Printer friendly versionALASKA VOLCANO OBSERVATORY
Friday, April 28, 2006 9:45 AM AKDT (1745 UTC)
59°21'48"N 153°26'W , Summit Elevation 4134 ft (1260 m)
Current Level of Concern Color Code: YELLOW
Previous Level of Concern Color Code: ORANGE
Based on the current level of activity at Augustine, we are lowering the Level of Concern Color Code from ORANGE to YELLOW.
Data and observations currently indicate that the growth of the summit lava dome and lava flows has stopped, or continues only at a very low rate. Seismic data show that rock fall and avalanche events are still occurring, but at a diminished level. Visual observations and satellite data show that there have not been any detectable changes at the summit over the last few weeks.
Despite the apparent cessation of lava dome growth, the new dome and lava flows are still highly unstable, and rock falls and avalanches are still occurring and may continue for several weeks or months. The north flank of the island is the area most susceptible to rock falls and avalanches, and the steep ends of the lava flows are also places where rock fall activity may continue. These areas are considered very hazardous. Small, dilute ash clouds produced by rock falls and avalanches may still develop, but these ash clouds are unlikely to extend beyond Augustine Island.
Some indicators suggest that magma is still present at shallow levels. AVO will continue to make volcanic gas measurements and recent measurements indicate that levels are still above background and likely indicate degassing of shallow magma. Weak thermal anomalies persist in satellite data, consistent with slow cooling of the lava dome and continued venting of hot gases.
Despite the volcano's current quiet state, renewed eruptive activity is possible. AVO expects that a renewal of explosive activity or lava extrusion would likely be preceded by increases in seismicity, gas output, and deformation.
Brief, unexpected explosions are still possible if hot gas and rocks interact with groundwater, but such explosions are unlikely to produce ash that would travel far beyond the island.
AVO continues to monitor Augustine closely and the observatory will remain staffed 24/7 until conditions at the volcano approach background levels.
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
Chris Waythomas, Acting Scientist-in-Charge, USGS
firstname.lastname@example.org (907) 786-7497
Chris Nye, Acting Coordinating Scientist, UAF-GI
email@example.com (907) 474-7430
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.