В работе показан характер мобилизации и концентрации рудных компонентов в условиях проявления современных вулканических процессов. Изложены результаты исследований, проведенных на действующих вулканах главным образом Курильских островов и Индонезии.

This report gives a brief description of field work on the Kuril Islands in summer 2021 carried out by staff of the Institute of Volcanology and Seismology of  FEB RAS within the framework of the Institute research theme and projects of the Russian Science Foundation (RSF) and Russian Fund for Basic Research (RFBR). To study chemical erosion of volcanic islands and to estimate hydrothermal export of magmatic volatiles, hydrological and hydrochemical works were carried out on the rivers draining the slopes and thermal fields of the Baransky volcano and the Bogdan Khmelnitsky volcanic massif (Iturup Island). Detailed hydrochemical studies with water sampling at different depths and a bathymetric survey of Lake Kipyashchey located in the caldera of Golovnin volcano (Kunashir Island) were performed. We also proceeded with studying the CO2 diffusion flux through thermal fields and volcanic lakes. In the course of ongoing regime observations on Ebeko volcano (Paramushir Island), aerial and infrared imaging of its near-crater part was carried out. For the first time since the eruption began in 2016, a quadcopter survey of the lake located in the Srednii (middle) crater of the volcano was conducted. For further analytical studies a large number of water and gas samples were taken, and the collection of sediments was replenished.

Based on the results of expeditionary studies (July 2021), geochemical features of thermal waters (natural manifestations and borehole waters) discharging near or directly on the Sea of Okhotsk and Pacific coasts of the central part of Iturup Island were considered: Reidovskie, Lososevye, Cape Konakov, Goryachie Klyuchi, Dachnye, water-recreational complex «Vannochki». The springs (with the exception of Lososevye) belong to subneutral Cl(Cl-HCO3)-Na waters with salinity less than 10 g/l. The Lososevye springs are of the weakly acidic HCO3-SO4-Ca-Na type with salinity of 3 g/l. The spontaneous gas is dominated by CO2 (Dachnye and Vannochki), N2 (Reidovskie and Cape Konakov) and CH4 (Goryachie Klyuchi). Against the background of a general extremely low content of microelements,  thermal waters are enriched with boron and lithium. The springs are characterized by small (0.1 l/s) to insignificant (0.02–0.05 l/s) flow rates, while wells drilled nearby uncover horizons of pressurized waters.

The actual collective monograph presents the results of both theoretical and experimental studies of the multi-disciplinary problem on volcanic hazard assessment and development of techniques for prediction of catastophic eruptions. The volcanism of Kamchatka and other regions of Russia has been analyzed. On the basis of geological, volcanological and tephrachronological studies including radiocarbon dating, there have been defined certain groups of volcanoes on different stages of evolution. At the same time the problem of determination of the internal structure of volcanic dome using modem theoretical methods and technologies is well investigated. The new techniques of estimation of volcanic hazard were developed. Whenever ti is required, theoretical approaches are confirmed by results of in-field observations.

The book will satisfy the needs of Earth sciences specialists from a variety of backgrounds, volcanology, geo-mechanics, ecology, industrial constuction applications and hazard assessment.