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ALASKA VOLCANO OBSERVATORY
Friday, October 4, 2002 11:30 AM ADT (19:30 UT)
MT. VENIAMINOF VOLCANO (CAVW #1102-07)
Summit Cone Elevation 7,073 ft (2,156 m)
Current Level of Concern Color Code: YELLOW
Mt. Veniaminof volcano on the Alaska Peninsula remained restless this week. Although current seismic activity is lower than when first noted in early September, it is still above what we consider to be a background level established during the summer of 2002.
Visual observations of Veniaminof have been intermittent and inconclusive. AVO has received reports ranging from minor steam and possible ash emissions to no sign of activity. A satellite image recorded on October 2 suggests an apparent gray, diffuse deposit extending across the caldera from the historically active intracaldera cinder cone. This could reflect a small explosion, or, vigorous steam emission, or, redistribution of material on the cone by strong winds. No thermal anomalies have been observed in satellite views. The activity is minor, and the exact nature of the unrest remains unknown.
The Level of Concern Color Code will remain YELLOW due to the continuing seismicity and reports of unusual steaming. 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 was a moderate Strombolian eruption from a cinder and spatter cone in the northwest sector of the caldera. The 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.