Report on Sheveluch (Russia) — 6 March-12 March 2019
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 6 March-12 March 2019
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2019. Report on Sheveluch (Russia). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 6 March-12 March 2019. 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 over Sheveluch’s lava dome was identified daily in satellite images during 1-8 March. Strong gas-and-steam emissions containing variable amounts of ash rose to altitudes of 3.5-4 km (11,500-13,100 ft) a.s.l. and drifted about 50 km E on 1 March. On 9 March explosions generated ash plumes that rose 10-11.2 km (32,800-36,700 ft) a.s.l. and drifted 70 km NW and N, prompting KVERT to raise the Aviation Color Code to Red (the highest level on a four-color scale). Early on 10 March the Aviation Color Code was lowered to Orange. Ash plumes continued to rise from the crater, to an altitude of 8 km (26,200 ft) a.s.l., and drift 375 km N. Later that day gas-and-steam plumes with some ash rose as high as 4.5 km (14,800 ft) a.s.l. and drifted 15 km NE. On 11 March an ash plume rose as high as 4.7 km (15,400 ft) a.s.l. and drifted 70 km SE.
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.