Annually, from 3 to 6 Kamchatkan volcanoes produce eruptions, during which the explosions eject ash to 10-15 km a.s.l., and ash clouds spread thousands of kilometers from volcanoes. Ash clouds pose a serious threat to the modern jet aviation. Scientists of KVERT have conduct daily monitoring of Kamchatka volcanoes since 1993, to mitigate volcanic hazards to airline operations and population. Since 2014, satellite monitoring of volcanoes they carried out with the VolSatView (Remote monitoring of active volcanoes of Kamchatka and the Kuril Islands) (http://volcanoes.smislab.ru) IS. The system utilize all the available satellite data, weather and video observations to ensure continues monitoring and study of volcanic activity in Kamchatka. The VolSatView work with distributed information resources and computation systems. This work was supported by the Russian Science Foundation, project No. 16-17-00042.

There are 30 active volcanoes in the Kamchatka, and several of them are continuously active. In the XX-XXI centuries 17 volcanoes of Kamchatka erupted. During this time, 183 volcanic eruptions occurred, including three catastrophic eruptions (Ksudach, 1907; Bezymianny, 1956; Sheveluch, 1964). Strong explosive eruptions of volcanoes were the most dangerous for human society because they produce in a few hours or days to the atmosphere till 2-3 cubic kilometers of volcanic products. Ash plumes and the clouds, depending on the power of the eruptions, the strength and wind speed, to traveled thousands of kilometers from the volcanoes for several days. Any territory of the Kamchatka Peninsula has repeatedly been exposed to ash falls, the thickness of ash in settlements was from less than 1 mm to 4-5 cm. Strong explosive eruptions of volcanoes Sheveluch, Klyuchevskoy, Bezymianny, Kizimen, Karymsky, Zhupanovsky, Avachinsky, Kambalny were the most dangerous for air travel not only over Kamchatka, but also hundreds of kilometers away from the peninsula.
The strong explosive and effusive eruptions of Sheveluch, Klyuchevskoy, Bezymianny, Kizimen and the other were often accompanied by the formation of hot mud flows (lahars), which sometimes disrupted transport communications (roads, bridges) of nearby settlements.
Scientists of KVERT monitor Kamchatkan volcanoes since 1993. Thanks to satellite monitoring of volcanoes carried out by KVERT, several explosive eruptions were predicted in the XXI century, and early warnings were made to the population about possible ashfalls in settlements and about hazard to aviation.

The active andesitic Zhupanovsky Volcano consists of four coalesced stratovolcano cones. The historical explosive eruptions of 1940, 1957, and 2014‒2016 discharged material from the Priemysh Cone. The recent Zhupanovsky eruptions were studied using satellite data supplied by the Monitoring of Active Volcanoes in Kamchatka and on the Kuril Islands information system (VolSatView), as well as based on video and visual observations of the volcano. The first eruption started on October 22 and lasted until October 24, 2013. Fumaroles situated on the Priemysh western slope were the centers that discharged gas plumes charged with some amount of ash. The next eruption started on June 6, 2014 and lasted until November 20, 2016. The explosive activity of Zhupanovsky was not uniform in 2014–2016, with the ash plumes being detected on satellite images for an approximate total duration of 112 days spread over 17 months. The most vigorous activity was observed between June and October, and in November 2014, with a bright thermal anomaly being nearly constantly seen on satellite images around Priemysh between January and April 2015 and in January–February 2016. The 2014–2016 eruption culminated in explosive events and collapse of parts of the Priemysh Cone on July 12 and 14, November 30, 2015, and on February 12 and November 20, 2016.

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.

