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ALASKA VOLCANO OBSERVATORY
Friday, February 27, 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
Several low-level steam and ash emissions from Mount Veniaminof
volcano on the Alaska Peninsula were reported last week by residents of
Perryville and passing pilots. Satellite imagery on February 22 showed
very localized deposits within the ice-filled caldera (see
http://www.avo.alaska.edu/). Satellite passes since the 22nd have not
documented additional activity and AVO has received no further observations
from Perryville. Earthquake activity beneath the volcano remains at a low
level and the thermal signature of the intracaldera cone is unchanged from
previous months. These small ash bursts are most likely the result of
minor explosions caused by the heating of ground water below the
intracaldera cone. Such activity may be quite typical for Veniaminof and
could 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.
OTHER ALASKA VOLCANOES
Seismic activity is monitored in real time at 25 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, Veniaminof, Pavlof, Dutton,
Isanotski, Shishaldin, Fisher, Westdahl, Akutan, Makushin, Okmok, 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.
ABBREVIATED COLOR CODE KEY (contact AVO for complete description):
GREEN volcano is dormant; normal seismicity and fumarolic activity
YELLOW volcano is restless; eruption may occur
ORANGE volcano is in eruption or eruption may occur at any time
RED significant eruption is occurring or explosive eruption
expected at any time
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
firstname.lastname@example.org (907) 786-7497
John Eichelberger, Coordinating Scientist, UAF-GI
email@example.com (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.