Sheveluch (also spelled Shiveluch) is a frequently active volcano consisting of Old Sheveluch and Young Sheveluch, with a large lava dome complex in the open crater that formed during a flank collapse in 1964 (figures 57 and 58). Typical activity consists of lava dome growth with intermittent ash emission and collapse events that produce block-and-ash flows. This report summarizes activity from November 2020 through June 2021 and is based on Kamchatka Volcanic Eruptions Response Team (KVERT) and Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences (IVS FEB RAS) reports and photographs, and satellite data. During this time activity consisted of lava dome growth, active fumaroles producing gas and steam, and visible incandescence of the eastern dome area when not obscured by clouds. Before this period, on 28 September 2020, a “whaleback” dome or lava spine was seen in the upper eastern part of the large dome that was given the name “Dolphin” by KVERT (BGVN 45:11). An image taken on 31 October showed the dome fracturing with new lava extrusion.

Figure 57. This view of Sheveluch from the SE shows Old Sheveluch to the right (NE) and Young Sheveluch to the left (SW). The active dome complex has formed within the 1964 flank collapse scarp. A gas plume is emanating from the dome and remobilized deposits within the Kabeku River channel are in the foreground. Base photo courtesy of the Kamchatka Volcanological Station.

Figure 58. This Google Earth terrain image shows some of the main features of Sheveluch as seen from the south. Two large block-and-ash flows E (2010) and W (2005) of the 1964 debris avalanche deposit formed as a result of collapse events from the active lava dome within the 1964 flank collapse scarp. The Kabeku River channel extends east from the 2010 deposit. Landsat/Copernicus satellite base image courtesy of Google Earth © Maxar Technologies.

Figure 59. The active lava dome at Sheveluch seen from the SW on 31 October 2020 with the rock fracturing due to new lava extrusion. The whaleback lava dome (center), at the top of the larger lava dome in the foreground, is brown with a smoother appearance in this photo and exhibits near-vertical fractures. Courtesy of Yu. Demyanchuk, IVS FEB RAS.

Frequent thermal anomalies were detected throughout November 2020-June 2021, with a decrease in energy output starting in November (figure 60). This was also seen in thermal satellite images when the active dome area was not obscured by clouds (figure 61). A gas-and-steam plume produced on the 30th dispersed 60 km NE. Avalanches of hot material from the growing dome area occurred through the month.

Figure 60. This MIROVA plot shows a relatively consistent output of thermal energy detected at Sheveluch from July 2020 through June 2021. There is a decrease of the average heat output starting in November 2020 and a slight increase in May 2021. Courtesy of MIROVA.

Figure 61. Sentinel-2 thermal infrared images acquired on 5 and 10 November 2020 show the active dome area in yellow to red, with the snow-covered summit and dome area in blue. The 10 November image shows the dome through light cloud cover. False color (urban, bands 12, 11, 4) renderings. Courtesy of Sentinel Hub Playground.

Low-level activity continued in early December, with avalanches of hot material from the dome removing a significant part of the whaleback by the 8th (figure 62). On the 22nd an explosion produced an ash plume up to 8 km altitude that dispersed E (figure 63), and a satellite image acquired the following day showed the ash deposit across the snow (figure 64). Another explosive event on the 24th again sent a plume to 8 km; both plumes reached around 625 km E. A satellite image acquired on 25 December showed fresh material across the dome and a lahar, likely from hot blocks melting snow (figure 65). Slightly lower ash plumes were erupted on the 29th, reaching 7 km altitude, with the latter plume drifting 250 km W.

Figure 62. The remnants of the “Dolphin” whaleback lava dome in the eastern part of the larger Sheveluch lava dome complex is shown in this 8 December 2020 photo. Courtesy of S. Chirkov, IVS FEB RAS.

Figure 63. An explosive eruption at Sheveluch on 22 December 2020 is seen in this image from the south. Image courtesy of IVS FEB RAS, KVERT.

Figure 64. A narrow ash deposit extending SE from Sheveluch from an explosion the previous day is visible across this 23 December 2020 Sentinel-2 satellite image. Sentinel-2 natural color (bands 4, 3, 2) rendering. Courtesy of Sentinel Hub Playground.

Figure 65. Fresh deposits emplaced on and around the Sheveluch lava dome after explosive activity, seen here on 25 December 2020. Sentinel-2 natural color (bands 4, 3, 2) rendering. Courtesy of Sentinel Hub Playground.

