STRUCTURE OF THE UPPER CRUST BENEATH THE KAMBALNY VOLCANO (SOUTH KAMCHATKA) REVEALED FROM AMBIENT NOISE TOMOGRAPHY
The paper presents result of ambient noise tomography for the Kambalny volcano (South Kamchatka), where the first in the entire history of observations, powerful phreatic eruption was observed in March–April 2017. The obtained results clarify the structure of the upper part of the edifice of Kambalny Volcano and are consistent with independent results on body waves, as well as with geological information. In the model of the structure of the volcanic edifice, according to seismotomographic results from surface waves, low-velocity anomalies are distinguished asymmetrically relative to the volcano’s cone, confined to loose pyroclastic deposits of past eruptions and to deep sources of hydrothermal activity. Perhaps the migration of fluids in these hydrothermal vents to the north and west of the volcano and their interaction with the magma chamber in the upper crust caused the explosive eruption.