(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20210331/1822Z)
(3) Volcano:	Tanaga (VNUM #311080)
(4) Current Color Code:	UNASSIGNED
(5) Previous Color Code:	GREEN
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2021/A108
(8) Volcano Location:	N 51 deg 53 min W 178 deg 8 min
(9) Area:	Aleutians
(10) Summit Elevation:	5925 ft (1806 m)
(11) Volcanic Activity Summary:	Low power likely due to snow cover has resulted in loss of operation and communication with all but two seismic stations on Tanaga. As a result, the Alaska Volcano Observatory can no longer locate earthquakes that could indicate unrest at Tanaga, and the Aviation Color Code and the Volcano Alert Level are now designated as UNASSIGNED. Additional seismic stations may come back online this spring as snowpack decreases. Any eruptive activity or unrest may still be detected with the remaining seismic stations, in regional infrasound networks, through detection of lightning, and/or monitoring of satellite images.
(12) Volcanic cloud height:	Unknown
(13) Other volcanic cloud information:	Unknown
(14) Remarks:
(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:

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AVO/USGS Volcanic Activity Notice

Volcano: Tanaga (VNUM #311080)

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

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

Issued: Wednesday, March 31, 2021, 10:22 AM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2021/A108
Location: N 51 deg 53 min W 178 deg 8 min
Elevation: 5925 ft (1806 m)
Area: Aleutians

Volcanic Activity Summary: Low power likely due to snow cover has resulted in loss of operation and communication with all but two seismic stations on Tanaga. As a result, the Alaska Volcano Observatory can no longer locate earthquakes that could indicate unrest at Tanaga, and the Aviation Color Code and the Volcano Alert Level are now designated as UNASSIGNED. Additional seismic stations may come back online this spring as snowpack decreases.

Any eruptive activity or unrest may still be detected with the remaining seismic stations, in regional infrasound networks, through detection of lightning, and/or monitoring of satellite images.

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

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

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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