There are 30 active volcanoes in the Kamchatka, and several of them are continuously active. In 2014-2015, four of the Kamchatkan volcanoes (Sheveluch, Klyuchevskoy, Karymsky and Zhupanovsky) had strong and moderate explosive eruptions.
Strong explosive eruption of volcanoes is the most dangerous for aircraft because in a few hours or days in the atmosphere and the stratosphere can produce about several cubic kilometers of volcanic ash and aerosols. Ash plumes and the clouds, depending on the power of the eruption, the strength and wind speed, can travel thousands of kilometers from the volcano for several days, remaining hazardous to aircraft, as the melting temperature of small particles of ash below the operating temperature of jet engines.
Annual Kamchatkan strong explosive eruptions with ash emissions by 8-15 km above sea level represent a real threat to modern jet aviation. To reduce the risk of aircraft encounters with volcanic ash clouds in the North Pacific region, since 2002, KVERT IVS FEB RAS conduct a daily satellite monitoring of 30 Kamchatkan volcanoes and visual and video monitoring of Klyuchevskoy, Sheveluch, Bezymianny, Koryaksky, Avachinsky, Mutnovsky and Gorely volcanoes. KVERT analyses seismic data for 9 volcanoes (Klyuchevskoy, Sheveluch, Bezymianny, Tolbachik, Kizimen, Karymsky, Koryaksky, Avachinsky and Gorely) from the Kamchatkan Branch of Geophysical Survey RAS.
KVERT send Volcano Observatory Notice for Aviation (VONA) by email to Airport Meteorological Center (AMC) at Yelizovo Airport; and the Tokyo Volcanic Ash Advisory Centers (VAAC), the Anchorage VAAC, the Washington VAAC, the Montreal VAAC, and the Darwin VAAC; aviation services, and scientists located throughout the North Pacific region. VONA/KVERT Releases are posted on the web site: http://www.kscnet.ru/ivs/kvert/
Since 2011, experts from IVS FEB RAS, Space Research Institute RAS, Computing Center FEB RAS and the Far Eastern Planeta Research Center have operated the information system “Monitoring of Volcanoes Activity in Kamchatka and the Kuriles” (VolSatView; http://volcanoes.smislab.ru) that uses all available satellite data (operative and long-term archive data), weather and on-ground observations, the results of computational modeling of ash clouds and plumes trajectories to ensure continues monitoring and study of volcanic activity in Kamchatka and the Kuriles.

This paper reconstructs, for the first time, the motion dynamics of an eruptive cloud formed during the catastrophic eruption of the Sheveluch volcano in November 1964 (Volcanic Explosivity Index 4+). This became possible due to the public availability of atmospheric reanalysis data from the ERA-40 archive of the European Center for Medium-Range Weather Forecasts (ECMWF) and the development of numerical modeling of volcanic ash cloud propagation. The simulation of the eruptive cloud motion process, which was carried out using the FALL3D and PUFF models, made it possible to clarify the sequence of events of this eruption (destruction of extrusive domes in the crater and the formation of an eruptive column and pyroclastic flows), which lasted only 1 h 12 min. During the eruption, the ash cloud consisted of two parts: the main eruptive cloud that rose up to 15,000 m above sea level (a.s.l.), and the co-ignimbrite cloud that formed above the moving pyroclastic flows. The ashfall in Ust-Kamchatsk (Kamchatka) first occurred out of the eruptive cloud moving at a higher speed, then out of the co-ignimbrite cloud. In Nikolskoye (Bering Island, Commander Islands), ash fell only out of the co-ignimbrite cloud. Under the turbulent diffusion, the forefront of the main eruptive cloud rose slowly in the atmosphere and reached 16,500 m a.s.l. by 04:07 UTC on November 12. Three days after the eruption began, the eruptive cloud stretched for 3000 km over the territories of the countries of Russia, Canada, the USA, Mexico, and over both the Bering Sea and the Pacific Ocean. It is assumed that the well-known long-term decrease in the solar radiation intensity in the northern latitudes from 1963–1966, which was established according to the world remote sensing data, was associated with the spread of aerosol clouds formed not only by the Agung volcano, but those formed during the 1964 Sheveluch volcano catastrophic eruption

In 2005, six major eruptions of four Kamchatka volcanoes (Bezymyannyi, Klyuchevskoy, Shiveluch, and Karymskii) occurred and the Avachinskii, Mutnovskii, and Gorelyi Kamchatka volcanoes and the Ebeko and Chikurachki volcanoes in northern Kurils were in a state of increased activity. Owing to a close collaboration between the KVERT project, Elizovo airport meteorological center, and volcanic ash advisory centers in Tokyo, Anchorage, and Washington (Tokyo, Anchorage, and Washington VAACs), all necessary measures for safe airplane flights near Kamchatka were taken and fatal accidents related to volcanic activity did not occur.