Printer friendly versionALASKA VOLCANO OBSERVATORY WEEKLY UPDATEFriday, September 16, 2011 12:14 PM AKDT (Friday, September 16, 2011 20:14 UTC)CLEVELAND VOLCANO
52°49'20" N 169°56'42" W, Summit Elevation 5676 ft (1730 m)
Current Volcano Alert Level: WATCH
Current Aviation Color Code: ORANGE
The eruption of Cleveland Volcano continues with sustained slow growth of the lava dome in the summit crater. Analysis of TerraSAR-X satellite radar images through September 9 indicate that the dome now occupies the entire crater floor (about 150 by 150 m across), but is still lower than the crater rim. Thermal anomalies were observed in satellite data during periods of clear weather this past week and were consistent with continued eruption of lava. No ash emissions have been observed during this eruption, which began in mid-July, 2011.
The latest episode of dome growth resumed around September 3. A growing lava dome in the crater increases the possibility of an explosive eruption, but does not necessarily indicate that one will occur. Short-lived explosions could produce ash clouds that 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, it could overflow the crater rim to produce a lava flow and/or collapse to produce pyroclastic flows. Collapse of a lava flow or dome would likely 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.OTHER ALASKA VOLCANOES
Seismic activity is 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, Korovin, 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.
VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu
RECORDING ON THE STATUS OF ALASKA'S VOLCANOES (907) 786-7478
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.