The Kamchatkan Volcanic Eruption Response Team (KVERT) reported that during 24 October-6 November lava extrusion continued at Sheveluch’s “300 years of RAS” (Karan) dome on the SW flank of Old Sheveluch and at the dome at Young Sheveluch; activity escalated into an intense eruptive phase on 7 November. Thermal anomalies over both domes were identified in satellite images on 25, 27-28, and 31 October and 1-3 November, and over the “300 years of RAS” dome during 3-6 November. Weather conditions sometimes prevented views of the volcano.

According to the Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS) incandescence on the W side of the “300 years of RAS” dome was visible during 0800-0909 on 7 November. A strong explosive eruption began at 1919 and the entire volcanic complex was incandescent; pyroclastic material was likely ejected from both domes covered the dome complex. At 0920 incandescent pyroclastic flows descended the W flank of “300 years of RAS” dome. At 0927 lightning flashes at 8 km (26,200 ft) a.s.l. illuminated an ash plume that was rising and drifting E. Residents in Klyuchi observed lightning in the plume and heard explosions, and according to a news article felt a shock wave. KVERT raised the Aviation Color Code to Red (the highest level on a four-color scale) at 1027, noting that a large ash cloud was visible in satellite images rising 10-11 km (32,800-36,100 ft) a.s.l. and drifting ENE. IVS FEB RAS reported that by 1030 the ash cloud had expanded to 40 x 60 km and drifted 5 km NE. Reports included strong incandescence at the domes, explosions, pyroclastic flow deposits on the W flank, and pyroclastic flows descending the S flank during 1136-1140. According to a news report pyroclastic flow deposits extended more than 10 km W. Intense incandescence was periodically observed during the dark hours (1200-1900). Ash plumes rose 7-12 km (23,000-39,400 ft) a.s.l. and drifted as far as 300 km E and NE, causing ashfall in Ust-Kamchatsk and Cape Africa during 1940-2300. KVERT lowered the Aviation Color Code to Orange noting that although lava extrusion continued, the very intense explosions were no longer being recorded.

Volcano Observatory Notices for Aviation (VONA) issued by KVERT at 2250 on 7 November and at 0028 on 8 November noted that continuing explosions were producing ash plumes rising as high as 8.5 km (27,900 ft) a.s.l. and drifting 120 km E. KVERT raised the Aviation Color Code to Red at 0043 on 8 November based on satellite data from 0010 indicating ash plumes as high as 11 km (36,100 ft) a.s.l.. According to IVS FEB RAS an ash plume was visible in satellite images drifting 290 km E at an altitude of 6 km (19,700 ft) a.s.l. Another ash cloud that was 200 x 50 km in extent was about 190 km from the volcano drifting NE at 6 km a.s.l. During 2120-2200 ash plumes rose to 4.2 km (13,800 ft) a.s.l. and drifted E. Ash at 6 km a.s.l. continued to drifted E. A 6-km-altitude ash cloud 55 x 25 km was 450 km SE of the summit and another cloud, at the same altitude and 325 x 330 km in size, was 460 km NE of the summit. KVERT lowered the Aviation Color Code to Orange at 2149 on 8 November. Ash plumes rose 3.5-4 km (11,500-13,100 ft) a.s.l. and drifted E; ash plumes from earlier eruptive events extended as far as 550 km E.

KVERT issued VONAs for ash emissions on 9 November. Ash plumes rose as high as 5 km (16,400 ft) a.s.l. and drifted E at 0430 and rose as high as 4 km a.s.l. and drifted E at 2120. According to IVS FEB RAS weather clouds often prevented views throughout the day and incandescence from the complex was periodically visible through the night. Satellite images showed ash clouds at far distances from the volcano in multiple directions, for example: 0920 one plume was at 10 km a.s.l., 170 x 300 km, about 1,000 km NNE of the summit, and a second plume was at 8-10 km a.s.l. located 790 km NNW; at 2100 an ash cloud at 10 km a.s.l, 110 x 30 km, about 1,030 km NE.

Ash plumes continued to be produced on 10 November. KVERT reported that at 0440 an ash plume rose as high as 4 km a.s.l. and drifted 430 km ESE. IVS FEB RAS noted that ash emissions rose 4-8 km a.s.l. and drifted NE based on video and satellite data, and notices from the Tokyo VAAC. Dates are based on UTC times; specific events are in local time where noted.

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.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Institute of Volcanology and Seismology (IVS) of the Far Eastern Branch of the Russian Academy of Sciences (FEB RAS), Interfax News