Taken from Ft Glenn on the east flank of Okmok Caldera. Courtesy of Lonnie Kennedy
AVO/USGS Volcanic Activity Notice
Volcano: Okmok
Current Volcano Alert Level: WARNING
Current Aviation Color Code: RED
Issued: Friday, July 25, 2008, 1:47 PM AKDT (20080725/2147Z)
Source: Alaska Volcano Observatory
Notice Number: 2008/A15
Location: N 53 deg 23 min W 168 deg 9 min
Elevation: 3520 ft (1073 m)
Area: Aleutians Alaska
Volcanic Activity Summary: The amplitude of seismic activity has increased in the past hour. Two pilots report ash to 40,000 feet. Satellite data confirm ash to at least 35,000. Based on these observations AVO is increasing the aviation color code at Okmok volcano to RED, and the alert level to WARNING.
Recent Observations:
[Monitoring report] Seismicity accelerated markedly about 12:30 pm today and remains at high levels.
[Other volcanic cloud information] Pilot reports and satellite data suggest ash cloud heights of 35,000 to 40,000 feet. Forecast winds would carry ash generally to the SE.
Hazard Analysis:
[Ash cloud] Pilot reports and satellite data suggest ash cloud heights of 35,000 to 40,000 feet. Forecast winds would carry ash generally to the SE.
[Ash fall] Minor ashfall may occur around the caldera, on the eastern portions of Umnak Island, and to the southeast of the island.
[Pyroclastic flow] The increased intensity of activity suggests that the likelihood of pyroclastic flow activity within the caldera has increased.
[Mud flow] Ongoing eruptions of ash are loading the upper slopes of Okmok Volcano with debris. Rainfall could mix with this ash fall to form mudflows and flooding especially on the eastern flank and eastern drainages from the Okmok caldera rim.
Remarks: Please see http://www.avo.alaska.edu/activity/Okmok.php for more information.
The nearest settlements are Nikolski, population about 35, roughly 45 miles west of the volcano, and a small number of people at the abandoned Fort Glenn military base 10 miles east of the volcano.
Contacts: John Power, Acting Scientist-in-Charge, USGS
jpower@usgs.gov, (907)786-7497
Steve McNutt, Coordinating Scientist, UAFGI
steve@giseis.alaska.edu (907)978-5458
Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
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.
