Report on Veniaminof (United States) — 26 September-2 October 2018
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 26 September-2 October 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, 26 September-2 October 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 at Veniaminof continued during 26 September-2 October, as evidenced by nighttime incandescence recorded by the FAA web camera in Perryville (35 km S), elevated surface temperatures in thermal satellite data, and elevated tremor levels. A gas plume was occasionally visible during clear daytime conditions. On 26 September lava fountains, visible in webcam images, rose from a second vent located 75 m N of the vent producing lava flows. Minor ash emissions associated with lava fountaining possibly rose as high as km (15,000 ft) a.s.l. and quickly dispersed. The lava flow had traveled 1 km down the S flank of the summit cone by 1 October. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.
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.