ALASKA VOLCANO OBSERVATORY WEEKLY UPDATEFriday, August 27, 2010 1:10 PM AKDT (Friday, August 27, 2010 21:10 UTC)

CLEVELAND VOLCANO (CAVW #1101-24-)
52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Cleveland Volcano was elevated to volcano alert level ADVISORY and aviation color code YELLOW yesterday. A persistent thermal anomaly was observed in satellite imagery from most of last week and on Monday and Tuesday of this week. Weather conditions have been cloudy at the volcano for the rest of this week. A pilot report submitted on Thursday (Aug. 26) reported that no steam or ash were visible from the volcano. AVO continues to monitor the volcano using satellite imagery.

Without a real-time seismic network at Cleveland, AVO is unable to track local earthquake activity related to volcanic unrest. Low-level ash emissions at Cleveland occur frequently and do not necessarily mean a larger eruption is imminent. Short-lived explosions with ash clouds or 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 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 was in July of 2008 and produced an ash plume to over 6 km (20,000 ft) above sea level. Another significant eruption began in February, 2001 and it produced 3 explosive events that produced ash clouds as high as 12 km (39,000 ft) above sea level. The 2001 eruption also produced a rubbly lava flow and hot avalanche that reached the sea. The most recent minor ash emissions were observed in and June 2010.

OTHER ALASKA VOLCANOES

Seismic activity is monitored in real time at 27 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, Augustine, Dutton, Fisher, Gareloi, Great Sitkin, Griggs, Iliamna, Isanotski, Kanaga, Katmai, Mageik, Makushin, Martin, Novarupta, Okmok, Pavlof, Redoubt, Shishaldin, Snowy, Spurr, Tanaga, Trident, Ugashik-Peulik, Ukinrek Maars, 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:
Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@usgs.gov (907) 786-7497

Jon Dehn, Acting Coordinating Scientist, UAF
jdehn@gi.alaska.edu (907) 474-6499

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.