Volcano Update from Archive

The Alaska Volcano Observatory is lowering the Aviation Color Code to GREEN and the Alert Code to NORMAL at Shishaldin volcano.

Seismic levels at Shishaldin volcano have decreased to background levels and have been at this level since late December 2008. A very weak thermal anomaly was last detected on February 3, 2009. Reports of steam issuing from the summit crater continue to be received although this is not anomalous activity at this volcano; steaming is typical.


Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 10 miles (16 km). A small summit crater typically emits a noticeable steam plume with occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, erupting atleast 28 times since 1775. Most of Shishaldin's eruptions have consisted of small ash and steam plumes, although the most recent eruption in April-May 1999 produced an ash column that reached a height of 45,000 ft above sea level.no ash cloudslow-level steam plumes are normal at this volcano.no ash cloudslow-level steam plumes are normal at this volcano.