Institute of Volcanology and Seismology
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Overview of the precursors and dynamics of the 2012–13 basaltic fissure eruption of Tolbachik Volcano, Kamchatka, Russia
No full textAbstract We present a broad overview of the 2012–13 flank fissure eruption of Plosky Tolbachik Volcano in the central Kamchatka Peninsula. The eruption lasted more than nine months and produced approximately 0.55 km3 {DRE} (volume recalculated to a density of 2.8 g/cm3) of basaltic trachyandesite magma. The 2012–13 eruption of Tolbachik is one of the most voluminous historical eruptions of mafic magma at subduction related volcanoes globally, and it is the second largest at Kamchatka. The eruption was preceded by five months of elevated seismicity and ground inflation, both of which peaked a day before the eruption commenced on 27 November 2012. The batch of high-Al magma ascended from depths of 5–10 km; its apical part contained 54–55 wt. SiO2, and the main body 52–53 wt. SiO2. The eruption started by the opening of a 6 km-long radial fissure on the southwestern slope of the volcano that fed multi-vent phreatomagmatic and magmatic explosive activity, as well as intensive effusion of lava with an initial discharge of > 440 m3/s. After 10 days the eruption continued only at the lower part of the fissure, where explosive and effusive activity of Hawaiian–Strombolian type occurred from a lava pond in the crater of the main growing scoria cone. The discharge rate for the nine month long, effusion-dominated eruption gradually declined from 140 to 18 m3/s and formed a compound lava field with a total area of ~ 36 km2; the effusive activity evolved from high-discharge channel-fed 'a'a lavas to dominantly low-discharge tube-fed pahoehoe lavas. On 23 August, the effusion of lava ceased and the intra-crater lava pond drained. Weak Strombolian-type explosions continued for several more days on the crater bottom until the end of the eruption around 5 September 2013. Based on a broad array of new data collected during this eruption, we develop a model for the magma storage and transport system of Plosky Tolbachik that links the storage zones of the two main genetically related magma types of the volcano (high-Al and high-Mg basalts) with the clusters of local seismicity. The model explains why precursory seismicity and dynamics of the 2012–13 eruption was drastically different from those of the previous eruption of the volcano in 1975–76
Комплексные геолого-геофизические исследования подводных вулканов Курильской островной дуги в 2014–2015 гг.
No full textThe geodynamic setting in the northwest circumference of the Pacific Ocean: Effects on the dynamics of subsurface radon and on the gas composition of the heat carrier at the Mutnovskii geoelectric power station
No full textThis paper provides information on the behavior of the radon activity time series for the period from 2000 through 2015 in the water-saturated zone of the Paratunka Geothermal Field and that of the time series that recorded the volumetric fraction of molecular hydrogen in the gaseous heat carrier at well 016 in the Mutnovskii Field, as well as their relationships with the seismicity in the northwestern circumference of the Pacific Ocean. It was concluded that long-term trends in radon activity and the high volumetric fraction of molecular hydrogen in 2014 are caused by a change in the stress field that acts in the subduction zone of the northwest flank of the Pacific Ocean. It is hypothesized that an M > 7.5 earthquake is likely to occur during the next 1.5 years. In the opinion of Academician S.A. Fedotov, the most likely location for such an event is between the Shipunskii Peninsula and Shiashkotan Island, Middle Kuril islands
Геодинамические условия образования адакитов и NB-обогащенных базальтов (NEAB) на Камчатке
No full textKhankala thermal water deposit of the Chechen Republic and resources for the implementation of geothermal circulatory systems
No full textIn the article, the perspective development of geothermal resources in the Chechen Republic is considered and data on the perspective Khankala deposits of thermal waters is stated. For the estimation on the feasibility of the creation of circulatory systems, the authors have created a 3D model of the most productive XIII layers of this deposit. This allows for proposals of possible locations of water-intake and water injection wells. In conclusion, recommendations for the location of the wells and the creation of a circulatory scheme of intake of deep heat in the Khankala deposit of thermal waters are given
Petrological study of monogenetic volcanoes in the fore-arc region of the northern Kamchatka Peninsula
No full textThe western part of the Pacific Plate is subducting under the Okhotsk Plate along Kuril-Kamchatka Trench, and the northern part of it is subducting under the Bering Sea Plate with high obliquity along the western Aleutians arc. The three plates form the Aleutian-Kamchatka triple junction (Eichelberger et al., 2013). The northern edge of the Pacific Plate is separated from Bering Sea Plate by transform fault, and the mantle edge beneath the Kamchatka Peninsula is thought to be open towards the Bering Sea
Гидрогеохимия западного склона вулкана Кунтоминтар (о. Шиашкотан, Курилы)
Get PDFНа основе гидрогеохимических данных, полученных в результате полевых работ, проведенных на острове Шиашкотан в 2011 г., приводится характеристика различных типов природных вод, включая конденсат фумарольных газов, разгружающихся на западном склона вулкана Кунтоминтар. В исследуемом районе распространены холодные и термальные кислые минерализованные воды, соответствующие сульфатному типу с пестрым катионным составом. Конденсат фумарольных газов относится к хлоридному кальциевому типу с высоким содержанием бора. Формирование химического состава природных вод происходит за счет взаимодействия метеорных вод с гидротермально измененными породами. Газы вулкана Кунтоминтар имеют магматическое происхождение: их конечный состав сформирован в результате подъема флюида к поверхности и значительного разбавления его метеорной водой в близповерхностных условиях
On Some Features Peculiar to the September 22, 2005 Eruption of Young Shiveluch Volcano, Kamchatka
No full textAn explosive eruption of Young Shiveluch Volcano occurred on September 22, 2005, discharging a pyroclastic flow about 20 km long in the Baidarnaya River valley and an ashfall in the area of the Northern group of volcanoes
