Report on Veniaminof (United States) — 22 March-28 March 2006
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 22 March-28 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, 22 March-28 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)
Web-camera images of Veniaminof on 24 March showed a steam-and-ash plume drifting from the summit cone at a height less than 2.3 km (7,600 ft) a.s.l. This level of activity was similar to activity on 23 March, but higher than activity on 21 and 22 March when a very diffuse steam-and-ash plume was confined to the summit caldera. The flow of seismic data from Veniaminof stopped on the evening of 21 March due to technical problems. The Concern Color Code remained at Yellow.
Geologic Background. Veniaminof, on the Alaska Peninsula, is truncated by a steep-walled, 8 x 11 km, glacier-filled caldera that formed around 3,700 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.