Alaska Volcano Observatory

AVO/USGS Volcanic Activity Notice

Volcano: Aniakchak (VNUM #312090)

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

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


Issued: Tuesday, December 23, 2025, 11:23 AM AKST
Source: Alaska Volcano Observatory
Notice Number: 2025/A775
Location: N 56 deg 54 min W 158 deg 12 min
Elevation: 4400 ft (1341 m)
Area: Alaska Peninsula

Volcanic Activity Summary:

The Alaska Volcano Observatory (AVO) is no longer receiving data from seismic stations on Aniakchak Volcano due to an ongoing power outage at the receive facility in Port Heiden. As a result AVO unable to (1) assess whether the volcano may be building towards an eruption and (2) quickly confirm or dismiss reports of activity.  

Because this volcano is no longer seismically monitored at adequate levels, the Aviation Color Code and Volcano Alert Level are changed to UNASSIGNED/UNASSIGNED.  As at other volcanoes without real-time seismic networks, AVO will continue to use satellite data, regional seismic, infrasound and lightning networks, and reports from pilots and ground observers to detect signs of eruptive activity.

Recent Observations:
[Volcanic cloud height] none
[Other volcanic cloud information] none

Hazard Analysis:
[General hazards] none
[Ash cloud] none

Remarks:

Aniakchak volcano, located in the central portion of the Alaska Peninsula, consists of a stratovolcano edifice with a 6 mile (10 km) diameter summit caldera. The caldera-forming eruption occurred around 3,500 years ago. Post-caldera eruptions have produced lava domes, tuff cones, and larger spatter and scoria cone structures, including Half-Cone and Vent Mountain, all within the caldera. The most recent eruption occurred in 1931 and created a new vent and lava flows on the western caldera floor while spreading ash over much of southwestern Alaska. Aniakchak volcano is 16 miles (26 km) southeast of the nearest community, Port Heiden, and 416 miles (670 km) southwest of Anchorage, Alaska. It is located in Aniakchak National Monument and Preserve.

Contacts:

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

Jessica Larsen, Acting Coordinating Scientist, UAF jflarsen@alaska.edu (907) 378-5460

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.

Contact AVO: https://avo.alaska.edu/contact

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.

(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20251223/2023Z)
(3) Volcano:	Aniakchak (VNUM #312090)
(4) Current Color Code:	UNASSIGNED
(5) Previous Color Code:	GREEN
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2025/A775
(8) Volcano Location:	N 56 deg 54 min W 158 deg 12 min
(9) Area:	Alaska Peninsula
(10) Summit Elevation:	4400 ft (1341 m)
(11) Volcanic Activity Summary:	The Alaska Volcano Observatory (AVO) is no longer receiving data from seismic stations on Aniakchak Volcano due to an ongoing power outage at the receive facility in Port Heiden. As a result AVO unable to (1) assess whether the volcano may be building towards an eruption and (2) quickly confirm or dismiss reports of activity.   Because this volcano is no longer seismically monitored at adequate levels, the Aviation Color Code and Volcano Alert Level are changed to UNASSIGNED/UNASSIGNED.  As at other volcanoes without real-time seismic networks, AVO will continue to use satellite data, regional seismic, infrasound and lightning networks, and reports from pilots and ground observers to detect signs of eruptive activity.
(12) Volcanic cloud height:	none
(13) Other volcanic cloud information:	none
(14) Remarks:	Aniakchak volcano, located in the central portion of the Alaska Peninsula, consists of a stratovolcano edifice with a 6 mile (10 km) diameter summit caldera. The caldera-forming eruption occurred around 3,500 years ago. Post-caldera eruptions have produced lava domes, tuff cones, and larger spatter and scoria cone structures, including Half-Cone and Vent Mountain, all within the caldera. The most recent eruption occurred in 1931 and created a new vent and lava flows on the western caldera floor while spreading ash over much of southwestern Alaska. Aniakchak volcano is 16 miles (26 km) southeast of the nearest community, Port Heiden, and 416 miles (670 km) southwest of Anchorage, Alaska. It is located in Aniakchak National Monument and Preserve.
(15) Contacts:	Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497 Jessica Larsen, Acting Coordinating Scientist, UAF jflarsen@alaska.edu (907) 378-5460
(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.