Two powerful eruptions of Quizapu vent on Cerro Azul Volcano, Chile are used as examples to discuss the problem of effusive eruptions of magmas having high preeruptive volatile concentrations. A physicochemical mechanism is proposed for magma degassing, with the volatiles being lost before coming to the surface.
The model is based on the interaction of magmas residing in chambers at different depths and on the difference between the solubility of water in the melt and the water equilibrium concentration in a magma body having a considerable vertical extent. The shallower chamber can accumulate the volatiles released from the magma that is supplied from the deeper chamber. An explanation is provided of the dramatic differences in the character of the 1846–1847 and 1932 eruptions, which had identical chemical–petrographic magma compositions.

Изменение окружающей среды и климата: природные и связанные с ними техногенные катастрофы. Том II. Новейший вулканизм северной Евразии: закономерности развития, вулканическая опасность, связь с глубинными процессами и изменениями природной среды и климата. М., Изд-во ИГЕМ; 2008, с. 19-40

The Kamchatka branch of geophysical survey of RAS (KB GS RAS) is carry out a monitoring of activity of active volcanoes with the purpose of estimation of volcanic danger. One of the sections of observations is the satellite monitoring of thermal anomalies and ash plumes. They are based on a treatment and interpretation of satellite data information of AVHRR sensor of NOAA 16 and 17 satellites. The seismic monitoring is the main parameter for the volcano eruptions precursor as the most informative and authoritative method, because the quality of the seismic data is independent of the weather conditions. The seismic monitoring of the Bezymianny volcano is sometimes impossible or wrong. For the technical reasons or when strong seismic activity at the Klyuchevskoy volcano obscures the seismic data for the Bezymianny. So, the satellite monitoring of the thermal anomalies and research of its parameters are allows us to make a short-dated forecast for the Bezymianny volcano eruptions. The main aim of this article is an investigation of the thermal anomalies temperatures as a short-dated precursor for the Bezymianny volcano eruptions. There were 10 eruptions of the Bezymianny volcano in 2002-2007. The "normal", "higher" and "emergency" levels of anomaly temperatures with an allowance for the seasons of the year were separated. We separated such forecasting anomalies temperature values: "normal level" - is a temperature range, wherein the volcano activity on the ground level; "higher level" - is a temperature range, wherein the volcano prepare for any event (large rock fall, ash plume or eruption); "emergency level" - is temperature range, wherein the eruption will happen in the next 1-4 days. There are some criteria were mark out as a results of our researches. These criteria allow us to know the current status of volcano in presence using satellite data. The got information is compared with seismic, visual and video data, that allows us to trace the process of preparation of volcano to eruption much high-quality. The research results of the thermal anomaly temperatures are using as a secondary parameter to the seismic data for the Bezymianny volcano eruption precursor.

The paper describes petrophysical changes of Neogene-Quaternary volcanic rocks from Mutnovsky volcanic region under the action of hydrothermal processes. It was concluded that hydrothermal alterations lead to remarkable changes of physical and mechanical properties of rocks however the tendency of properties variation is different depending from a number of factors. Propylitization causes rocks consolidation, hardening, an increase of elastic properties, a decrease of porosity and disappearing of hygroscopic moisture. The influence of low-temperature fluids on the rocks is not so unequivocally. There can be a decrease as well as an increase of petrophysical properties. The sharp difference by properties, the structure of pore-space and the character and speed of hydrothermal alterations is observed between lavas and volcaniclastic rocks. However the primary differences between these rocks can disappear due to an intensive hydrothermal activity.

Одной из главных петрологических проблем вулканизма островных дуг является проблема его источника, так как ни один из наиболее распространенных типов высоко-глиноземистых базальтов, развитых в пределах этих структур не может быть получен непосредственным плавлением предполагаемого вещества мантии. Для Ключевской группы вулканов эта проблема стоит наиболее остро, так как здесь на ограниченной площади представлены продукты двух основных типов магм: известково-щелочной и субщелочной. По-видимому, решение проблемы лежит в возможности разноглубинного и частичного плавления вещества мантии и дальнейшего фракционирования и смешения магм в промежуточных магматических камерах. Изучение магматических очагов под Ключевской группой вулканов является одной из актуальных задач вулканологии, тесно связанной с проблемами геодинамики и прогнозом вулканических извержений.