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Report on Shishaldin (United States) — 29 January-4 February 2014

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 29 January-4 February 2014
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2014. Report on Shishaldin (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 29 January-4 February 2014. Smithsonian Institution and US Geological Survey.

Volcano Profile |  Weekly Report (29 January-4 February 2014)


Shishaldin

United States

54.756°N, 163.97°W; summit elev. 2857 m

All times are local (unless otherwise noted)


On 30 January, AVO raised the Aviation Color Code for Shishaldin to Yellow and the Volcano Alert Level to Advisory based on increased surface temperatures detected at the summit crater by satellite images over the previous few days, as well as increased steam emissions observed on 29 January in satellite and web-camera images. No steam emissions were observed during 30-31 January. Elevated surface temperatures were again detected on 1 February.

Geologic Background. The beautifully symmetrical volcano of Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The 2857-m-high, glacier-covered volcano is the westernmost of three large stratovolcanoes along an E-W line in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." A steady steam plume rises from its small summit crater. Constructed atop an older glacially dissected volcano, it is Holocene in age and largely basaltic in composition. Remnants of an older ancestral volcano are exposed on the west and NE sides at 1500-1800 m elevation. There are over two dozen pyroclastic cones on its NW flank, which is blanketed by massive aa lava flows. Frequent explosive activity, primarily consisting of strombolian ash eruptions from the small summit crater, but sometimes producing lava flows, has been recorded since the 18th century.

Source: US Geological Survey Alaska Volcano Observatory (AVO)