Institute of Volcanology and Seismology
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Slab-mantle thermal structure beneath northeast Kamchatka Peninsula constrained from high-Mg basalts and andesites
No full textОбъемы четвертичных вулканитов Курильской островной дуги: анализ пространственного расположения и связь с зоной субдукции
No full textThe Geodynamic Conditions for the Generation of Adakites and Nb Rich Basalts (NEAB) in Kamchatka
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Infrasound from the 2012–2013 Plosky Tolbachik, Kamchatka fissure eruption
No full textAbstract We use both regional and local infrasound data to investigate the dynamics of the 2012–2013 eruption of Tolbachik Volcano, Kamchatka, Russia during select periods of time. Analysis of regional data recorded at the {IMS} array {IS44} in southern Kamchatka, ~ 384 km from the vent focuses on the eruption onset in November 2012, while analysis of local data focuses on activity in February and August 2013. Signals recorded from Tolbachik suggest a change in eruptive intensity possibly occurred from November 27–30, 2012. Local infrasound data recorded at distances of 100–950 m from the vent are characterized primarily by repeated, transient explosion signals indicative of gas slug bursts. Three methods are employed to pick slug burst events in February and August. The nature of slug bursts makes a monopole acoustic source model particularly fitting, permitting volume outflux and slug radius calculations for individual events. Volume outfluxes and slug radii distributions provide three possible explanations for the eruption style of Tolbachik Volcano from mid-February to late August. Cumulative outflux for slug bursts (i.e. mass of emissions from individual bursts) derived by infrasound for both February and August range from < 100 to ~ 3000 kg. These values are greater than infrasound-derived emissions calculated at Pacaya Volcano, but less than those calculated at Mt. Erebus Volcano. From this, we determine slug bursts at Tolbachik Volcano in February and August were larger on average than those at Pacaya Volcano in 2010, but smaller on average than those at Mt. Erebus in 2008. Our overall emissions estimates are in general agreement with estimates from satellite observations. This agreement supports the monopole source inversion as a potential method for estimating mass of emissions from slug burst events
Monitoring of the volcanic rock compositions during the 2012–2013 fissure eruption at Tolbachik volcano, Kamchatka
No full textAbstract Here we present the results from monitoring of the composition of rocks produced during the 2012–2013 fissure eruption at Tolbachik volcano (FTE). Major and trace element concentrations in 75 samples are reported. Products of this eruption are represented by high alumina basaltic trachyandesites with higher alkalis and titanium contents than in all previously studied rocks of the Tolbachik monogenetic volcanic field. Rocks erupted during the first three days (27–30 November) from the northern (also called Menyailov) group of vents are the most silica- and alkali-rich (SiO2 concentrations up to 55.35 wt. and {K2O} up to 2.67 wt.). From December onwards, when the eruptive activity switched from the Menyailov vents to the southern (Naboko) group of vents, silica content dropped by 2 wt., concentrations of MgO, FeO, TiO2 and Mg# increased, and {K2O} and Na2O concentrations and K2O/MgO ratio decreased. For the rest of the eruption the compositions of rocks remained constant and homogeneous; no systematic compositional differences between lava, bombs and scoria samples are evident. Trace element distributions in the rocks of the Menyailov and Naboko vent lavas are relatively uniform; Menyailov lavas have slightly higher Th, Nb, Hf, Y, and {HREE} concentrations than the Naboko vent lavas at more or less constant element ratios. We explain the initial change in geochemistry by tapping of a slightly cooler and fractionated (~ 3 Mt and 8 Cpx) upper part of the magma storage zone before the main storage area began to feed the eruption. Thermodynamic constraints show that apparent liquidus temperatures varied from 1142 °C to 1151 °C, and thermodynamic modeling shows that variations in compositions are consistent with a high degree of low pressure (100–300 MPa), nominally anhydrous fractionation of a parent melt compositionally similar to the 1975 Northern Breakthrough high-Mg basalt. Geochemistry, petrological observations and modeling are in agreement with the newly erupted material being derived from remnant high-Al magma from the 1975–76 Southern Breakthrough eruption with only slight amounts of cooling (less than 1 °C per year) during the intervening 36 years
Обвал на действующем вулкане Желтовский (Южная Камчатка)
No full textВ статье описан крупный обвал, произошедший на вулкане Желтовский летом 2012 г. Показаны основные особенности вулканической постройки, получены главные морфометрические характеристики обвала. Обвалу, скорее всего, способствовало наличие большого количества слабосвязанных измененных пород в вершинной части вулканической постройки и переувлажнение грунтов в период снеготаяния. Никаких значимых сейсмических или метеорологических событий непосредственно перед обвалом не зафиксировано. Этот пример показывает, что крупные обвалы на вулканических постройках могут происходить без предвестников, что заставляет более внимательно подходить к проблеме оценки связанной с ними опасности. Статья полностью построена на данных дистанционных методов, большая часть которых была получена из общедоступных источников в сети Интернет
Опыт создания оперативной службы сбора данных сети наземных станций глобальных навигационных спутниковых систем
No full textПредставлен опыт создания программно-аппаратного комплекса сбора данных наземных станций глобальных спутниковых навигационных систем (ГНСС). Основа функционирования комплекса – специально разработанный формат представления данных и его реализации для реляционной базы данных. Описана процедура автоматической генерации кода программных библиотек, SQL-структур непосредственно из электронной документации приемника. Полученные решения были использованы в службе мониторинга ионосферы на базе сети ГНСС-станций Института прикладной геофизики им. Е.К. Федорова (Росгидромет)
Исследование радиоактивных загрязнений в природных средах на примере территории Челябинской области
No full textВ статье представлены результаты гамма-спектрометрических исследований загрязненности радионуклидом цезием-137 пойм и донных отложений озер Челябинской области. Выделены озера с максимальной величиной изотопа цезия-137