ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, September 3, 2010, 11:52 AM AKDT (Friday, September 3, 2010, 19:52 UTC)
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 remains at Volcano Alert Level ADVISORY and Aviation Color Code YELLOW. Satellite images throughout the week continued to detect a thermal anomaly in the volcano's summit area. The presence of a persistent thermal anomaly increases the likelihood of an ash emission event. AVO has received no reports of activity from pilots or mariners.
Without a real-time seismic network at Cleveland, AVO is unable to track local earthquake activity related to volcanic unrest. Short-lived explosions with ash clouds that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery for hours. Low-level ash emissions at Cleveland occur frequently and do not necessarily mean a larger eruption is imminent. AVO continues to monitor the volcano using 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 Nikolski, and 1500 km (940 mi) southwest of Anchorage. The volcano's most recent significant eruption was in July 2008 and produced an ash plume to over 6 km (20,000 ft) above sea level. Another significant eruption began in February, 2001 when 3 explosive events 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 June 2010.
OTHER ALASKA VOLCANOES
AVO has recently restored seismic networks on Veniaminof and Aniakchak volcanoes to full operation. Seismic activity is now 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, 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.
Chris Waythomas, Acting 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.