ALASKA VOLCANO OBSERVATORY STATUS REPORT
U.S. Geological Survey
Tuesday, September 20, 2011, 12:56 PM AKDT (Tuesday, September 20, 2011, 20:56 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

Recent observations of Cleveland volcano show that the current eruption, characterized by effusion of lava within the summit crater continues. The size of the lava dome is now about 165 m (540 ft) in diameter compared to 150 m (490 ft) in diameter on September 9,2011. The growing lava dome remains entirely contained within the summit crater but is now approximately 20 meters below the eastern rim.

A growing lava dome in the crater increases the possibility of an explosive eruption, but does not necessarily indicate that one will occur. It is possible that explosions from the summit crater vent could produce ash clouds that may exceed 20,000 ft above sea level. These events can occur without warning and may go undetected in satellite imagery for hours. If lava dome growth continues, lava may overflow the crater rim to produce a lava flow and/or collapse to produce pyroclastic flows. Sudden collapse of the effusing lava could result in the generation of a volcanic ash cloud.

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 will continue to monitor the volcano using multiple sources of satellite data.





CONTACT INFORMATION:

Chris Waythomas, Acting Scientist-in-Charge, USGS
chris@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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