ALASKA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Friday, December 2, 2011, 11:41 AM AKST (Friday, December 2, 2011, 20:41 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
Satellite views show gradual subsidence and disintegration of the summit dome during the past two weeks. Elevated surface temperatures have been observed during periods of clear weather. This is to be expected due to the mass of hot lava that now fills the roughly 200-m-wide (660 feet) summit crater. AVO has received no reports of activity.
The new lava dome began growing at Cleveland in late July 2011 and eventually reached about 10 m (33 feet) below the crater rim. Throughout this period of unrest and eruption, AVO has not observed deposits or features indicative of explosions or ash emission. Cleveland's activity from late July to present can be characterized as an effusive lava eruption. The volume of the lava dome is about one million cubic meters (1.3 million cubic yards).
We are uncertain if the eruption is over or has merely paused. It is possible for effusion to resume at any time which could send lava over the crater rim and down the steep flanks of the volcano. Such lava flows could collapse and produce avalanches of hot debris that reach the sea and may be accompanied by small ash clouds.
It also remains possible for sudden explosions and ash emission to occur, and ash clouds exceeding 20,000 feet above sea level may develop. Such explosions and their associated ash clouds may go undetected in satellite imagery for hours. However, in cooperation with the University of Washington, AVO has implemented a lightning alarm system that may detect significant ash-producing events within minutes of onset. If a large explosive event occurs, seismic signals may be recorded on AVO seismic networks at nearby volcanoes. There is no real-time seismic monitoring network on Mt. Cleveland.
Additional information on Cleveland Volcano and the current activity may be found at this link:
Please see http://www.avo.alaska.edu/color_codes.php for complete definitions of Aviation color codes and Volcano alert levels.
John Power, Scientist-in-Charge, USGS
email@example.com (907) 786-7497
Steve McNutt, Coordinating Scientist, UAF
firstname.lastname@example.org (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.