This paper examines the Karymsky Volcanic Center to estimate how much volcanic and hydrothermal activity affects the chemical composition of river water. We evaluate the volumes of major and trace elements coming to the Pacific Ocean via the Karymsky River. We assess the quality of river water in compliance with the regulations for potable water, water used for household work, and in fisheries. It is shown that the formation of ion load of the river water mostly occurs by inflow of thermal waters, as well as due to water-soluble complexes of ashes discharged by Karymsky Volcano and coming to the catchment area of the river. The annual volume of dissolved material transported by the river to the Kronotsky Bay of the Pacific Ocean amounts to more than 90 kilotons.

The 1991 eruption of Avacha volcano resulted in a lava plug inside its crater, making high-temperature fumaroles available for sampling. At present, there are two high-temperature fumarolic fields: the Eastern (up to 665 ◦ C) and the Western (up to 840 ◦ C), both associated with a fissure in the lava plug caused by a weak 2001 explosion. The paper presents chemical and isotopic compositions (H-O-C-S) of the directly sampled fumaroles over the period 2013 – 2023, mainly from the Eastern field. We revealed seasonal variations of water isotopic composition and concentrations of some components of the gas. High-temperature gases from Avacha volcano are characterized by chemical and isotopic compositions typical for volcanoes in subduction zones, but with a slightly increased content of H2O, a reduced content of HCl. A relatively high concentration of methane is noted in the gases of low-temperature field. Methane in high-temperature gas with δ13C(CH4) = 16.8 ‰ has abiogenic origin. For high-temperature gases, their redox state (H2/H2O and CO/CO2) is controlled mainly by the sulfur gas buffer (H2S/SO2); methane is not chemically equilibrated. The molar ratio C/S ~ 1 is typical for volcanoes in the Kuril-Kamchatka Arc. The measured fumarolic temperatures at the Eastern field are descending over time from 626 ◦ C in 2013 to 410 ◦ C in 2023. The apparent equilibrium temperatures calculated for reactions that include CO, CO2, H2, H2O, H2S and SO2 are generally higher than the measured temperatures and do not show the descending trend. However, calculated equilibrium temperatures for the H2O-CO-CO2-CH4 system are very close to the measured temperatures. Two periods of the increased seismic activity which occurred from 2013 to 2023, in November 2014 – January 2015 and October – December 2019, correlated with changes in the morphology and gas flow rates at the Western fumarolic field.

This paper considers the propagation of ash during the paroxysmal eruption of Sheveluch Volcano which occurred April 10–13, 2023, and its impact on the water resources of the affected area. We characterize ash thicknesses at various population centers and describe the grain-size composition of the ash. We show that the propagation of ash plumes is primarily driven by the eruption dynamics, but atmospheric circulation actually controls the spatial distribution of deposit thickness. The water-soluble salts contained in the ash and the dynamics of their washing out under natural conditions have been determined. The water-soluble part of fresh ash is dominated by calcium and magnesium sulfates, sodium chloride, with minor amounts of chlorides and fluorides of aluminum, potassium, and ammonium. The first substances to be washed out from ashes are well-soluble chlorides, to be followed by sulfates. As time goes on, the total concentration of soluble salts is decreasing, and their qualitative composition changes: hydrogen carbonates of calcium, magnesium, and sodium begin to dominate. Several months after the eruption, the impact of the ashfall on water resources of the settlements, including open springs at the ground surface, was leveled out.

Северная группа вулканов Камчатки – уникальна. Она является своеобразной “горячей точкой планеты”, здесь находятся одни из самых активных вулканов мира: Шивелуч, Ключевской и Безымянный. Каждый из вулканов обладает оригинальными магматической системой, составом эруптивных продуктов, особенностями развития. В то же время они иногда работают одновременно, а иногда откликаются на активность друг друга. Описанию их эруптивной деятельности с середины прошлого века до наших дней и посвящена монография.

Шивелуч — один из наиболее активных вулканов Камчатки. Его современная постройка включает три главных элемента: Старый Шивелуч, древнюю кальдеру и Молодой Шивелуч. На юго-западном склоне Старого Шивелуча находится группа древних экструзивных куполов (с юга на север): Шероховатая, Красная, Каран, Сопочка на склоне. Только в районе купола Каран имеются прогретые площадки с температурой мофет 70–96 °С. После мощного эксплозивного извержения влк. Шивелуч в апреле 2023 г. парогазовая активность купола Каран усилилась, на спутниковых снимках в районе купола начала отмечаться слабая термальная аномалия. На спутниковом снимке JPSS-12 (англ. Joint Polar Satellite System) от 6 апреля 2024 г. в 15:07 UTC (англ. Coordinated Universal Time) в районе купола Каран учёные KVERT (англ. Kamchatkan Volcanic Eruption Response Team) обнаружили яркую термальную аномалию, т. е. в этот день они зафиксировали уникальное явление: рождение нового вулканогенного образования — лавового купола, который назван «300 лет РАН». По состоянию на 7 июня 2024 г. размер нового купола составляет 800×500 м, площадь короны купола — 0,19 км2. Извержение купола «300 лет РАН» продолжается.

Исходя из анализа Величины Разницы Температур термальной Аномалии и Фона (ВРТАФ) в информационной системе VolSatView определен «фон активности» вулканов Шивелуч, Ключевской и Безымянный для периода 2015-2022 гг. Совместный анализ динамики извержения каждого вулкана и изменения его термальной активности позволил установить диапазон ВРТАФ для разных фаз извержения вулкана.