Alaska Volcano ObservatoryWeekly UpdateFriday, May 9, 2008 1:34 PM AKDT (21:34 UTC)
CLEVELAND VOLCANO (CAVW #1101-24-)
52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Aviation Color Code: YELLOW
Current Volcano Alert Level: ADVISORY
Over the past two weeks, an increasing number of thermal anomalies observed in satellite images suggests that unrest at Cleveland Volcano has intensified. A small, low-altitude (less than 15,000ft) discrete ash cloud was observed in satellite images beginning Wednesday evening from 4:00PM AKDT, May 7 (0000UTC, May 8) until about 11:00PM AKDT, May 7 (0700UTC, May 8). A ship north of Nikolski reported a dusting of ash around the same time. No other ash clouds have been observed since Wednesday night, but the volcano has been largely obscured by clouds.
Wednesday’s ash cloud was likely a moderate explosion from the summit crater of Cleveland. Intermittent clear satellite views of the volcano over the last several years suggest intermittent, small explosions are common but do not produce significant amounts of ash or debris. The last ash cloud detected from Cleveland was on February 29, 2008. Th new ash cloud and more frequent thermal anomalies suggest that Cleveland may have entered a more active phase of activity with an increased possibility of additional explosions. However, this level of activity is not usual for Cleveland Volcano during the last several years. Therefore, AVO is currently holding the aviation color code at YELLOW and the volcano alert level at ADVISORY.
AVO monitors Cleveland Volcano with satellite imagery as weather allows. 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 of ash that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery. Please see http://www.avo.alaska.edu/activity/Cleveland.php for more information.
OTHER ALASKA VOLCANOES
Seismic activity is monitored in real time at 31 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. Wrangell, Spurr, Redoubt, Iliamna, Augustine, Fourpeaked, Snowy, Katmai, Griggs, Trident, Novarupta, Mageik, Martin, Ugashik-Peulik, Ukinrek Maars, Aniakchak, Veniaminof, Pavlof, Dutton, Isanotski, Shishaldin, Fisher, Westdahl, Akutan, Makushin, Okmok, Korovin, Great Sitkin, Kanaga, Tanaga, and Gareloi 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 volcano.
Please see http://www.avo.alaska.edu/color_codes.php for complete definitions of Aviation color codes and Volcanic activity 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:
Christina Neal, Acting Scientist-in-Charge, USGS
tneal@usgs.gov (907) 786-7497
Steve McNutt, Coordinating Scientist, UAFGI
steve@giseis.alaska.edu (907) 978-5458
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.
