According to observations and video data, KVERT reported fumarolic activity from Shiveluch during 2-4 and 6-7 December. Based on satellite imagery, the Tokyo VAAC reported possible eruption plumes on 8 and 11 December that reached altitudes of 5.2 km (17,000 ft) a.s.l. and drifted SW and NE, respectively. Satellite imagery and a pilot observation reported by the VAAC indicated ash plumes on 12 December to altitudes of 3-5.8 km (10,000-19,000 ft) a.s.l.

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), Tokyo Volcanic Ash Advisory Center (VAAC)