Report on Sheveluch (Russia) — 18 January-24 January 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 18 January-24 January 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Sheveluch (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 18 January-24 January 2012. Smithsonian Institution and US Geological Survey.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
KVERT reported that low levels of seismic activity were detected at Shiveluch during 13-20 January, and on 14 January ash plumes were observed. Satellite imagery showed a thermal anomaly over the lava dome every day except on 16 January. Ground-based observers noted that a viscous lava flow continued to effuse in the crater that was formed during a 2010 eruption and hot avalanches from the lava flow were occasionally observed at night with a web camera. Moderate fumarolic activity at the lava dome was observed during 13-14 and 17-18 January. The Aviation Color Code remained at Orange.
Based on satellite observations, the Tokyo VAAC reported that on 22 January a possible eruption produced a plume that rose to an altitude of 4.6 km (15,000 ft) a.s.l. and drifted NW; subsequent satellite images showed that ash was present. Based on information from satellite images and KVERT, ash plumes rose to an altitude of 5.2 km (17,000 ft) a.s.l. on 23 January and dissipated the next day.
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.