Report on Shishaldin (United States) — February 1979
Scientific Event Alert Network Bulletin, vol. 4, no. 2 (February 1979)
Managing Editor: David Squires.
Shishaldin (United States) Ash emission increases
Please cite this report as:
Global Volcanism Program, 1979. Report on Shishaldin (United States) (Squires, D., ed.). Scientific Event Alert Network Bulletin, 4:2. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN197902-311360
54.756°N, 163.97°W; summit elev. 2857 m
All times are local (unless otherwise noted)
Peninsula Airways pilots reported unusually strong ash emission during overflights on 14 or 15, and 27 February. Ashfall, usually confined to the summit area, was occurring on the upper half of the volcano.
Geological Summary. The symmetrical glacier-covered Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. It is the westernmost of three large stratovolcanoes in the eastern half of Unimak Island. The Aleuts named the volcano Sisquk, meaning "mountain which points the way when I am lost." Constructed atop an older glacially dissected edifice, it is largely basaltic in composition. Remnants of an older ancestral volcano are exposed on the W and NE sides at 1,500-1,800 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. A steam plume often rises from the summit crater.
Information Contacts: G. Morgan, Peninsula Airways.