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ALASKA VOLCANO OBSERVATORY
Friday January 17, 2003 9:30 AM AST (1830 UTC)
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
The elevated seismic activity that began mid-December, 2002 at Mt. Veniaminof volcano continues. During the past week, nearly constant periods of seismic activity have been recorded. Discrete seismic events occurred at a rate up to 1-2 events per minute, along with moderate levels of volcanic tremor. At this level of seismic unrest low-level steaming and minor ash-emissions may occur at any time. Clouds obscured the volcano during the week preventing satellite observations.
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. Beginning on December 31, there have been periods of nearly constant seismic activity. Due to the sustained increase in seismicity, the Level of Concern Color Code remains at YELLOW.
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
Seismic activity is monitored in real time at 24 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, Augustine, Snowy, Griggs, Katmai, Novarupta, Trident, Mageik, Martin, Aniakchak, Pavlof, Dutton, Isanotski, Shishaldin, Fisher, Westdahl, Akutan, Makushin, Great Sitkin, and Kanaga 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.