Institute of Volcanology and Seismology
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Голоценовое эксплозивное извержение на перешейке Ветровой (о. Итуруп) как источник маркирующего горизонта тефры (~2000 лет назад) в центральной части Курильской островной дуги
No full textConnections between arc volcanoes in Central Kamchatka and the subducting slab inferred from local earthquake seismic tomography
Get PDFThe area of Central Kamchatka limited by latitudes of 52.5 and 54 degrees includes six active volcanoes (Avacha, Koryaksky, Zhupanovsky, Mutnovsky, Gorely and Opala), as well as a number of dormant and extinct stratovolcanoes, monogenic cones and large calderas. Furthermore, it contains the Malko-Petropavlovsk fracture zone (MPZ), which marks the boundary between two distinct subduction regimes to the south and to the north. We present a new seismic tomography model for this area, which was constructed based on the joint use of data of the Kamchatkan permanent seismic stations and a temporary network installed in the region in 2019–2020. A series of synthetic tests have demonstrated fair resolution of the derived seismic velocity structures in the crust and in the mantle wedge down to ~150 km. The distributions of the P and S wave velocities, and especially the Vp/Vs ratio, clearly highlight the connection between the volcanic centers in Central Kamchatka and the subducting slab. At depths below 40 km depth, we observe two large low-velocity anomalies centered below Zhupanovsky and Mutnovsky volcanoes and covering all other volcanoes in the area. In the vertical sections, the corresponding anomalies of high Vp/Vs ratio have mushroom shapes with the heads spreading along the bottom of the crust, which probably represent the underplating of magma material that feeds the volcanoes of the groups. The tomography results also reveal some important tectonic features, such as a V-shaped fault system in the Avacha Graben, which is the part of the MPZ
The Petrophysical Properties and Strength of Extrusive Rocks Discharged by Bezymianny Volcano, Kamchatka
No full textThis is the first petrophysical study of extrusive rocks (dacites to andesites) discharged by Bezymianny Volcano. We provide a comparative description of properties for extrusive rocks in accordance with identified age groups. We show the dynamics in the variation of extrusive rock properties in relation to their ages, with the result that the older a rock the higher are its density, strength, and elastic parameters. Rocks petrophysical features are compared between extrusive domes and lava flows. We argue for petrophysical properties to be applicable for deriving more accurate results for the genesis of rocks having similar petrophysical properties, in particular, rocks of extrusive and effusive origin
Transition from the Continental Margin of Kamchatka to the Island Arc of the Kurile Islands: Features of Volcanism, Crustal Deformation and Geophysical Parameters of the Slab
No full textMonitoring the Thermal Activity of Kamchatkan Volcanoes during 2015–2022 Using Remote Sensing
Get PDFThe powerful explosive eruptions with large volumes of volcanic ash pose a great danger to the population and jet aircraft. Global experience in monitoring volcanoes and observing changes in the parameters of their thermal anomalies is successfully used to analyze the activity of volcanoes and predict their danger to the population. The Kamchatka Peninsula in Russia, with its 30 active volcanoes, is one of the most volcanically active regions in the world. The article considers the thermal activity in 2015–2022 of the Klyuchevskoy, Sheveluch, Bezymianny, and Karymsky volcanoes, whose rock composition varies from basaltic andesite to dacite. This study is based on the analysis of the Value of Temperature Difference between the thermal Anomaly and the Background (the VTDAB), obtained by manual processing of the AVHRR, MODIS, VIIRS, and MSU-MR satellite data in the VolSatView information system. Based on the VTDAB data, the following “background activity of the volcanoes” was determined: 20 °C for Sheveluch and Bezymianny, 12 °C for Klyuchevskoy, and 13–15 °C for Karymsky. This study showed that the highest temperature of the thermal anomaly corresponds to the juvenile magmatic material that arrived on the earth’s surface. The highest VTDAB is different for each volcano; it depends on the composition of the eruptive products produced by the volcano and on the character of an eruption. A joint analysis of the dynamics of the eruption of each volcano and changes in its thermal activity made it possible to determine the range of the VTDAB for different phases of a volcanic eruption
Мониторинг пароксизмального извержения вулкана Шивелуч 10-13 апреля 2023 г. дистанционными методами
No full textMagmatic system of the Klyuchevskoy volcano according to seismic data and their geomechanical interpretation
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