Printer friendly versionALASKA VOLCANO OBSERVATORY
Thursday, August 30, 2007 11:30 PM AKDT (730 UTC)
55°24'57" N161°53'24" W, Summit Elevation 8261 ft (2518 m)
Current Aviation Color Code: ORANGE
Current Volcano Alert Level: Watch
At approximately 9:30 pm AKDT (0530 UTC August 31) National Weather Service observers in Cold Bay reported a substantial plume and associated lightning emanating from Pavlof Volcano up to 20,000 ft (6,000 m) above sea level. The plume was also visible in images from the Pavlof web camera located in Cold Bay. Although no ash is visible in satellite data, the occurrence of lightning increases the likelihood of ash in the plume. Airborne ash dispersion models indicate the possibility of light ash fall in the region of Sand Point.
If activity continues to increase in intensity, larger ash clouds that could affect higher-flying aircraft may be produced. The most immediate ground hazard in the vicinity of the volcano includes light ash fall on nearby communities. Previous historical eruptions from Pavlof caused only a few millimeters (about 1/10th of an inch) of ash to fall on King Cove, Nelson Lagoon, Cold Bay, and Sand Point. Mudflows in drainages from the flanks of the volcano, and lava flows and avalanching of hot debris on the upper reaches of the volcano are also of concern in the uninhabited areas around the volcano. Satellite and seismic data and eyewitness observations suggest most of the surface lava activity is occurring on the southeast sector of the steep-sided volcano; this suggests that the Pacific Ocean side of the volcano is at most risk from avalanching hot debris.
At this time, we expect this eruption to follow the pattern of previous eruptions. The last eruption of Pavlof began in September 1996 and consisted of a several-month-long series of ash explosions, lava-fountaining, and lava-flow production. Ash clouds reached as high as 30,000 ft ASL on one occasion. However, most ash clouds were below 20,000 ft ASL. Prior to 1996, Pavlof erupted in 1986 sending ash as high as 49,000 ft ASL on at least one occasion. A hazard assessment for Pavlof and the Emmons Lake volcanic center is available on the web at http://www.avo.alaska.edu/pdfs/SIR2006-5248.pdf
Pavlof volcano is located on the southwestern end of the Alaska Peninsula. Pavlof is a stratovolcano which rises to an elevation of 8262 feet. With almost 40 historic eruptions, it is one of the most consistently active volcanoes in the Aleutian arc. Eruptive activity is generally characterized by sporadic strombolian fountaining continuing for a several-month period. The community of Cold Bay is located 60 km (37 miles) to the southwest of Pavlof.
VOLCANO ALERT LEVELS:
NORMAL Typical background activity of a volcano in a non-eruptive state
ADVISORY Elevated unrest above known background activity
WATCH Volcano is exhibiting heightened or escalating unrest with increased potential for eruptive activity
WARNING Highly hazardous eruption underway or imminent
ABBREVIATED AVIATION COLOR CODE KEY:
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
Please see http://volcanoes.usgs.gov/2006/vhpalertlevel.pdf for a complete description of alert levels and color codes.
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, 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.