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ALASKA VOLCANO OBSERVATORY
Friday, April 30, 2004 12:30 PM ADT (20:30 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: YELLOW
Unrest continues at Mount Veniaminof volcano and is characterized by small,
intermittent ash emissions, low-level volcanic tremor, and small volcanic
earthquakes. During this past week, small ash emissions were observed
during periods of clear weather on April 25 and 28. Ash clouds rose from
1,000 to 3,000 feet above the active cone (~8,000 to 10,000 feet or ~2,400
to 3,050 m above sea level), and during times of strong winds were observed
drifting for distances of less than 10 miles (~16 km). Seismic activity has
fluctuated, but remains above background levels. However, there are no
indications that more vigorous activity is imminent or even likely.
We expect that steam and ash emissions similar to those observed this week
may continue intermittently and could pose a hazard to people and
low-flying aircraft in the vicinity of the active cone.
AVO will continue to monitor activity at Mount Veniaminof using seismic
data, satellite images, internet camera data and observer reports. AVO has
increased the frequency of seismic data analysis to provide early warning
of increased activity, should it occur. Public access to internet camera
images (collected at Perryville) can be found at www.avo.alaska.edu.
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 significant 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 observed this past 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, 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
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.