The work is devoted to the activity analysis of Kamchatka and the Kuril Islands volcanoes in 2019-2020.The activity of the volcanoes was estimated based on the processing of data from daily satellite monitoring carried out using the information system “Remote monitoring of Kamchatkan and the Kuriles volcanoes activity (VolSatView)”. The activity of the Kamchatka and the Kuril Islands volcanoes considered based on the analysis of their thermal anomalies. Analysis of the characteristics of thermal anomalies over volcanoes was carried out in KVERT IS. Analysis of the temperature of thermal anomalies of volcanoes in the Kuril - Kamchatka region in 2019-2020 shows a significantly higher activity of the Kamchatka volcanoes in comparison with the Kuril volcanoes.

The powerful explosive eruptions with large volumes of volcanic ash pose a great danger to the population and jet aircraft. Global experience in monitoring volcanoes and observing changes in the parameters of their thermal anomalies is successfully used to analyze the activity of volcanoes and predict their danger to the population. The Kamchatka Peninsula in Russia, with its 30 active volcanoes, is one of the most volcanically active regions in the world. The article considers the thermal activity in 2015–2022 of the Klyuchevskoy, Sheveluch, Bezymianny, and Karymsky volcanoes, whose rock composition varies from basaltic andesite to dacite. This study is based on the analysis of the Value of Temperature Difference between the thermal Anomaly and the Background (the VTDAB), obtained by manual processing of the AVHRR, MODIS, VIIRS, and MSU-MR satellite data in the VolSatView information system. Based on the VTDAB data, the following “background activity of the volcanoes” was determined: 20 °C for Sheveluch and Bezymianny, 12 °C for Klyuchevskoy, and 13–15 °C for Karymsky. This study showed that the highest temperature of the thermal anomaly corresponds to the juvenile magmatic material that arrived on the earth’s surface. The highest VTDAB is different for each volcano; it depends on the composition of the eruptive products produced by the volcano and on the character of an eruption. A joint analysis of the dynamics of the eruption of each volcano and changes in its thermal activity made it possible to determine the range of the VTDAB for different phases of a volcanic eruption.

Large explosive eruptions of volcanoes pose the highest hazard to modern jet f lights, because such eruptions can eject as much as several cubic kilometers of volcanic ash and aerosol into the atmosphere during a few hours or days. The year 2016 saw eruptions on 5 of the 30 active Kamchatka volcanoes (Sheveluch, Klyuchevskoy, Bezymianny, Karymsky, and Zhupanovsky) and on 3 of the 6 active volcanoes that exist on the North Kuril Islands (Alaid, Ebeko, and Chikurachki). Effusive activity was observed on Sheveluch, Klyuchevskoy, Bezymianny, and Alaid. All volcanoes showed explosive activity. The large explosive events mostly occurred from September through December (Sheveluch), a moderate ash emission accompanied the entire Klyuchevskoy eruption in March–November, and explosive activity of Karymsky, Zhupanovsky, Alaid, and Chikurachki was mostly observed in the earlie r half of the year. The ash ejected in 2016 covered a total area of 600 000 km2, with 460 000 km2 of this being due to Kamchatka volcanoes and 140 000 km2 to the eruptions of the North Kuril volcanoes. The activity of Sheveluch, Klyuchevskoy, and Zhupanovsky was dangerous to international and local f lights, because the explosions sent ash to heights of 10–12 km above sea level, while the eruptions of Bezymianny, Karymsky, Alaid, Ebeko, and Chikurachki were dangerous for local flights, since the ash did not rise higher than 5 km above sea level.

In 2024, explosive eruptions of the Sheveluch, Klyuchevskoy, Bezymianny, and Karymsky volcanoes occurred at Kamchatka, and the Ebeko volcano at the Northern Kurile Islands. On April 26, 2024, a new lava dome, named after the 300 years of the Russian Academy of Sciences began to grow in the area of the Karan old dome on the Stary Sheveluch volcano western slope. Powerful explosive eruptions that destroyed the new dome were observed on August 17–18, September 1–2, and November 7–10, 2024: eruptive columns rose up to 11 km above sea level, ash plumes extended for 2400 km mainly to the northeast and east of the volcano. The summit explosive eruption of the Klyuchevskoy volcano lasted from December 27, 2023 to January 2, 2024: explosions send ash up to 7 km above sea level and ash plumes extended for 230 km to the northwest of the volcano. The paroxysmal explosive eruption of Bezymianny volcano occurred on July 24, 2024: the eruptive cloud rose up to 12 km above sea level, the eruptive and coignimbrite clouds moved, respectively, to the northeast and northwest up to 2500 km from the volcano. The Bezymianny eruption forecast, which was published on the KVERT website, was realized 39 h 40 min later. Explosive activity of the Karymsky volcano was observed from June 20 to November 12, 2024: explosions raised ash up to 6 km above sea level and ash clouds moved for 665 km, mainly to the east and northeast of the volcano. In 2024, 287 explosive events occurred on the Ebeko volcano with ash removal up to 4.5 km above sea level. During the explosive eruptions, the Sheveluch and Bezymianny volcanoes were dangerous for international and local air travel and the Klyuchevskoy, Karymsky, and Ebeko volcanoes were dangerous for local air travel.