Report on Veniaminof (United States) — 14 November-20 November 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 November-20 November 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, 14 November-20 November 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 from the cone in Veniaminof’s ice-filled summit caldera, continued at low levels during 14-20 November. Satellite and webcam data showed elevated surface temperatures from minor lava spattering and lava effusion. Relatively continuous low-amplitude tremor was recorded. Steam and diffuse ash plumes were periodically identified in webcam and satellite images; plumes rose as high as 4.9 km (16,000 ft) a.s.l. on 16 November. Recent satellite data showed that the lava flows had traveled as far as 1.2 km from the vent. Fractures in the ice sheet adjacent to the lava flow continued to grow due to meltwater flowing beneath the ice sheet. 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.