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ALASKA VOLCANO OBSERVATORY
Monday, February 23, 2004 01:00 PM AST (22:00 UTC)
MOUNT 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: GREEN
Last week, AVO received several reports of small ash clouds rising
several hundred feet above the intracaldera cinder and spatter cone of
Mount Veniaminof volcano on the Alaska Peninsula. Residents of Perryville
reported a "black puff" of ash on February 16 followed by strong steaming,
and a pilot reported a small black ash cloud on February 19. Later
analysis of a satellite image from 23:10 UTC (2:10 pm AST) on February 19
showed a small, dark trail on the snow leading away from the intracaldera
cone. This was likely a very localized ash deposit. No significant
seismic activity or thermal anomalies in satellite data were recorded
during the week.
Due to the lack of significant seismic activity beneath the volcano,
AVO concludes that these small ash clouds are the result of minor
explosions caused by the heating of ground water below the intracaldera
cone. Such activity is not unexpected at Veniaminof and may continue to
occur intermittently. By itself, this activity does not indicate more
vigorous eruptive activity is imminent or even likely. Therefore the color
code for Veniaminof remains at GREEN.
AVO will continue to monitor activity at Mount Veniaminof using data
from the seismic network and satellites in addition to visual reports.
Mount 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 (~ 300 km3) and most active
volcanic centers in the Aleutian Arc and has erupted at least 12 times in
the past 200 years. The most recent eruption of the volcano occurred in
1993-95 and was a moderate Strombolian eruption from the main intracaldera
cone in the northwest sector of the caldera above Cone Glacier. The
eruption was characterized by intermittent low-level emissions of steam and
ash, and a small lava flow was extruded into the summit caldera ice field
producing an ice pit. Minor explosions producing small ash clouds very
similar to those reported last week occurred in 2002. Previous historical
eruptions have produced ash plumes that reached 6,000 m (20,000 ft) above
sea level and ash fallout that blanketed areas within about 40 km (25 mi)
of the volcano.
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
email@example.com (907) 786-7497
John Eichelberger, Coordinating Scientist, UAF-GI
firstname.lastname@example.org (907) 474-5530
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.