ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, March 25, 2011, 1:51 PM AKDT (Friday, March 25, 2011, 21:51 UTC)

CLEVELAND VOLCANO (VNUM #311240)
52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Partly to mostly cloudy conditions obscured views of Cleveland volcano by satellite for most of the week. A cloud-free view of the volcano on March 23 showed no unusual activity. The last thermal anomaly detected at the volcano's summit was on March 11. No reports of activity have been received.

Without a real-time seismic network on Cleveland volcano, AVO is unable to detect local earthquake activity related to volcanic unrest and cannot rely on seismic data to forecast possible eruptive activity. Brief explosive bursts in the summit vent may generate ash clouds that could rise more than 20,000 ft. above sea level and drift from the volcano with the prevailing winds. Without a seismic network in place, the only way to detect such ash clouds is to observe them in satellite imagery. Satellite images of Cleveland volcano are acquired about every two hours. Small volume ash emissions occur frequently at Cleveland and do not necessarily mean a larger eruption is imminent. The last ash cloud we detected was on September 12, 2010. Weak thermal anomalies have been regularly observed in the summit crater for the past eight months through March 2011. AVO continues to monitor the volcano using satellite imagery, pilot reports, and local observations made by passing boats.


OTHER ALASKA VOLCANOES

Seismic activity is monitored in real time at 30 volcanoes in Alaska. Satellite images of all Alaskan volcanoes are analyzed daily for evidence of ash plumes and elevated surface temperatures. Some volcanoes may currently display anomalous behavior but are not considered to be at a dangerous level of unrest. Akutan, Aniakchak, Augustine, Dutton, Fisher, Gareloi, Great Sitkin, Griggs, Iliamna, Isanotski, Kanaga, Katmai, Korovin, Mageik, Makushin, Martin, Novarupta, Okmok, Pavlof, Redoubt, Shishaldin, Snowy, Spurr, Tanaga, Trident, Ugashik-Peulik, Ukinrek Maars, Veniaminof, Westdahl, and Wrangell volcanoes are in color code GREEN and volcano alert level Normal. All are at or near normal levels of background seismicity. AVO did not detect ash plumes or significant elevated surface temperatures in the vicinity of any of these volcanoes.

Please see http://www.avo.alaska.edu/color_codes.php for complete definitions of Aviation color codes and Volcano alert levels.

VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu
RECORDING ON THE STATUS OF ALASKA'S VOLCANOES (907) 786-7478

CONTACT INFORMATION:

John Power, Scientist-in-Charge, USGS
jpower@usgs.gov (907) 786-7497

Steve McNutt, Coordinating Scientist, UAF
steve@giseis.alaska.edu (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.

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