(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20190724/1939Z)
(3) Volcano:	Shishaldin (VNUM #311360)
(4) Current Color Code:	ORANGE
(5) Previous Color Code:	YELLOW
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:
(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:	The Alaska Volcano Observatory is raising the Aviation Color Code to ORANGE and the Alert Level to WATCH at Shishaldin Volcano. Field crews reported an active lava lake and minor spattering within the summit crater during a helicopter overflight. Elevated seismic activity continues similar to the past few weeks along with consistent elevated surface temperatures in satellite images. No lava or ash has erupted outside the summit crater at this time. Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.
(12) Volcanic cloud height:	None
(13) Other volcanic cloud information:	N/A
(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:	Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497 Jessica Larsen, Acting Coordinating Scientist, UAFGI jflarsen@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: WATCH
Previous Volcano Alert Level: ADVISORY

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

Issued: Wednesday, July 24, 2019, 11:39 AM AKDT
Source: Alaska Volcano Observatory
Notice Number:
Location: N 54 deg 45 min W 163 deg 58 min
Elevation: 9373 ft (2857 m)
Area: Aleutians

Volcanic Activity Summary: The Alaska Volcano Observatory is raising the Aviation Color Code to ORANGE and the Alert Level to WATCH at Shishaldin Volcano. Field crews reported an active lava lake and minor spattering within the summit crater during a helicopter overflight. Elevated seismic activity continues similar to the past few weeks along with consistent elevated surface temperatures in satellite images. No lava or ash has erupted outside the summit crater at this time.

Shishaldin is monitored by local seismic and infrasound sensors, satellite data, a web camera, a telemetered geodetic network, and distant infrasound and lightning networks.

Recent Observations:
[Volcanic cloud height] None
[Other volcanic cloud information] N/A
[Ballistics] Weak lava spattering confined to summit crater
[Lava flow] Active lava lake observed within summit crater

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: Michelle Coombs, Scientist-in-Charge, USGS
mcoombs@usgs.gov (907) 786-7497

Jessica Larsen, Acting Coordinating Scientist, UAFGI
jflarsen@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

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.

---