Printer friendly versionALASKA VOLCANO OBSERVATORY
Friday, July 20, 2007 10:25 AM AKDT (1825 UTC)
52°49'20" N169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch
An intense thermal anomaly and an associated steam/gas plume were observed at Cleveland volcano this morning in a satellite image from 1525 UTC (0725 ADT), indicating that low-level eruptive activity is occuring. Thus, the aviation color code is being increased to Orange, and the volcano alert level is being increased to Watch. Although no ash has been detected in satellite data, the possibility of an explosion sending an ash cloud to heights in excess of 20,000 ft above sea level has increased.
The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions with ash plumes that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.
Cleveland volcano forms the western half of Chuginadak Island, a remote and uninhabited island in the east central Aleutians. It is located about about 75 km (45 mi.) west of the community of Nikolski, and 1500 km (940 mi.) southwest of Anchorage. The volcano's most recent significant eruption began in February, 2001 and had 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. This eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in October 2006.
NORMAL Typical background activity of a volcano in a non-eruptive state
ADVISORY Elevated unrest above known background activity
WATCH Volcano is exhibiting heightened or escalating unrest with increased potential for eruptive activity
WARNING Highly hazardous eruption underway or imminent
ABBREVIATED AVIATION COLOR CODE KEY:
GREEN volcano is dormant; normal seismicity and fumarolic activity occurring
YELLOW volcano is restless; eruption may occur
ORANGE volcano is in eruption or eruption may occur at any time
RED significant eruption is occurring or explosive eruption expected at any time
Please see http://volcanoes.usgs.gov/2006/vhpalertlevel.pdf for a complete description of alert levels and color codes.
VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu
RECORDING ON THE STATUS OF ALASKA'S VOLCANOES (907) 786-7478
Tom Murray Scientist-in-Charge, USGS
firstname.lastname@example.org (907) 786-7497
Steve McNutt, Coordinating Scientist, UAF
email@example.com (907) 474-7131
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.