(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20151120/2052Z)
(3) Volcano:	Shishaldin (VNUM #311360)
(4) Current Color Code:	YELLOW
(5) Previous Color Code:	ORANGE
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2015/A8
(8) Volcano Location:	N 54 deg 45 min W 163 deg 58 min
(9) Area:	Aleutians
(10) Summit Elevation:	9373 ft (2857 m)
(11) Volcanic Activity Summary:	No anomalous activity at Shishaldin has been observed in satellite data since weakly elevated surface temperatures were detected on October 16. Low-amplitude seismic tremor continues but is not considered to be indicative of an active eruption. AVO is therefore downgrading the status of Shishaldin volcano from aviation color code ORANGE to YELLOW and from volcano alert level WATCH to ADVISORY. AVO will continue to monitor Shishaldin with satellite, seismic and infrasound (pressure sensor) data.
(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 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 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 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

---

AVO/USGS Volcanic Activity Notice

Volcano: Shishaldin (VNUM #311360)

Current Volcano Alert Level: ADVISORY
Previous Volcano Alert Level: WATCH

Current Aviation Color Code: YELLOW
Previous Aviation Color Code: ORANGE

Issued: Friday, November 20, 2015, 11:52 AM AKST
Source: Alaska Volcano Observatory
Notice Number: 2015/A8
Location: N 54 deg 45 min W 163 deg 58 min
Elevation: 9373 ft (2857 m)
Area: Aleutians

Volcanic Activity Summary: No anomalous activity at Shishaldin has been observed in satellite data since weakly elevated surface temperatures were detected on October 16. Low-amplitude seismic tremor continues but is not considered to be indicative of an active eruption. AVO is therefore downgrading the status of Shishaldin volcano from aviation color code ORANGE to YELLOW and from volcano alert level WATCH to ADVISORY. AVO will continue to monitor Shishaldin with satellite, seismic and infrasound (pressure sensor) data.

Recent Observations:
[Volcanic cloud height] Unknown
[Other volcanic cloud information] Unknown

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 16 km (10 mi). A 200-m-wide (660 ft) funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 24 confirmed eruptions since 1775. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft above sea level.

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

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

---