Based on visual observations and analyses of satellite data, KVERT reported that during 21-28 June a viscous lava flow effused on the N flank of Shiveluch's lava dome, accompanied by hot avalanches, incandescence, and fumarolic activity.

The seismic network detected a strong explosive eruption that occurred on 27 June from 0710 to 0800. The Aviation Color Code was raised to Red. Ash plumes drifted SE and SW, likely at altitudes of 10-12 km (33,000-39,400 ft) a.s.l. About 2 mm of red ash fell in Klyuchi Village, 50 km SW; ashfall was also reported in Lazo Village. Later that day the Alert Level was lowered back to Orange. Two ash explosions that occurred on 28 June at 0506 and 1001 produced ash plumes that rose to altitudes of 7 and 6 km (23,000 and 19,700 ft) a.s.l., respectively.

Based on analyses of satellite imagery, notices from Yelizovo Airport (UHPP), and the Kamchatka Branch of Geophysical Services (KBGS; Russian Academy of Sciences), the Tokyo VAAC reported that during 29-30 June an ash plume rose to an altitude of 5.5-6.4 km (18,000-21,000 ft) a.s.l. and drifted E and SE.

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)