Continued dome growth produced hot avalanches, thermal anomalies, and gas-and-steam plumes (figures 66 to 70) during January through May, with no explosive activity reported. The whaleback dome continued to grow vertically, forming a smooth top similar to that seen in November. Ash resuspended by winds on 2 April created an ash plume that reached 2.5 km altitude and extended 400 km ESE.

Figure 66. These Sentinel-2 satellite images are natural color (large) and thermal infrared (inset) renderings of data collected on 4 January 2021 at Sheveluch. A steam-and-gas plume is rising from the active lava dome, with thermal output visible in the infrared image through the plume. Sentinel-2 natural color (bands 4, 3, 2) and false color (urban, bands 12, 11, 4) renderings. Courtesy of Sentinel Hub Playground.

Figure 67. This view of Sheveluch from the SW on 12 February 2021 shows the lava dome complex with the whaleback feature at the summit. Gas plumes rising from multiple locations across the dome are blowing to the left. Courtesy of the Kamchatka Volcanological Station.

Figure 68. This photo of Sheveluch from the SW on 21 March 2021 shows the growth of the smooth whaleback dome at the summit of the larger lava dome complex. A diffuse gas plume is visible in front of the Old Sheveluch scarp in the background. Courtesy of the Kamchatka Volcanological Station.

Figure 69. This photo shows the Sheveluch lava dome complex from the SW on 8 April 2021. The active whaleback dome is growing at the summit and gas rises from several locations. Courtesy of the Kamchatka Volcanological Station.

Figure 70. The Sheveluch lava dome is near the center of this webcam image, seen from the SW on 15 May 2021. The whaleback dome is the smooth vertical rock feature at the summit of the dome complex. Courtesy of IVS FEB RAS, KVERT.

Throughout June activity remained the same, with dome growth, avalanches, and gas emission (figure 71). By 16 June the whaleback dome was about 200 m high and 170 m wide at the base, and was beginning to crumble, producing avalanches (figures 72 and 73).

Figure 71. Sheveluch is seen here across the Kamchatka River from the SW on 16 June 2021. This view shows Old Sheveluch in the background and Young Sheveluch in the foreground. The whaleback dome (lower center) is extruding in the eastern summit area of the dome complex, from which gas plumes are also rising. Photos courtesy of the Kamchatka Volcanological Station.

Figure 72. These photos show the whaleback lava spine on the eastern summit of the large Sheveluch lava dome complex. The 15 June 2021 photo (top) shows gas emission from a vertical fracture. The 23 June images (bottom) show the area after a partial collapse of the spine along that fracture. All photos courtesy of the Kamchatka Volcanological Station.

Figure 73. The Sheveluch lava dome is shown here from above on 29 June 2021. Gas is rising from the dome and lighter streaks are avalanche deposits from the growth of the whaleback dome. The dome has partially filled the horseshoe-shaped 1964 collapse scarp that opens to the SW. The rim of the scarp is approximately 1.7 km wide in a NW-SE direction. PlanetScope satellite image courtesy of PlanetLabs.

Geological Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. The summit of roughly 65,000-year-old Stary Shiveluch is truncated by a broad 9-km-wide late-Pleistocene caldera breached to the south. Many lava domes occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. Widespread tephra layers from these eruptions have provided valuable time markers for dating volcanic events in Kamchatka. Frequent collapses of dome complexes, most recently in 1964, have produced debris avalanches whose deposits cover much of the floor of the breached caldera.

Information Contacts: Institute of Volcanology and Seismology, Far Eastern Branch, Russian Academy of Sciences (IVS FEB RAS), 9 Piip Blvd., Petropavlovsk-Kamchatsky 683006, Russia (URL: http://www.kscnet.ru/ivs/eng/); Kamchatka Volcanic Eruptions Response Team (KVERT), Far Eastern Branch, Russian Academy of Sciences, 9 Piip Blvd., Petropavlovsk-Kamchatsky, 683006, Russia (URL: http://www.kscnet.ru/ivs/kvert/); Kamchatka Volcanological Station, Klyuchi, Kamchatka Krai, Russia (URL: http://volkstat.ru/); MIROVA (Middle InfraRed Observation of Volcanic Activity), a collaborative project between the Universities of Turin and Florence (Italy) supported by the Centre for Volcanic Risk of the Italian Civil Protection Department (URL: http://www.mirovaweb.it/); Sentinel Hub Playground (URL: https://www.sentinel-hub.com/explore/sentinel-playground); Planet Labs, Inc. (URL: https://www.planet.com/).