Report on Sheveluch (Russia) — 10 May-16 May 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 10 May-16 May 2017
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2017. Report on Sheveluch (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 10 May-16 May 2017. 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 continuing lava-dome extrusion at Sheveluch’s N flank during 5-11 May. A daily thermal anomaly over the dome was identified in satellite images, and ash plumes drifted 90 km NNE and NW on 8 and 10 May. Strong explosions on 12 May generated ash plumes identified in satellite images that rose 9-10 km (29,500-32,800 ft) a.s.l., spread 70 km wide, and drifted 115 km NW. The Aviation Color Code was raised to Red. A few hours later satellite images showed a thermal anomaly and no ash emissions; the Aviation Color Code was lowered to Orange. Explosions on 16 May generated ash plumes that rose 8-9 km (26,200-29,500 ft) a.s.l., prompting KVERT to again raise the Aviation Color Code to Red. Pyroclastic flows descended the flanks and produced ash plumes that rose 3.5-4 km (11,500-13,100 ft) a.s.l. and drifted NE. Within a few hours satellite images showed a thermal anomaly and no ash emissions; the Aviation Color Code was lowered to Orange. An ash cloud with the dimensions of 51 x 43 km was still visible in satellite images, moving E.
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.