Due to an increase in volcanic and seismic activity at Shiveluch, KVERT raised the Concern Color Code from Yellow ("volcano is restless") to Orange ("volcano is in eruption or eruption may occur at any time"). On 1 June at 1616 a short-lived explosive eruption produced an ash-and-gas plume to a height of 3 km above the lava dome. The plume was visible from Klyuchi town, 46 km from Shiveluch. Two ~3-minute-long shallow seismic events were recorded at 1615 and 1626. Prior to the eruption, on 31 May at 1530, a ML (local magnitude) 3.1 earthquake occurred. On 1 June continuous volcanic tremor occurred for about an hour. Small gas-and-steam plumes rose to 1.3 km above the dome. Thermal anomalies were visible on satellite imagery on 31 May and 1 June.

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)