Based on visual observations and analyses of satellite data, KVERT reported that during 11-18 October a viscous lava flow effused onto the N and NE flanks of Shiveluch's lava dome, accompanied by hot avalanches, incandescence, ash explosions, and fumarolic activity. A thermal anomaly was detected daily in satellite images.

At 1528 on 18 October video data showed ash plumes rising to altitudes of 9-10 km (29,500-32,800 ft) a.s.l. Several explosions during 1506-1528 generated ash plumes that rose to an altitude of 10 km (32,800 ft) a.s.l. and drifted SE. The Aviation Color Code was raised to Red. Video images showed ash plumes rising to 6-7 km (19,700-23,000 ft) a.s.l. at 1634, to altitudes of 7-7.5 km (23,000-24,600 ft) a.s.l. at 1708 and 1722, and to altitudes of 9 km (29,500 ft) a.s.l. at 1753 and 1759. KVERT announced that the Aviation Color Code was lowered to Orange at 2038. Continuous ash emissions produced plumes that rose 3-3.5 km (9,800-11.500 ft) a.s.l. and drifted S. The lava dome continued to grow.

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)