(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20210402/1735Z)
(3) Volcano:	Shishaldin (VNUM #311360)
(4) Current Color Code:	GREEN
(5) Previous Color Code:	UNASSIGNED
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2021/A109
(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:	Several seismic stations in the Shishaldin network are now operating after being offline for many months this winter. Data from these stations have improved the Alaska Volcano Observatory's monitoring capability, and allows for location of small local earthquakes, thus the Aviation Color Code is now GREEN and the Volcano Alert Level NORMAL. The Alaska Volcano Observatory continues to monitor Shishaldin with the local seismic, GPS, and tilt stations, web camera imagery, remote infrasound and lightning networks, and satellite images.
(12) Volcanic cloud height:	na
(13) Other volcanic cloud information:	na
(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:	Matthew Haney, Acting Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497 David Fee, Coordinating Scientist, UAFGI dfee1@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

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AVO/USGS Volcanic Activity Notice

Volcano: Shishaldin (VNUM #311360)

Current Volcano Alert Level: NORMAL
Previous Volcano Alert Level: UNASSIGNED

Current Aviation Color Code: GREEN
Previous Aviation Color Code: UNASSIGNED

Issued: Friday, April 2, 2021, 9:35 AM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2021/A109
Location: N 54 deg 45 min W 163 deg 58 min
Elevation: 9373 ft (2857 m)
Area: Aleutians

Volcanic Activity Summary: Several seismic stations in the Shishaldin network are now operating after being offline for many months this winter. Data from these stations have improved the Alaska Volcano Observatory's monitoring capability, and allows for location of small local earthquakes, thus the Aviation Color Code is now GREEN and the Volcano Alert Level NORMAL.

The Alaska Volcano Observatory continues to monitor Shishaldin with the local seismic, GPS, and tilt stations, web camera imagery, remote infrasound and lightning networks, and satellite images.

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

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: Matthew Haney, Acting Scientist-in-Charge, USGS
mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI
dfee1@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.

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