Printer friendly versionALASKA VOLCANO OBSERVATORY
Friday, February 17, 2006 4:25 PM AKST (125 UTC)
59°21'48"N 153°26'W , Summit Elevation 4134 ft (1260 m)
Current Level of Concern Color Code: ORANGE
Activity continues at Augustine Volcano. Yesterday afternoon, an AVO observation flight crew obtained good views of the summit of Augustine. A new, steaming, blocky lava dome now occupies the summit crater at Augustine. The dome fills much of the crater and extends as a rubbly tongue northward 500-800 m (0.3 – 0.5 mi) down the upper north flank of the volcano. Dark aprons of collapse debris, including large steaming blocks, extend down slope to the north. The rim of the summit crater is largely snow-free and is mantled by thick, coarse, pyroclastic deposits, likely from the series of explosive events in January. This dome is a result of the largely quiet eruption of lava following the cessation of explosive activity on January 30. Some of the lava may have been emplaced prior to January 30. (Please see our web site for photographs: http://www.avo.alaska.edu/volcanoes/volcimage.php?volcname=Augustine)
AVO seismometers continue to record rock falls and signals produced by avalanching of debris, suggesting that the lava dome continues to grow or creep and experience occasional, minor collapse events. The number of events per day, however, has declined over the past week, suggesting the rate of lava production may be slowing.
When weather allows, satellite views of the volcano continue to show a thermal anomaly coinciding with the summit area. Airborne gas measurements this week show no significant change from earlier in the eruption. Values of sulfur dioxide emission are broadly consistent with similar types of dome building eruptions at other volcanoes.
A plume composed of variable amounts of gas, steam, and small amounts of ash is likely being emitted intermittently from Augustine's summit. Occasional, very localized ash clouds and light ash fall will be produced by collapses from the lava dome. Evidence of such localized ash fall on the flanks of the volcano was observed from the air this week.
During dome building eruptions, brief, energetic explosions can occur with little or no warning. Such explosions could produce larger amounts of ash leading to the formation of drifting ash clouds that could rise more than 25,000 feet above sea level.
Dome building eruptive activity will likely continue over the next few days or weeks and may continue intermittently over the next several months. As soon as weather and logistics allow, AVO scientists will be visiting the island.
AVO is monitoring the situation closely and the observatory remains staffed 24/7. For up-to-date Ashfall Advisories and wind trajectories, please refer to the National Weather Service website: http://pafc.arh.noaa.gov/augustine.php
ABBREVIATED COLOR CODE KEY
(contact AVO for complete description):
GREEN volcano is dormant; normal seismicity and fumarolic activity occurring
YELLOW volcano is restless; eruption may occur
ORANGE volcano is in eruption or eruption may occur at any time
RED significant eruption is occurring or explosive eruption expected at any time
VOLCANO INFORMATION ON THE INTERNET: http://www.avo.alaska.edu
RECORDING ON THE STATUS OF ALASKA'S VOLCANOES (907) 786-7478
Tom Murray, Scientist-in-Charge, USGS
firstname.lastname@example.org (907) 786-7497
Steve McNutt, Acting Coordinating Scientist, UAF-GI
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.