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.

Geological Summary. The symmetrical glacier-covered Shishaldin in the Aleutian Islands 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 edifice 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 covered 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: Alaska Volcano Observatory.