Printer friendly versionALASKA VOLCANO OBSERVATORY
Friday, November 4, 2005 2:00 PM AKST (2300 UTC)
56.1956°N 159.3883°W, Summit Elevation 8225 ft (2507 m)
Current Level of Concern Color Code: YELLOW
A low-level, minor ash emission was observed coming from the intracaldera cone of Mount Veniaminof this morning in AVO webcam images from Perryville. This activity is above what we consider to be normal background. Thus, the color code for Mount Veniaminof has been upgraded to YELLOW.
The ash emission started at about 9:29 AM AST (1829 UTC) this morning. It was small, rising a few hundred meters (several hundred feet) above the cone, which has an elevation of 2,156 m (7,073 ft) above sea level. The discrete ash emission dissipated rapidly as it drifted towards the east. Ash fall is likely very minor, and confined to the summit caldera. Occasional steaming from the intracaldera cone has also been observed during the past two weeks.
Very weak seismic tremor and a few small discrete seismic events have been seen at the station closest to the active cone. However, there are no indications from seismic data that a significantly larger eruption is imminent. We expect that steam and ash emissions may continue intermittently and could pose a hazard to people and low-flying aircraft in the vicinity of the active cone.
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, having erupted at least 13 times in the past 200 years. Recent significant eruptions of the volcano occurred in 1993-95 and 2005. Both were moderate Strombolian epsiodes producing intermittent low-level jets of incandescent lava fragments and low-level emissions of steam and ash from the main intracaldera cone. During the 1993-95 activity, a small lava flow was extruded into the summit caldera ice field producing an ice pit. Minor ash-producing explosions occurred in 2002, 2004, and early 2005. 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.
ABBREVIATED COLOR CODE KEY
(contact AVO for complete description):
GREEN volcano is dormant; normal seismicity and fumarolic activity occurring
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.