Seismic Tomography of Kamchatkan Volcanoes

Abstract

Abstract —The Kamchatka Peninsula is one of the most tectonically active regions in the world, where intensive and diverse modern volcanic activity takes place. In the recent decade, substantial progress in the investigation of deep structures beneath Kamchatka has been achieved owing to numerous tomography studies based on seismological data provided by permanent stations and temporary networks deployed in some key areas. The goal of this review is summarizing and systematizing dozens of separate multiscale geophysical studies in Kamchatka and constructing an integral model of volcano-feeding systems. An important part of this review contains the description of results of various seismic studies related to the Klyuchevskoy group volcanoes, which can now be considered one of the best studied volcanic areas in the world. The results of the regional-scale seismic tomography reveal the existence of the Pacific slab window, which determines the particular activity of the Klyuchevskoy group volcanoes. Middle-scale tomography studies have found traces of an ascending hot mantle flow that passes through the slab window, reaches the bottom of the crust below Shiveluch Volcano, and then propagates laterally toward the Klyuchevskoy group. Seismic models of the entire crust in the area of the Klyuchevskoy group were used to identify different mechanisms of magmatic feeding of three most active volcanoes: Klyuchevskoy, Bezymianny, and Tolbachik. The data of local networks deployed on several volcanoes of Kamchatka were used to image the magma sources in the upper crust, which are directly responsible for the current eruption activity. The comparison of the results for the Kamchatka volcanoes with tomography models of several other volcanoes of the world allowed determining some common features and differences in feeding active magmatic systems.