KVERT reported that during 19-29 March seismic activity from Shiveluch was above background levels, possibly indicating ash plumes rising to an altitude of 4.2 km (13,800 ft) a.s.l. Hot avalanches from the lava dome were seen at night. On 22 March, seismic signals detected an explosion that may have produced an ash plume rising to an altitude of 7 km (23,000 ft) a.s.l. Satellite imagery revealed a large daily thermal anomaly from the volcano, and ash plumes that drifted over 40 km NE on 21 March. The Aviation Color Code level remained at Orange.

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.

Source: Kamchatkan Volcanic Eruption Response Team (KVERT)