(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:(20140130/2039Z)
(3) Volcano:Shishaldin (CAVW# 1101-36-)
(4) Current Color Code:YELLOW
(5) Previous Color Code:green
(6) Source:Alaska Volcano Observatory
(7) Notice Number:2014/A3
(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:The Alaska Volcano Observatory is raising the Aviation Color Code to YELLOW and the Alert Level to ADVISORY at Shishaldin Volcano based on satellite observations over the past day of increased surface temperatures in the summit crater, as well as increased emissions of steam observed yesterday in satellite and web camera images. These observations represent a departure from normal background activity at Shishaldin, but do not necessarily indicate that an eruption will occur. Similar levels of unrest were last noted during 2009, and did not result in an eruption.

Shishaldin is monitored by a local seismic network, satellite data, web camera, telemetered geodetic network, and distant infrasound networks. Seismic monitoring of Shishaldin is significantly impaired due to equipment failures of seismic stations close to the volcano. We hope to be able to detect significant explosive activity (should it occur) using remaining functioning seismic stations in the region, satellite, and distant infrasound networks.

AVO will continue to watch Shishaldin carefully for additional signs of increased unrest.
(12) Volcanic cloud height:None observed.
(13) Other volcanic cloud information:None observed.
(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:John Power, Scientist-in-Charge, USGS
jpower@usgs.gov (907) 786-7497

Jeff Freymueller, Coordinating Scientist, UAFGI
jeff.freymueller@gi.alaska.edu (907) 322-4085
(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