KVERT reported that moderate seismic activity was detected at Shiveluch during 28 January-4 February and many volcanic earthquakes were detected. A thermal anomaly over the lava dome was observed in satellite imagery. Gas and steam activity was occasionally observed. Ash plumes were seen rising to an altitude of 6 km (19,700 ft) a.s.l. on 30 January and 3 February. Ash plumes observed in satellite imagery drifted 120 km NE during 31 Janaury-1 February, and rose to altitudes of 6-8 km (19,700-26,200 ft) a.s.l. on 1 February. The Aviation Color Code remained at Orange.

The Tokyo VAAC reported that on 8 February a possible eruption detected in satellite imagery produced a plume that rose to an altitude of 4 km (13,000 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)