequent increase in pressure in the shallow geothermal reservoir near the well with a closed wellhead control-valve.