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ALASKA VOLCANO OBSERVATORY
Friday September 27, 2002 11:00 AM ADT (1900 UTC)
MT. VENIAMINOF VOLCANO (CAVW #1102-07)
Summit Cone Elevation 7,073 ft (2,156 m)
Current Level of Concern Color Code: YELLOW
Unrest at Mt. Veniaminof volcano on the Alaska Peninsula continues. In early September, AVO seismometers began recording tremor and small earthquakes beneath the volcano. Since then, the intensity of this activity has fluctuated and is presently lower than when first noted on September 10-11. However, it remains above what we consider to be a background level established over the summer of 2002.
Visual observations of Veniaminof have been hampered by poor weather. On September 24, residents of Perryville, 35 km (22 mi) south of the volcano, reported and photographed small bursts of steam, possibly containing minor amounts of ash, rising just above the historically active intracaldera cinder cone. Without additional observations, we are unable to determine if this reflects very low-level eruptive activity or vigorous steaming from the cone. Poor weather in the area has also prevented frequent satellite views of the summit area. However, on several occasions of relatively clear conditions during the past week, AVO observed no signs of elevated temperature or ash emission.
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.
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.