Based on visual observations and analyses of satellite data, KVERT reported that during 19-26 July a viscous lava flow effused on the N flank of Shiveluch's lava dome, accompanied by hot avalanches, incandescence, and fumarolic activity. Satellite images detected a daily thermal anomaly. Based on analyses of satellite images, the Tokyo VAAC reported a possible eruption on 27 July. Ash was detected in images the next day. The VAAC also noted that, according to the Kamchatka Branch of Geophysical Services (KBGS; Russian Academy of Sciences), ash plumes rose to altitudes of 6.1-6.4 km (20,000-21,000 ft) a.s.l. on 27 and 29 July. KVERT reported that at 1317 on 29 July an explosion was observed by a web camera. An ash cloud detected in satellite images rose to an altitude of 3.5 km (11,500 ft) a.s.l. and drifted 60 km ESE; the cloud was 15 km long and 7 km wide. 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.

Sources: Kamchatkan Volcanic Eruption Response Team (KVERT), Tokyo Volcanic Ash Advisory Center (VAAC)