The paper describes the analysis of global data on the isotopic composition of waters from about 120 world surface mud volcanoes. Frequency distribution for δ18O is bimodal, the most frequent values lie within the intervals (+1; +2)‰ and (+5; +6)‰. Frequency distribution for δD is asymmetric with a maximum lying within the range (−15; −10)‰. Midline angle factor of isotopic composition on the δ18O−δD diagram is close to 1. The authors suppose that the variety of isotopic composition of the mud volcanic waters is determined mainly by two processes: mixing of initial seawater with water formed during the dehydration of clay minerals and dilution by meteoric waters. The first process occurred predominantly on the stage of formation of mud volcanoes in the geological past, while the second process occurs on the modern stage of activity of mud volcanoes.

The article presents the methods and results of the magnetotelluric sounding within the Avacha-Koryaksky group of volcanoes. Geoelectrical section was studied within the period range from 0.0001 to 1000 seconds and above. The authors performed a numerical two-dimensional modeling. Initially, we used test models for possible distortions of curves. The analysis of the magnetotelluric parametres allowed us to characterize the geoelectrical inhomogenuities. Curves along the strike and across the strike were used as main curves. Since longitudinal curves are less prone to coast effect, they were used with transverse curves in order to create a geoelectrical model based on a 2D magnetotelluric field numerical modeling. The created geolectrical model has a conductive bed in the upper part of the section that is connected with an igneous-sedimentary cover. The deep part of the model includes near-vertical conductive zones, which denote a zone with deep faults. The paper describes possible nature of the revealed anomalies and provides rough estimation of rock porosity in the conductive zones.

A velocity structure of the lithosphere has been determined in the junction area of the Kuril-Kamchatka and Aleutian island arcs based on travel times of compressional (P) and shear (S) waves excited by regional and volcanotectonic earthquakes using the algorithm of successive anomaly subtraction. We describe deep-seated velocity heterogeneities at different depths in the lithosphere, their relation to tectonics and to seismicity. It is shown that the deep-seated source of magma supply for the Klyuchevskoi volcanic cluster is confined to a junction of deep-seated mantle faults (in map view this occurs at the location where the Kamchatka R. streambed turns eastward). The heterogeneity in question probably has asthenospheric roots. The crustal velocity structure beneath Klyuchevskoi Volcano together with data provided by other geological and geophysical methods (deep seismic sounding, electromagnetic methods, lineament analysis etc.) provides an idea of the model and of a general view of the tectonomagmatic processes going on there.