Bezymianny is one of the most active volcanoes in Kamchatka and the world. Its previous eruption occurred on October 18, 2023. Thermal activity of the volcano is shown, a description of the explosive eruption of July 24, 2024, and preceding events is given based on the study of video materials, as well as various satellite data from the information system “Remote Monitoring of the Activity of the Volcanoes of the Kamchatka and the Kuriles” (VolSatView, http://kamchatka.volcanoes.smislab.ru). The explosions were followed by the formation of pyroclastic flows in the Vostochnaya Valley, above which a coignimbrite cloud formed. An animated image of the movement of ash clouds from the volcano made from a series of Himawari-9 images in VolSatView (http://kamchatka.volcanoes. smislab.ru/animation/1721855961.webm) shows a rapid movement of the eruptive cloud to the southeast from the volcano and a slow movement of the long coignimbrite cloud to the southwest from the volcano. The eruptive cloud was noted in satellite images until 12:00 UTC on July 25, for about 2500 km from the volcano in the eastern part of the Pacific Ocean. The coignimbrite cloud slowly moved in a strip from the volcano along the Eastern Ridge of Kamchatka and then moved southwest along the eastern part of the Kuril Islands. This cloud was noted until 17:00 UTC on July 27, for about 1800 km from the volcano. Ash clouds were dangerous for international aviation: according to a representative of the Federal Air Transport Agency, 307 airliners used alternate routes on July 25. The main area of the territory where ash falls were observed, as of July 27, 2024, was about 462 thousand km2, including about 105 thousand km2 on land.

В работе описана активность вулканов Камчатки и Курил в 2023 г. Эксплозивные извержения вулканов Шивелуч, Ключевской и Безымянный представляли опасность для международных и местных авиаперевозок, Эбеко и Чикурачки − для местных авиаперевозок.

В работе представлены первые данные по составу ювенильных продуктов, изверженных вулканом Шивелуч в апреле 2023 г. Выполнено сравнение химического и минерального составов ювенильных андезитов и мафических включений, ассоциирующих с ними, с аналогичными данными для продуктов предшествующих крупных извержений.

Для определения источников тефры в ледовом керне, полученном в 2022 г. при бурении ледника
в кратере вулкана Ушковский на Камчатке, использован анализ химического состава вулканического
стекла в пепловых частицах. Сравнение полученных данных с опубликованными данными по составу
стёкол тефры современных извержений вулканов Камчатки позволило определить принадлежность
каждого горизонта тефры к конкретному вулкану-источнику.

В разрезах почвенно-пирокластических отложений впервые обнаружены горизонты шлаков, связанные с эксплозивными извержениями вулкана Кроноцкий, что подтверждает его статус действующего вулкана. Возраст извержений – ~5200-5400 л.н. и ~6000 л.н. – определен на основе стратиграфических соотношений горизонтов шлаков с ранее датированными маркирующими горизонтами тефры.

The paper presents summary data on the historical activity of Ivan Grozny volcano (Iturup Island, Kuril Islands), including the results of our own studies of solfatar-hydrothermal and eruptive activity of the volcano since 2004. Using modern analytical methods, we obtained data on the chemical composition of the volcano rocks and pyroclastics of the explosive eruption in 2012–2013. The composition of the volcano rocks varies from andesites to daciandesites of medium potassium series. Pyroclastics of the 2012–2013 eruption corresponds to andesites with medium potassium content in terms of bulk chemical composition. The material composition of glasses according to microprobe data is much more acidic. The obtained values are similar to the geochemical compositions of the products of the 1973 and 1989 eruptions. Taking into account the prevailing wind regime dominating in the central part of Iturup Island, the hazard from ash fall of probable future eruptions of Ivan Grozny volcano was assessed, indicating the predominant spread of ash in the north-western, western and south-western directions.

This article provides a brief description of the expedition work conducted by the staff of the Institute of Volcanology and Seismology, FEBRAS, in the central part of the Eastern Volcanic belt of Kamchatka, and in the Kamchatka River valley in the Summer-Autumn of 2023. In order to study the conditions for the formation and discharge of thermal waters of large volcanic centers, to estimate the hydrothermal discharge of magmatic volatiles (primarily CO2), hydrochemical and gas testing was carried out on the thermal fields of the Kikhpinych and Bolshoi Semyachik volcanic massifs, and in the Uzon caldera. In parallel with geochemical sampling, aerial and infrared photography of thermal sites was carried out. To determine the degree of influence of volcanic and hydrothermal activity on the ion runoff into the Pacific Ocean, hydrochemical and hydrological works were carried out in the Kamchatka Riverv alley. A comprehensive study of unique alkaline cold springs was carried out in the Belaya River valley (Kamchatsky Peninsula). A large number of water and gas samples, sediments and mineral salts were collected for further analytical studies during the expedition works.

В работе приведена информация о минеральных парагенезисах, сформировавшихся в двух различных поствулканических обстановках: на поверхности термального поля и вокруг бескорневых сольфатар пирокластического потока.