Report on Veniaminof (United States) — 1 March-7 March 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 1 March-7 March 2006
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2006. Report on Veniaminof (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 1 March-7 March 2006. Smithsonian Institution and US Geological Survey.
56.17°N, 159.38°W; summit elev. 2507 m
All times are local (unless otherwise noted)
The Concern Color Code at Veniaminof was increased from Green to Yellow on 3 March. That morning ash emissions rose a few hundred meters above the intracaldera cone, drifted E, and dissipated rapidly. Ashfall was expected to be minor and confined to the summit caldera. Seismicity was low and did not indicate that a significantly larger eruption was imminent. AVO expected that steam-and-ash emissions may continue intermittently for days to weeks and could pose a hazard to people and low-flying aircraft in the vicinity of the active cone.
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 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.