Based on the processing of data from daily satellite monitoring carried out using the information system "Remote monitoring of the activity of volcanoes in Kamchatka and the Kuril Islands (VolSatView)", an analysis of the 2021-2022 thermal activity of Kamchatka and the Kuril Islands volcanoes is presented.

Sheveluch volcano is the most active volcano in Kamchatka. The paroxysmal explosive eruption of the volcano that destroyed the lava dome in the volcanic crater continued on April 10–13, 2023. According to various satellite data, the height of the separate eruptive clouds probably exceeded 15 km a. s. l. A powerful cyclone, which dominated the entire Kamchatka Peninsula, pulled the eruptive cloud to the west, turned it to the south, stretched it to the north and directed it to the east from the volcano. The dynamics of the development of ash and aerosol clouds of this eruption is reflected in the animations made from a series of Himawari-9 satellite images in the VolSatView IS from 08:00 UTC (Coordinated Universal Time) on April 10 to 07:50 UTC on April 14 (http://d33.infospace.ru/jr_d33/materials/2023v20n2/283-291/1683110898.webm) and of the Arctica-M1 satellite from 16:00 to 21:30 UTC April 10 (http://d33.infospace.ru/jr_d33/materials/2023v20n2/283-291/1683821166.webm). It was noted that the eruptive column was not vertical: for example, at the initial moment of the eruption on April 10 at 13:20 UTC, it deviated to the north-northeast, on April 11 at 12:00 UTC to the northwest, and on April 12 at 07:00 UTC to the southwest. During the paroxysmal eruption, sulfur dioxide continuously entered the atmosphere, the maximum amount of which was released on April 10–11, as a result of the explosive destruction of the lava dome of the Sheveluch volcano. Ash clouds along with aerosol clouds on April 10–13 were stretched into a strip more than 3500 km long from west to northeast. On April 21–22, the Sheveluch aerosol cloud was observed in the region of the Scandinavian Peninsula. The total area of the territory of Kamchatka and the Pacific Ocean where ash and aerosol plumes and clouds were observed during the April 10–13 eruption was about 3280 thousand km2. The paroxysmal eruption of Sheveluch volcano belongs to the sub-Plinian type because it is characterized by a big height of eruptive cloud and a long event duration. For this eruption, the VEI (Volcanic Explosivity Index) is estimated to be 3–4. A detailed description of the paroxysmal explosive eruption of Sheveluch volcano and the spread of the eruptive cloud was performed based on data from various satellite systems (Himawari-9, NOAA-18/19, GOES-18, Terra, Aqua, JPSS-1, Suomi NPP, Arctica-M1 etc.) in the information system “Remote monitoring of the activity of the volcanoes of the Kamchatka and the Kuriles” (VolSatView, http://kamchatka.volcanoes.smislab.ru).

В работе описана активность вулкана Безымянный в 2022 г. Произошло три пароксизмальных эксплозивных извержения вулкана в марте, мае и октябре, они представляли опасность для международных и местных авиаперевозок.

The 2020–2022 field works gave results that were used as a basis for describing the geological structure and whole-rock compositions for Kronotsky Volcano, one of the least known eruption centers in the East Volcanic Belt (EVB), Kamchatka. The stratovolcano edifice was estimated to be 350 km3 in volume, which is much above the respective figures for the other stratovolcanoes in the EVB frontal zone. The rocks are low-K and high-Fe tholeiitic basalts and basaltic andesites (SiO2 = 47.04‒53.15 wt %; K2O = 0.24‒0.65 wt %; FeO*/MgO = 1.2‒2.89). The basalts have extremely low concentrations of silica, potassium, titanium, and phosphorus compared with the rocks of the other frontal volcanoes in Kamchatka. The petrochemical differences thus identified were used to more accurately classify structures situated at the junction between the nearby Kronotsky and Krasheninnikov volcanoes. The acquired data will make the basis for further petrologic and geo-
chemical characterization of the volcano, as well as being possibly used for reconstructing the sequence of volcanic events in the area of study, including a more accurate history of the formation of Lake Kronotsky.

Data are presented on a moderate effusive-explosive eruption of the summit crater of Alaid volcano (Atlasov Island, Northern Kuril Islands) observed from September 10 to December 1, 2022. Based on satellite and visual data, it was found that as a result of Strombolian-Volcan activity two lava flows, 2.6 and 1 km long, were poured out on the southern slope of the volcano, and at least 16 emissions occurred to a height of 2.5 to 6 km a.s.l. The ash plumes spread out mainly in the southeast and east-southeast directions, their maximum length reaching 300–500 km. The eruption posed a danger to local airlines. The lava outpouring provoked the formation of lahars that descended the southern slope of the volcano and reached the island coast. The alluvial fan formed from mudflow masses partially deposited beyound the coastline, causing an increase in the island land.

Lake Kipyashchee (Boiling) with an area of ~4.6 ha and a maximum depth of 25 m fills the explosion funnel near one of the extrusive domes of the Golovnin volcano caldera. The water of the lake is ultra-acid (рН = 2.2–2.5) of the chloride-sulfate type with a mineralization of 2.0–2.2 g/l. The water temperature on the surface varies from 30 to 100°C, the average is 37°C. The flow of the lake is carried out through the Protoka in the lake Goryachee (Hot) is 120 l/s (August 2021). The hydrothermal output of magmatic Cl and S (as SO4) from Lake Kipyashchee is 10 t/day and 5.4 t/day, respectively. For the first time, the total diffusive removal of carbon dioxide from the surface of Lake Kipyashchee was estimated as 5.4 tons/day. Obtained from the results of field work in 2020–2021 geochemical data indicate an increase (compared to 2015) in hydrothermal activity in the Golovnin volcano caldera.

Based on computer vision and machine learning methods, algorithms have been developed to classify images from fixed video cameras, as well as detect signs of volcanic activity in them. The results of testing the developed algorithms are presented using the example of observation data on the Klyuchevskoy and Sheveluch volcanoes. It is shown that the proposed solutions can be used for operational and retrospective monitoring of volcanic activity.

This 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.