Seismic activity was above background levels during 31 August-7 September. Spasmodic volcanic tremor and weak, shallow seismic signals (possible collapses and avalanches) were registered the entire week. Several gas-and-steam plumes were observed, with the highest rising 1.2 km above the dome. On 4 September an explosion produced an ash plume that rose 1 km above the dome and a 1-km-long pyroclastic flow that traveled to the SE. Thermal anomalies were visible on satellite imagery. The volcano remained at Concern Color Code 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)