Report on Shishaldin (United States) — January 1996
Bulletin of the Global Volcanism Network, vol. 21, no. 1 (January 1996)
Managing Editor: Richard Wunderman.
Shishaldin (United States) Steam plumes; thermal anomaly on satellite images
Please cite this report as:
Global Volcanism Program, 1996. Report on Shishaldin (United States) (Wunderman, R., ed.). Bulletin of the Global Volcanism Network, 21:1. Smithsonian Institution. https://doi.org/10.5479/si.GVP.BGVN199601-311360.
54.756°N, 163.97°W; summit elev. 2857 m
All times are local (unless otherwise noted)
An eruption on 23 December was first reported by pilots who observed an ash plume as high as 10.5 km altitude (BGVN 20:11/12). Possible very light ashfall was reported a few hours later 90 km away. Large steam plumes were reported in early January, and an intermittent "hot spot" was detected on AVHRR satellite imagery during 5-26 January, in the vicinity of the summit crater. This thermal anomaly may reflect unusually high temperatures in the vicinity of the continuously active fumaroles in the summit crater. AVO received no additional pilot reports or other observations of eruptive activity after 26 January.
Geologic Background. The beautifully symmetrical Shishaldin is the highest and one of the most active volcanoes of the Aleutian Islands. The 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 steam plume often rises from its small summit crater. Constructed atop an older glacially dissected volcano, 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.
Information Contacts: Alaska Volcano Observatory.