Group by:  
Records: 2508
Khubunaya S.A., Gontovaya L.I., Sobolev A.V., Khubunaya V.S. On the Magma Chambers beneath Klyuchevskoi Volcano, Kamchatka // Journal of Volcanology and Seismology. 2018. Vol. 12. № 2. P. 14-30. doi: 10.1134/80742046318020045.    Annotation
AAbstract—Numerous summit and parasitic eruptions of moderate potassium magnesian and high-alumina basalts and basaltic andesites, their mineralogic and geochemical features, and the composition of in situ chilled melt inclusions in the olivine of cinder lapilli discharged by Klyuchevskoi Volcano all provide evidence of the presence of magma chambers beneath the volcano. This is also supported by a dualism in the variation of CaO and A1203 concentrations in olivine and clinopyroxene during crystallization. The mineralogic features in the high-alumina basalts that were discharged by all parasitic eruptions of Klyuchevskoi provide evidence of magnesian magma being emplaced from a deeper chamber into a shallow high-alumina chamber. The distribution of incoherent elements in the volcano's magnesian and aluminiferous rocks shows that they came from a single mantle source. The geochemical and mineralogic data are in good agreement with the results of geophysical surveys that concern the structure and properties of the lithosphere beneath Klyuchevskoi.

Многочисленные вершинные и побочные извержения умереннокалиевых магнезиальных и высокоглиноземистых базальтов и андезибазальтов, их минералогические и геохимические особенности, состав природнозакаленных расплавных включений в оливинах шлаковых лапилли вулкана Ключевской свидетельствуют о наличии магматических очагов под вулканом. На это же указывает, дуализм в изменении содержаний СаО и А1203 в оливинах и клинопироксенах во время кристаллизации. Минералогические особенности высокоглиноземистых андезибазальтов, всех побочных извержений вулкана Ключевской свидетельствуют о внедрении магнезиальной магмы из глубинного очага в малоглубинную высокоглиноземистую камеру. Распределение некогерентных элементов в магнезиальных и глиноземистых породах вулкана указывает на их генезис из одного мантийного источника. Геохимические и минералогические данные находятся в хорошем соответствии с результатами геофизических исследований структуры и свойств литосферы под вулканом Ключевской.
Khubunaya S.A., Gontovaya L.I., Sobolev A.V., Nizkous I.V. Magma Chambers beneath the Klyuchevskoy Volcanic Group // Journal of Volcanology and Seismology. 2007. Vol. 1. № 2. P. 98-118. doi: 0.1134/S0742046307020029.    Annotation
A 3D velocity model of the Earth's crust beneath the Klyuchevskoy volcanic group has been constructed using the seismic tomography method. Anomalies of the velocity parameters related to the zones of magma supply to active volcanoes have been distinguished. Petrological data on the composition, temperature, and pressure of generation and crystallization of primary melts of Klyuchevskoy volcano magnesian basalts have been obtained. The primary melt corresponds to picrite (MgO = 13-14 wt %) with an ultimate saturation of SiO2 (49-50 wt %), a high H2O content (2.2-2.9%), and incompatible elements (Sr, Rb, Ba, Hf). This melt is formed at pressures of 15-20 kbar and temperatures of 1280--1320С . Its further crystallization proceeds in intermediate magma chambers at two discrete pressure levels (i.e., greater than 6, and 1-2 kbar). The results of the petrological studies are in good agreement with the seismotomographic model.

Поступила в редакцию 1. 11. 2006 г.
Методом сейсмической томографии построена объемная скоростная модель земной коры под Ключевской группой вулканов. Выделены аномалии скоростных параметров связанных с зонами магматического питания активных вулканов. Получены петрологические данные о составе, температуре и давлении генерации и кристаллизации родоначальных расплавов магнезиальных базальтов Ключевского вулкана. Родоначальный расплав отвечает пикриту (MgO=13-14%,мас) с предельным насыщением SiO2 (49-50%, мас.), высоким содержанием H2O (2,2-2.9%) и несовместимыми элементами (Sr, Rb, Ba, Hf). Он образуется при давлениях 15-20 кбар и температурах 1280-13200С. Его дальнейшая кристаллизация проходит в промежуточных магматических камерах при двух дискретных уровнях давлений (более 6 и 1-2 кбар). Результаты петрологических исследований находятся в хорошем соответствии с сейсмотомографической моделью.
Kirianov V.Yu. Assessment of Kamchatkan Ash Hazard to Airlines // Volcanology and Seismology. 1993. Vol. 14. № 3. P. 246-269.
