This paper describes the chemical composition of the thermal waters discharging on the northwestern slope of the active Ebeko Volcano in the Yuriev River valley. We are using continuous multiyear observations of the evolution of chemical and isotope compositions to estimate the response of volcanic events to the state of the hydrothermal system. It is shown that phreatomagmatic eruptions of the volcano were preceded by a change in the chemical and isotope compositions of thermal waters caused by increased inflow of magmatic volatiles into the system. The springs are observed to show increased concentrations of anion-generating components (chloride, sulfate, and fluorine ions) with concurrent increases in heavier isotopes of oxygen and hydrogen (deuterium) toward “andesitic” water. Recalling that the changes were detected a few months before the eruption, we infer that such geochemical effects can serve as predictive markers when monitoring the state of the volcano.

Unique compositional diversity of volcanic rocks was recently discovered in an active fault zone of the Sredinny Range (Kamchatka) located in the zone of monogenetic volcanism near the Tigil and Oxi volcanoes. The lavas in the zone represent common for SR medium-K, high-K and high-Ti, and also unique for Kamchatka high-LREE and high-Mg varieties. In this contribution, we present new Sr-Nd isotope data for a representative set of lava samples from this area. The isotopic and geochemical characteristics of the majority of selected samples can be explained by the differences in the amount of fluid, fluid sources and melting conditions, proposed earlier for the SR. The high-LREE picritic basalts, however, differ significantly from the other Kamchatka volcanic rocks—their highly unusual high-LREE, high-Li and low-LILE geochemical characteristics combine with the highest 87Sr/86Sr (0.70365) and second-highest εNd (9.9) values ever reported for lavas from the SR. We suggest that they represent the product of melting of the specific SR lithosphere domain that has been metasomatized by melts derived from a strongly degassed slab.

В августе 2024 г. были проведены комплексные научные исследования в районе вулкана Карымский, Камчатка. По данным инструментальных наблюдений показано, что в период межэруптивного внешне спокойного состояния вулкан продолжает интенсивную деятельность, выраженную в сейсмических событиях и интенсивной дегазации.

On the basе of general characteristics of large-scale volcanic collapses, it was concluded that the edifices of the Avachinsky and Koryaksky volcanoes are potentially ready for them. Possible scenarios of future collapses have been considered, which show that their debris avalanches can reach Petropavlovsk-Kamchatsky and Elizovo.

В работе дана сравнительная характеристика вершинных извержений вулкана Ключевской в 1935-2024 гг. и пароксизмальных фаз наиболее сильных эруптивных событий.

В работе описана активность вулканов Камчатки и Курил в 2024 г. Эксплозивные извержения вулканов Шивелуч, Ключевской и Безымянный представляли опасность для международных и местных авиаперевозок, Карымский и Эбеко − для местных авиаперевозок.