AVO/USGS Volcanic Activity Notice
Volcano: Veniaminof (CAVW #1102-07-)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW
Issued: Thursday, May 7, 2009, 5:06 PM AKDT (20090508/0106Z)
Source: Alaska Volcano Observatory
Notice Number: 2009/A37
Location: N 56 deg 11 min W 159 deg 23 min
Elevation: 8225 ft (2507 m)
Area: Alaska Peninsula Alaska
Volcanic Activity Summary: Over the past day, earthquake activity has increased at Mount Veniaminof volcano. This increase is a significant change from normal background activity and AVO is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.
Visual reports today from Perryville indicate typical steaming from the summit caldera cone that has been the site of activity over recent years. No ash has been observed or detected in satellite images, but low-level ash emissions could occur with very little additional warning.
Currently the earthquakes are small in magnitude but are registering across the entire seismic network. Seismicity rates are high and have varied between 5-10 earthquakes per hour during quieter periods to 1-3 earthquakes per minute during more intense activity.
Please note that the Veniaminof web camera is currently not operating. Plans have been made to fix this camera, but the time frame is uncertain.
Recent Observations:
[Monitoring report] Typical low altitude steam emissions from the intracaldera cone were reported by local observers in Perryville.
[Volcanic cloud height] None
[Other volcanic cloud information] Unknown
Hazard Analysis:
[General hazards] Low-level ash emissions are typical of eruptions at Veniaminof volcano and can rise to altitudes as high as 20,000 ft above sea level. Airborne ash plumes can extend for tens of miles from the summit cone and may be hazardous to aircraft in the vicinity of the volcano. Ash fall is usually confined to the summit caldera and upper slopes of the volcano, but a trace of ash fall is possible within 25 miles of the volcano.
Remarks: 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 13 times in the past 200 years. Recent significant eruptions of the volcano occurred in 1993-95 and 2005. Both were moderate Strombolian eruptions 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, early 2005, and early November 2006, and February to March 2008. 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.
AVO will continue to monitor activity at Mount Veniaminof using seismic data, satellite images, and observer reports. Please see http://www.avo.alaska.edu/activity/Veniaminof.php for more information.
Contacts: Tom Murray, Scientist-in-Charge, USGS
tlmurray@usgs.gov (907) 786-7497
Mike West, Acting Coordinating Scientist, UAFGI
west@gi.alaska.edu (907) 474-6977
Next Notice: A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu
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.
