Report on Veniaminof (United States) — 28 November-4 December 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 28 November-4 December 2018
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2018. Report on Veniaminof (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 28 November-4 December 2018. 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 that the eruption of lava from the cone in Veniaminof’s ice-filled summit caldera continued during 27 November-3 December. Satellite and webcam data showed elevated surface temperatures. Steam and diffuse ash plumes were periodically identified in webcam and satellite images. During 27-28 November acoustic waves were recorded by regional infrasound sensors. Continuous low-amplitude tremor was recorded until the network went offline following a M 7 tectonic earthquake near Anchorage on 30 November. The Aviation Color Code remained at Orange (the second highest level on a four-color scale) and the Volcano Alert Level remained at Watch (the second highest level on a four-level scale).
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.