The article presents new data on magmatic rock composition from the Stolbovaya formation, Kamchatsky Mys Peninsula. The studied rocks belong to high alumina tholeiitic island arc series and their geochemical characteristics are identical to those from Kronotskaya formations in Kronotsky Peninsula. Magmanicsedimentary complexes of the Stolbovskaya formations were deposited within the volcanic archipelago of the Kronotsky volcanic arc. Geochemical and isotopic data from the studied rocks give evidence that they were formed from a depleted mantle source. The certain observed differences in Eocene rock composition from Kamchatsky Mys and Kronotsky peninsulas are likely caused by differences in fluid regime.

The items of information about eruptions activity of Ebeko volcano in 2010-2011 are resulted. In 2010 from eruption funnel of Northern crater there were two weak short-term explosive eruptions. The eruption was phreatic, the cast out products are submitted by resurgent ashes. Volumes of the thrown out material ~ 1.2 t and ~ 95 t accordingly. All eruptions were anticipated by changes in chemical structure of fumarole gases, before eruption of July 2, 2010 the seismic harbingers were observed. In July, 2011 there was a series of hydrothermal explosions on the average crater of a volcano. The morphological changes have bottom and southwest wall of a crater. The maximal range ejection of ashes did not exceed 560 m.

A chronologic description of Shiveluch eruptions is presented for the recent 2001-2004 eruptive cycle. The data described include visual and seismological observations, determinations of the heights and volumes of the extrusive domes derived by geodetic techniques. Increasing seismicity was identified in the crater as it was being filled with extrusive domes. Products of volcanic eruptions occurring during the recent eruptive cycle have been studied. It is shown that the chemical and mineral composition of the volcanic products changed during several eruptive cycles.

The evolution of the Quaternary Kekuknai volcanic massif (the western flank of the Sredinnyi Range in Kamchatka) has been subdivided into five stages: (I) the pre-caldera trachybasalt- basaltic andes- ite, (2) the extrusive trachyandesite-trachydacite, (3) the early trachybasalt, (4) the middle hawaiite- mugearite (with occasional occurrences of basaltic andesites), and (5) the late trachybasalt-hawaiite- mugearite (with occasional andesites) of areal volcanism. On the basis of petrologic data we identified the island arc and the intraplate geochemical types of rocks in the massif. The leading part in petrogenesis was played by dynamics of the fluid phase with a subordinated role of fractional crystallization and hybridism. Successive saturation of rocks with the fluid phase in the course of melt evolution stopped at the time of caldera generation when most fluid mobile elements and silica had been extracted. The geological and petrologic data attest to the formation of the massif in the environment of a backarc volcanic basin during the beginning of rifting with active participation of mantle plume components.

The Kekuknai massif was formed in the course of tectono-magmatic activity that involved the origin of a shield volcano and a caldera depression with associated emplacement of extrusions that terminated in intense post-caldera areal volcanism. The mineralogical compositions of the massifs rocks have been considered in detail. The use of previously known and newly developed indicator properties of rock-forming minerals allowed the reconstruction of the general picture of the magmatic melt evolution and conditions of rock crystallization (various fluid and water saturation levels, as well as the oxidation state of the system). Essentially island-arc or intraplate characteristics of the massif s rock compositions are found at different stages of development of a single fluid-magmatic system. Decompression evolution of the parent deep-seated basanitic magma occurred via occurrence in intermediate magma chambers of daughter magmas of trachybasalt (pre-caldera stage) or hawaiite (areal volcanism) composition. Subsequent emanate-magmatic differentiation of these melts, combined with crystallization differentiation under changing P-T-f0l conditions, resulted in the formation of the entire diversity of the Kekuknai rocks