Since an ash cloud was detected on 6 February 2006 (BGVN 31:01), observers have documented two brief spurts of activity. On the morning of 2 May beginning at 0101, a thermal anomaly and continuous plume were seen on satellite imagery. The plume extended ~ 50 km SW and was visible on imagery for ~ 6 hours. Satellite data suggested a maximum height of ~ 1 km altitude There was no indication of ash in the cloud. No further activity was detected for several weeks after the 2 May plume. In this interval Cleveland was not assigned a Concern Color Code because there is no real-time seismic network at the volcano.

The second episode took place on 23 May 2006. AVO reported that an astronaut aboard the International Space Station observed an ash plume from Cleveland at 1500. At 1507 satellite imagery showed a plume that drifted SW and reached an altitude of ~ 6.1 km. At 1700, an image showed the detached ash plume 130 km SW of Cleveland. The Concern Color Code was raised to Yellow.

The ash plume had mostly dissipated by 24 May. On 26 May, AVO downgraded the Concern Color Code from Yellow to "Not Assigned."

Geological Summary. The beautifully symmetrical Mount Cleveland stratovolcano is situated at the western end of the uninhabited Chuginadak Island. It lies SE across Carlisle Pass strait from Carlisle volcano and NE across Chuginadak Pass strait from Herbert volcano. Joined to the rest of Chuginadak Island by a low isthmus, Cleveland is the highest of the Islands of the Four Mountains group and is one of the most active of the Aleutian Islands. The native name, Chuginadak, refers to the Aleut goddess of fire, who was thought to reside on the volcano. Numerous large lava flows descend the steep-sided flanks. It is possible that some 18th-to-19th century eruptions attributed to Carlisle should be ascribed to Cleveland (Miller et al., 1998). In 1944 it produced the only known fatality from an Aleutian eruption. Recent eruptions have been characterized by short-lived explosive ash emissions, at times accompanied by lava fountaining and lava flows down the flanks.

Information Contacts: Alaska Volcano Observatory (AVO), a cooperative program of the U.S. Geological Survey, 4200 University Drive, Anchorage, AK 99508-4667, USA (URL: http://www.avo.alaska.edu/), the Geophysical Institute, University of Alaska, PO Box 757320, Fairbanks, AK 99775-7320, USA, and the Alaska Division of Geological and Geophysical Surveys, 794 University Ave., Suite 200, Fairbanks, AK 99709, USA; Earth Observatory, National Aeronautics and Space Administration (NASA) (URL: http://earthobservatory.nasa.gov/NaturalHarards/).