Based on visual observations and analyses of satellite data, KVERT reported that during 26 July-2 August a viscous lava flow effused on the NW flank of Shiveluch's lava dome, accompanied by hot avalanches, incandescence, and fumarolic activity. Satellite images detected a daily thermal anomaly.

A strong explosion at 2255 on 26 July generated ash plumes that rose as high as 10 km (23,800 ft) a.s.l. and drifted 520 km SE. Pyroclastic flows traveled 5 km. An ash cloud 15 x 7 km was observed in satellite images about 60 km SE of the volcano on 29 July. At 1707 on 4 August video images showed an ash plume rising to altitudes of 4.5-5 km (14,800-16,400 ft) a.s.l. and drifting 50 km E. The next day the seismic network detected an explosion at 1604; video images showed an ash plume rising to altitudes of 6.5-7 km (21,300-23,000 ft) a.s.l. and drifting 50 km ESE. The Aviation Color Code 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)