KVERT reported that seismic activity at Shiveluch was above background levels during 9-16 January. Based on interpretations of seismic data, ash plumes rose to altitudes of 7.3 km (23,900 ft) a.s.l. and 6.9 km (22,600 ft) a.s.l. on 9 and 14 January, respectively, and to an altitude of 5.5 km (18,000 ft) a.s.l. on the other days during the reporting period. Observers reported that ash plumes rose to an altitude of 3.5 km (11,500 ft) a.s.l. on 9 January and noted gas-and-steam activity during 8-10 and 12-14 January. Analysis of satellite imagery revealed a large daily thermal anomaly over the lava dome and gas-and-steam plumes that drifted about 70 km S, SE, and NE during 9-11 and 13 January. The Level of Concern Color Code remained at Orange.

Based on information from KEMSD, the Tokyo VAAC reported that on 18 January an eruption produced a plume that rose to an altitude of 5.8 km (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)