(2) Issued:(20091019/1945Z)
(3) Volcano:Shishaldin (CAVW# 1101-36-)
(4) Current Color Code:GREEN
(5) Previous Color Code:
(6) Source:Alaska Volcano Observatory
(7) Notice Number:2009/A47
(8) Volcano Location:N 54 deg 45 min W 163 deg 58 min
(9) Area:Aleutians Alaska
(10) Summit Elevation:9373 ft (2857 m)
(11) Volcanic Activity Summary:Recent clear satellite views of Shishaldin show no activity at the volcano, with the last thermal anomaly observed on August 16. While seismicity remains variable, it is still within background levels for this volcano. Shishaldin has had intermittent periods of unrest since January 2009, typically accompanied by thermal anomalies and increased steam emissions. The apparent waning of this activity over the past two months prompts AVO to reduce the Aviation Color Code to GREEN and the Volcano Alert Level to NORMAL.
(12) Volcanic cloud height:Unknown
(13) Other volcanic cloud information:Unknown
(14) Remarks:Shishaldin volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 10 miles (16 km). A small summit crater typically emits a noticeable steam plume with occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, erupting atleast 28 times since 1775. Most of Shishaldin's eruptions have consisted of small ash and steam plumes, although the most recent eruption in April-May 1999 produced an ash column that reached a height of 45,000 ft above sea level.
(15) Contacts:Michelle Coombs, Acting Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7403

Steve McNutt, Coordinating Scientist, UAF
steve@giseis.alaska.edu (907) 474-7131
(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