Submarine Volcano 8.10 (Kuril Island Arc)

Abstract

Submarine volcano 8.10, which is part of the South Iturup group of submarine volcanoes in the Kuril Island Arc (KIA), was studied using a proven technology of quantitative interpretation of hydromagnetic survey materials in combination with echo sounding, continuous seismoacoustic profiling, and analysis of petromagnetic properties and chemical composition of dredged rocks. The technology makes it possible to interpret directly from the original data without resorting to the procedure of their preliminary restoration in the nodes of a regular grid. The studies found that dredged andesite-basalts and andesites are representatives of different lava flows that have a single magma source but differ in the conditions and dynamics of crystallization. The main carrier of the natural residual magnetization of andesite-basalts is titanomagnetite with low Ti content and that for andesites is magnetite. Feeding channels and peripheral magma chambers are identified in the volcanic edifice. Submarine volcano 8.10 and other studied KIA volcanoes formed during geomagnetic inversions. The presence of hydroacoustic anomalies at the top of the volcano indicates that manifestations of underwater gas-hydrothermal activity in the southern part of the KIA are more significant than was thought until recently.