KVERT reported that during 29 April-6 May a thermal anomaly on Shiveluch was detected in satellite imagery. According to ground-based observations during 28-29 April ash plumes rose to an altitude of 4.5 km (14,800 ft) a.s.l. On 1 May ash plumes observed in satellite imagery drifted 124 km NE. Seismic data indicated that possible ash plumes rose to an altitude of 6 km (19,700 ft) a.s.l. on 29 April and 2 May. KVERT noted that the Aviation Color Code remained at Orange. Based on analyses of satellite imagery, the Tokyo VAAC reported that on 7 May a possible eruption produced a plume that rose to an altitude of 5.2 km (17,000 ft) a.s.l. and drifted E. Subsequent notices that day stated that ash had dissipated.

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)