ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, August 12, 2011, 2:09 PM AKDT (Friday, August 12, 2011, 22:09 UTC)

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

According to satellite and aerial views, the eruption of a slowly growing lava dome at Cleveland volcano continues. Observers on a August 8 NOAA flight photographed a small, dark-colored dome centered at the bottom of the summit crater. In the last clear satellite view of the summit on August 9 the lava dome was about 60 meters (197 feet) in diameter. Several satellite thermal anomalies were observed through August 9. Please see the AVO website ( https://www.avo.alaska.edu/volcanoes/volcimage.php?volcname=Cleveland ) for images and photos.

The persistent but generally weak thermal anomalies are indicative of a slow growing or cooling lava dome. The presence of a lava dome increases the possibility of an explosive, ash-producing eruption, but does not necessarily mean that explosive activity will occur over the coming days to weeks. Short-lived explosions from the summit vent have occurred during previous periods of unrest at Cleveland volcano, and such events can produce ash clouds that exceed 20,000 feet above sea level. Explosive events can occur without warning and ash clouds may go undetected in satellite imagery for hours.

Without a real-time seismic network on the volcano, AVO is unable to track local earthquake activity related to volcanic unrest, provide forecasts of eruptive activity, or confirmation of explosive, ash-producing events. AVO is monitoring the volcano using satellite data as it becomes available.





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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