Although frequently obscured by weather clouds, low-level fumarolic activity was noticed on 10 November. Seismicity at or near the active dome was above normal in early November (9-16 events/day), with weak tremor (18-36 minutes/day). Seismicity remained above normal on 11 November, with 8 events at the active dome between 10 November and noon the next day; continuous tremor for 2.6 hours was recorded before 1230. Weak fumarolic activity continued on the 12th with a gas-and-steam plume to 1 km above volcano being blown SE. During 12-18 November, 10 shallow earthquakes were recorded near the active dome; weak tremor (0.1 µm) lasted for ~54 minutes on 18th. Seismicity on the 23rd consisted of two shallow earthquakes beneath the active dome. On 24 November, ground observers noted fumarolic activity at the summit dome with a gas-and-steam plume rising 800 m. Weak volcanic tremor on 23 and 24 November had a duration of ~18 minutes each day with a maximum amplitude of 0.1 µm. Other earthquake activity remained slightly above normal. Slight fumarolic activity on 28 November from the summit dome was seen from Kliuchi; weak tremor and six shallow earthquakes were detected. The seismic station closed indefinitely as of December 7. The volcano was obscured by clouds 8-14 December, and no information was available for late December because of the suspension of communications from KVERT.

Geological Summary. The high, isolated massif of Sheveluch volcano (also spelled Shiveluch) rises above the lowlands NNE of the Kliuchevskaya volcano group. The 1,300 km3 andesitic volcano is one of Kamchatka's largest and most active volcanic structures, with at least 60 large eruptions during the Holocene. 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 occur on its outer flanks. The Molodoy Shiveluch lava dome complex was constructed during the Holocene within the large open caldera; Holocene lava dome extrusion also took place on the flanks of Stary Shiveluch. 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, IVGG; AVO.