Report on Sheveluch (Russia) — 19 July-25 July 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
19 July-25 July 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, 19 July-25 July 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 that a thermal anomaly was identified daily during 14-21 July in satellite images over Sheveluch. Based on video and satellite data explosive activity lasting about 8 hours on 24 July generated ash plumes that rose 11.5-12 km (37,700-39,400 ft) a.s.l. and drifted almost 700 km NE. Strong pyroclastic flows were also observed. The Aviation Color Code was raised to Red (the highest level on a four-color scale). Later that day only steam-and-gas emissions with a small amount of ash were noted; the Aviation Color Code was reduced to Orange.
Geological Summary. 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.