Report on Veniaminof (United States) — 11 September-17 September 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 11 September-17 September 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Veniaminof (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 11 September-17 September 2013. Smithsonian Institution and US Geological Survey.
56.17°N, 159.38°W; summit elev. 2507 m
All times are local (unless otherwise noted)
AVO reported continuous seismic tremor at Veniaminof during 11-17 September, and elevated surface temperatures detected in satellite images that were consistent with lava effusion and fountaining. On 11 September a diffuse steam plume possibly containing ash was recorded by the web cam in Perryville, 32 km SSE. Weak thermal anomalies and decreased levels of tremor during 14-16 September possibly indicated ongoing but diminished lava effusion. No unusual or eruptive activity was observed in web cam images through 17 September. The Volcano Alert Level remained at Watch and the Aviation Color code remained at Orange.
Geologic Background. Massive Veniaminof volcano, one of the highest and largest volcanoes on the Alaska Peninsula, is truncated by a steep-walled, 8 x 11 km, glacier-filled caldera that formed around 3700 years ago. The caldera rim is up to 520 m high on the north, is deeply notched on the west by Cone Glacier, and is covered by an ice sheet on the south. Post-caldera vents are located along a NW-SE zone bisecting the caldera that extends 55 km from near the Bering Sea coast, across the caldera, and down the Pacific flank. Historical eruptions probably all originated from the westernmost and most prominent of two intra-caldera cones, which reaches an elevation of 2156 m and rises about 300 m above the surrounding icefield. The other cone is larger, and has a summit crater or caldera that may reach 2.5 km in diameter, but is more subdued and barely rises above the glacier surface.