(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:(20090508/0106Z)
(3) Volcano:Veniaminof (CAVW# 1102-07-)
(4) Current Color Code:YELLOW
(5) Previous Color Code:
(6) Source:Alaska Volcano Observatory
(7) Notice Number:2009/A37
(8) Volcano Location:N 56 deg 11 min W 159 deg 23 min
(9) Area:Alaska Peninsula Alaska
(10) Summit Elevation:8225 ft (2507 m)
(11) 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.

(12) Volcanic cloud height:Unknown
(13) Other volcanic cloud information:Unknown
(14) 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.
(15) 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
(16) Next Notice:A new VONA will be issued if conditions change significantly or alert levels are modified. While a VONA is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu