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ALASKA VOLCANO OBSERVATORY
Monday January 6, 2003 04:30 PM AST (01:30 UT January 7)
MT. VENIAMINOF VOLCANO (CAVW #1102-07)
56°10'N 159°23'W, Summit Cone Elevation 7,073 ft (2,156 m)
Current Level of Concern Color Code: YELLOW
Previous Level of Concern Color Code: GREEN
Seismic activity at Mt. Veniaminof volcano on the Alaska Peninsula has been increasing since mid-December and the color code for Mt. Veniaminof is now raised to YELLOW from Green. AVO sees no indications of an imminent eruption at this time though low-level steaming and minor ash emissions may occur.
Increased seismic activity in September caused AVO to raise the color code for Veniaminof from Green to Yellow at that time. Visual and satellite observations suggested minor explosive activity. Seismic activity diminished and the color code was subsequently lowered to Green on November 18. Activity picked up again in December as the number of small events increased. Observers in Perryville could see the volcano December 21-22 and reported that the intracaldera cone "was covered with ash and there was darkened snow all around the cone". Beginning on December 31, there have been periods of nearly constant seismic activity. This sustained increase in seismicity prompts the change in the Level of Concern to Yellow.
No thermal anomalies have been observed from satellite data.
AVO will continue to monitor the situation closely, and will issue further updates as information becomes available.
Mt. Veniaminof volcano is an andesitic stratovolcano with an ice-filled, 10-km diameter summit caldera located on the Alaska Peninsula, 775 km (480 mi) southwest of Anchorage and 35 km (22 mi) north of Perryville. Veniaminof is one of the largest and most active volcanoes in the Aleutian Arc and has erupted at least 12 times in the past 200 years. The most recent eruption occurred in 1993-95 and came from an intracaldera cinder and spatter cone in the northwest sector of the caldera. The Strombolian-style eruption was characterized by intermittent, low-level emissions of steam and ash, and production of a small lava flow that melted a pit in the caldera ice field. Previous historical eruptions have produced ash plumes that reached 6,000 m (20,000 ft) above sea level and ash fallout that affected areas within about 40 km (25 mi) of the volcano.
For additional information and photographs of recent historical eruptions at Veniaminof, please visit our web site: http://www.avo.alaska.edu/avo4/atlas/Veniaminof.htm