Report on Sheveluch (Russia) — June 1993
Bulletin of the Global Volcanism Network, vol. 18, no. 6 (June 1993)
Managing Editor: Edward Venzke.
Sheveluch (Russia) Persistent gas-and-steam column with occasional ash; dome growth continues
Please cite this report as:
Global Volcanism Program, 1993. Report on Sheveluch (Russia) (Venzke, E., ed.). Bulletin of the Global Volcanism Network, 18:6. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199306-300270.
56.653°N, 161.36°E; summit elev. 3283 m
All times are local (unless otherwise noted)
The gas-and-steam column rising 1-6 km above the crater rim has persisted through 15 July . . . . A small amount of ash was occasionally present in the plume, which usually extended 30-40 km downwind. After decreasing in early June, seismicity increased again after 10 June. Seismic activity remained above background level 17-24 June, with at least 30 shallow earthquakes detected every day beneath the extrusive dome. On 29 June, rockfalls were observed on the growing dome at intervals of 3 minutes. Seven gas-and-steam bursts within one hour on 5 July produced a column up to 5 km high that extended >60 km S. Seismicity increased by a factor of 4.5 from 29 June to 5 July. Volcanic tremor was slightly above background on the night of 9 July. On 14 July, explosion sounds were heard in Kliuchi, 8 km S, but weather conditions prevented observations. The increase in seismic activity had only been detected by local stations as of 14 July. There were 42 seismic events recorded on 13 July, and 57 on 14 July by stations as far as 8 km from the volcano.
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.
Information Contacts: V. Kirianov and S. Zharinov, IVGG.