Kirianov V.Yu. Volcanic Ash in Kamchatka as a Source of Potential Hazard to Air Traffic // Volcanic Ash and Aviation Safety: Proc. First Intern. Symp. on Volcanic Ash and Aviation safety. US Geological Survey Bull. US Geological Survey. 1994. Vol. 2047. P. 57-63.
Kirianov V.Yu., Egorova I.A., Litasova S.N. Volcanic ash on Bering Island (Commander Islands) and Kamchatkan Holocene Eruptions // Volcanology and Seismology. 1990. Vol. 8. № 6. P. 850-868.
Kirianov V.Yu., Melekestsev I.V., Andreev V.N., Ovsyannikov A.A. Reconstruction of the eruptive activity of Momotombo volcano (Nicaragua) to assess volcanic hazards // Kagoshima International Conference on Volcanoes: Proceedings of the International Conference on Volcanoes, Japan, Kagoshima, 19-23 July 1988. Kagoshima: Kagoshima Prefectural Government. 1988. P. 495-498.
Kirianov V.Yu., Neal C.A., Gordeev E.I., Miller T.P. The Kamchatkan Volcanic Eruption Response Team (KVERT) // USGS Fact Sheet. 2002. Vol. 064-02.
Kirianov V.Yu., Solovieva N.A. Lateral variations in ash composition due to Eolian differentiation // Volcanology and Seismology. 1991. Vol. 12. № 4. P. 431-442.
Kiryukhin A.V., Fedotov S.A., Kiryukhin P.A. Magmatic Systems and the Conditions for Hydrothermal Circulation at Depth in the Klyuchevskoi Volcanic Cluster as Inferred from Observations of Local Seismicity and Thermo-Hydrodynamic Simulation // Journal of Volcanology and Seismology. 2018. Vol. 12. № 4. P. 231-241. doi:10.1134/S0742046318040036.    Annotation
An analysis of local seismicity within the Klyuchevskoi Volcanic Cluster and Shiveluch Volcano for the period 2000–2017 revealed a sequence of plane-oriented earthquake clusters that are interpreted here as the emplacement of dikes and sills (magmatic fracking). The geometry of magma bodies reflects the geomechanical conditions in volcanic plumbing systems and at the bases of the volcanoes. Magmatic fracking within active magmatic plumbing systems results in the formation of permeable reservoirs whose vertical extent can reach 35 km (Klyuchevskoi) and can be as wide as 15 km across (Shiveluch), depending on the geomechanical condition of the host rocks. These reservoirs will be the arena of subsequent hydrothermal circulation, producing geothermal and ore fields, as well as hydrocarbon fields. TOUGH2-EOS1sc simulation tools were used to estimate the conditions for the formation of hydrothermal reservoirs at temperatures below 1200°С and pressures below 1000 bars.
Kiryukhin A.V., Fedotov S.A., Kiryukhin P.A., Chernykh E.V. Magmatic plumbing systems of the Koryakskii–Avacha Volcanic Cluster as inferred from observations of local seismicity and from the regime of adjacent thermal springs // Journal of Volcanology and Seismology. 2017. Vol. 11. № 5. P. 321-334. doi:10.1134/S0742046317050049.    Annotation
An analysis of local seismicity within the Avacha–Koryakskii Volcanic Cluster during the 2000–2016 period revealed a sequence of plane-oriented earthquake clusters that we interpret as a process of dike and sill emplacement. The highest magmatic activity occurred in timing with the 2008–2009 steam–gas eruption of Koryakskii Volcano, with magma injection moving afterwards into the cone of Avacha Volcano (2010–2016). The geometry of the magma bodies reflects the NF geomechanical conditions (tension and normal faults, Sv >SHmax >Shmin ) at the basement of Koryakskii Volcano dominated by vertical stresses Sv, with the maximum horizontal stress SHmax pointing north. A CFRAC simulation of magma injection into a fissure under conditions that are typical of those in the basement of Koryakskii Volcano (the angle of dip is 60о, the size is 2 × 2 km2, and the depth is –4 km abs.) showed that when the magma discharge is maintained at the level of 20000 kg/s during 24 hours the fissure separation increases to reach 0.3 m and the magma injection is accompanied by shear movements that occur at a rate as high as 2 × 10–3 m/s, thus corresponding to the conditions of local seismic events with Mw below 4.5. We are thus able to conclude that the use of planeoriented clusters of earthquakes for identification of magma emplacement events is a physically sound procedure. The August 2, 2011 seismicity increase in the area of the Izotovskii hot spring (7 km from the summit of Koryakskii Volcano), which is interpreted as the emplacement of a dike, has been confirmed by an increase in the spring temperature by 10–12°С during the period from October 2011 to July 2012.