The paper discusses the mechanism of deep magma activity beneath island are volcanoes and similar structures on the basis of data from geophysical investigations in Kamchatka; the analyses of forces that cause the ascent of magma; and related phenomena that are due to hydrostatic forces.
It is shown that the ascent of magma through the astnenosphere occurs most likely in magma columns with a diameter of approximately 700–2,000 m and with a velocity of about 0.8–3 m/year. A regular line of such columns spaced in Kamchatka at a distance of about 30 km gives rise to a chain of separate Etrge volcanoes or volcanic centers.
Ultrabasic magmas are most likely accumulated near the M discontinuity, whereas the apparent place of andesitic magma accumulation is in the earth’s crust near the boundary between the basement and sediments.

Lithospheric mantle is inferred to be more oxidized than the asthenosphere, and mantle-wedge peridotites are characterized by high oxidation state relative to abyssal and continental peridotites due to addition of slab-derived fluids or melts. We found metals (native Ni, Fe silicides, native Fe and possible native Ti) from otherwise oxidized sub-arc mantle peridotite xenoliths from Avacha volcano, Kamchatka. This is contrary to the consensus and experimental results that the metals are stable only in deeper parts of the mantle (> 250 km). The metals from Avacha are different in chemistry and petrography from those in serpentinized peridotites. The Avacha metals are characteristically out of chemical equilibrium between individual grains as well as with surrounding peridotite minerals. This indicates their independent formation from different fluids. Some of the Avacha metals form inclusion trails with fluids and pyroxenes, leading to the inference that very local metal saturation resulted from rapid supply (‘flashing’) of reducing fluids from deeper levels. The fluids, possibly rich in H2, are formed by serpentinization at the cold base of the mantle wedge just above the slab, and they reduce overlying peridotites. We propose a metal-saturated peridotite layer, underlying the main oxidized portion, within the mantle wedge beneath the volcanic front to fore-arc region.

Study is made for the first time on morphological peculiarities of microstructure of three samples from the unbroken marker ash layers of the Shiveluch volcano. In this paper we give the qualitative analysis of tephra structure, i.e. size and shape of particles and type of microstructure, describe structural relationships between deposit components, etc. and make the quantitative analysis of porosity of Sh2 and Sh1 tephra at magnification of 200 and 1,000. Hollow globules of volcanic glass were found for the first time in Sh2 ashes.

Publications about the earthquake foci migration have been reviewed. An important result of such studies is establishment of wave nature of seismic activity migration that is manifested by two types of rotational waves; such waves are responsible for interaction between earthquakes foci and propagate with different velocities. Waves determining long-range interaction of earthquake foci are classified as Type 1; their limiting velocities range from 1 to 10 cm/s. Waves determining short-range interaction of foreshocks and aftershocks of individual earthquakes are classified as Type 2; their velocities range from 1 to 10 km/s. According to the classification described in [Bykov, 2005], these two types of migration waves correspond to slow and fast tectonic waves. The most complete data on earthquakes (for a period over 4.1 million of years) and volcanic eruptions (for 12 thousand years) of the planet are consolidated in a unified systematic format and analyzed by methods developed by the authors. For the Pacific margin, Alpine-Himalayan belt and the Mid-Atlantic Ridge, which are the three most active zones of the Earth, new patterns of spatial and temporal distribution of seismic and volcanic activity are revealed; they correspond to Type 1 of rotational waves. The wave nature of the migration of seismic and volcanic activity is confirmed. A new approach to solving problems of geodynamics is proposed with application of the data on migration of seismic and volcanic activity, which are consolidated in this study, in combination with data on velocities of movement of tectonic plate boundaries. This approach is based on the concept of integration of seismic, volcanic and tectonic processes that develop in the block geomedium and interact with each other through rotating waves with a symmetric stress tensor. The data obtained in this study give grounds to suggest that a geodynamic value, that is mechanically analogous to an impulse, remains constant in such interactions. It is thus shown that the process of wave migration of geodynamic activity should be described by models with strongly nonlinear equations of motion.