Printer friendly versionALASKA VOLCANO OBSERVATORY
Friday, May 26, 2006 2:20 PM AKDT (2220 UTC)
59°21'48"N 153°26'W , Summit Elevation 4134 ft (1260 m)
Current Level of Concern Color Code: YELLOW
Augustine was seismically quiet for most of the last week. Last night, however, several rockfall-related signals were detected by the seismic network. Two particularly large events occurred at 1:06 AM ADT (9:06 UTC) and 7:48 AM ADT (15:48 UTC) this morning. The second was the larger of the two, and the on-island web camera showed that it was accompanied by an ash cloud that likely rose to several thousand feet above the summit and drifted to the south. This event may have had a small explosive component.
Satellite views throughout the week revealed weak thermal anomalies, consistent with the slow cooling of the new lava dome and flows.
Lava effusion, if still ongoing, is occurring at rates too low to be detected by visual, seismic, or satellite data.
Further large rockfalls and/or block-and-ash flows like the ones of this morning could occur with little or no warning, but ash will likely not travel far beyond Augustine Island.
AVO continues to monitor Augustine closely.
56°11'44"N 159°23'18"W , Summit Elevation 8225 ft (2507 m)
Current Level of Concern Color Code: YELLOW
Seismicity at Veniaminof remained low this week. Exceptionally clear weather for much of the week provided clear web camera and satellite views. Web camera views showed weak steam plumes occasionaly emanating from the active vent. Satellite data showed only a weak daytime thermal anomaly on May 25 that was likely the result of solar heating of the dark intracaldera cone.
Intermittent production of short-lived, very small-volume steam and ash bursts from the intracaldera cone has been typical of this volcano over the past few years. There are no indications that a larger eruption is imminent. Ash clouds and fallout from these events are not likely to extend beyond the caldera rim, but could pose a hazard to people and low-flying aircraft in the vicinity of the active cone.
52°49'24"N 169°56'35"W , Summit Elevation 5676 ft (1730 m)
Current Level of Concern Color Code: Not Assigned
On May 23, AVO received a report from the International Space Station indicating that a plume was observed moving west from Cleveland Volcano at 3 PM ADT (2300 UTC). The volcanic plume was seen in AVHRR satellite data beginning from 3:07 PM ADT (2307 UTC). By 5:00 PM AKST (0100 UTC) May 23 the ash plume had detached from the vent and was approximately 82 miles (130 kilometers) SW of Cleveland Volcano. Satellite data showed a cloud height of about 20,000 ft asl. The plume was no longer detectable in satellite imagery by 4:57 AM ADT (12:57 UTC) May 24. In response to the event, AVO raised the Level of Concern Color Code to YELLOW.
Since May 23, no new information about ash emissions has been received, nor have indications of continuing activity been detected from satellite data for the volcano. This short-lived event was typical of recent Cleveland activity.
Earlier today, AVO downgraded the Level of Concern Color Code for Cleveland from YELLOW to Not Assigned
. Because Cleveland is not monitored with real-time seismic instrumentation, we do not assign it Color Code Green, but instead leave it "Not Assigned".
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. Wrangell, Spurr, Redoubt, Iliamna, Snowy, Griggs, Katmai, Novarupta, Trident, Mageik, Martin, Peulik, Ukinrek Maars, Aniakchak, Pavlof, Dutton, Isanotski, Shishaldin, Fisher, Westdahl, Akutan, Makushin, Okmok, Korovin, Great Sitkin, Kanaga, Tanaga, and Gareloi volcanoes are in color code GREEN. 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 volcano.
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
Jessica Larsen, Coordinating Scientist, UAF-GI
email@example.com (907) 474-7992
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.