KVERT reported strong seismic activity at Shiveluch during 21-23 October and indicated that possible ash plumes rose to altitudes of 7.1-10.6 km (23,300-34,800 ft) a.s.l. Technical reasons prevented seismic data collection during 24-28 October. Ground-based observers noted hot avalanches in the lava dome area during 23-26 October; cloud cover prevented observations on the other days. Satellite imagery showed a large daily thermal anomaly over the lava dome and gas-and-steam plumes that drifted 170 km SE on 24 and 25 October. The Aviation Color Code remained at Orange.

Based on information from Yelizovo Airport (UHPP), the Tokyo VAAC reported that on 31 October an ash plume rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted E.

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: Tokyo Volcanic Ash Advisory Center (VAAC), Kamchatkan Volcanic Eruption Response Team (KVERT)