Report on Sheveluch (Russia) — 27 November-3 December 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 27 November-3 December 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Sheveluch (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 27 November-3 December 2013. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
Based on visual observations and analyses of satellite data, KVERT reported that during 22-29 November a new lava dome extruded onto the NW part of Shiveluch's older lava dome. Moderate ash explosions generated ash plumes that rose to altitudes of 4-5 km (13,100-16,400) a.s.l. Lava-dome extrusion was accompanied by hot avalanches, incandescence, and fumarolic activity. A thermal anomaly was detected daily in satellite images. On 3 December activity increased and hot avalanches occurred continuously. Video data showed ash plumes rising to altitudes of 4-5 km (13,100-16,400) a.s.l. and drifting 20 km NW. A strong explosive event began at 1325 and generated ash plumes that rose to altitudes of 8-9 km (26,200-29,500 ft) a.s.l. and drifted NW. Pyroclastic flows descended the SW and NW flanks. The Aviation Color Code was raised to Red. Later that day KVERT noted that the strong explosive phase had ended; the Aviation Color Code was lowered back to Orange. An ash plume observed in satellite images was 200 km long and extended N. Ashfall was reported in Ivashka Village.
Geologic Background. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1300 km3 volcano is one of Kamchatka's largest and most active volcanic structures. 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 dot its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large horseshoe-shaped caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. At least 60 large eruptions have occurred during the Holocene, making it the most vigorous andesitic volcano of the Kuril-Kamchatka arc. 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.