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ALASKA VOLCANO OBSERVATORY
Friday, April 16, 2004 12:15 PM ADT (20:15 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 episodes of volcanic tremor and volcanic earthquakes have
been recorded under Veniaminof over the past week. The tremor occurred in
pulses lasting several minutes, and the largest events were recorded on
most of the stations in the seismic network. This represents the strongest
activity since early 2003 when the volcano's color code was downgraded from
yellow to green.
No small bursts of ash from the intracaldera cone at Veniaminof have been
reported from Perryville or passing pilots, or noted in satellite data
since February of this year. No significant changes in the thermal
signature of the intracaldera cone have been noted in satellite data. 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.