USGS Volcano Notice - DOI-USGS-AVO-2026-05-11T22:22:27+00:00

AVO/USGS Volcanic Activity Notice

Volcano: Kupreanof (VNUM #312060)

Current Volcano Alert Level: ADVISORY
Previous Volcano Alert Level: UNASSIGNED

Current Aviation Color Code: YELLOW
Previous Aviation Color Code: UNASSIGNED

Issued: Tuesday, May 12, 2026, 9:01 AM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2026/A322
Location: N 56 deg W 159 deg 47 min
Elevation: 6217 ft (1895 m)
Area: Alaska Peninsula

Summary: Seismic activity and volcanic gas emissions increased over the past few months and continue at Mount Kupreanof. AVO is increasing the Color Code and Alert Level to YELLOW/ADVISORY.

Volcanic Activity:

Seismic activity and volcanic gas emissions increased over the past few months and now continue at elevated levels at Mount Kupreanof. This activity is likely caused by a magmatic intrusion beneath the volcano. The Alaska Volcano Observatory (AVO) is therefore increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY in response to this sustained volcanic unrest.

Summary of activity and hazards

Seismicity was first detected in February 2026 and has increased in recent months, with earthquakes as large as magnitude 3.1 detected.
Sulfur dioxide (SO₂) emissions were detected beginning on April 4 with emission rates of ~100 to 1,000 tons per day, which are well above the background rate of <100 tons per day.
These signals likely indicate a magmatic intrusion beneath Mount Kupreanof.
AVO is therefore increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY in response to this sustained volcanic unrest.
Data do not suggest an eruption is imminent and further signs of increased unrest would be expected prior to eruption.
There is no local monitoring network at Mount Kupreanof. Seismicity is detected using only regional stations, which limits detection of smaller events (magnitudes <2) and results in large location errors.

For more information:

AVO Information Statement from May 8, 2026, with further details about this activity and interpretations: https://avo.alaska.edu/news/hans/DOI-USGS-AVO-2026-05-08T19:12:14+00:00
Mount Kupreanof on the AVO website with information about the volcano and current monitoring data: https://avo.alaska.edu/volcano/kupreanof

Remarks:

Mount Kupreanof is a heavily glaciated stratovolcano on the Alaska Peninsula with no known historical eruptions. Very little is known about its eruptive history. A single debris flow or block-and-ash flow deposit with a suspected Holocene age has been mapped in a valley south of the volcano. Eruptions will likely produce lahars and pyroclastic flows on the volcano's flanks and into the surrounding uninhabited valleys. Ash plumes could affect communities and airplanes downwind of the volcano. A vigorous fumarole field just west of the summit produces persistent steam plumes.

There is no real-time geophysical monitoring network at Mount Kupreanof. The closest functioning seismometers are approximately 17 miles (27 km) to the east of the volcano as part of the Mount Veniaminof network. Mount Kupreanof is also monitored by satellite data, remote infrasound and lightning networks, and visual observations from pilots and mariners passing by the volcano.

Contacts:

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

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

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.

VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)

WMAK01 PAVO 121701   
VONA
DTG:                    20260512/1701Z
VOLCANO:                KUPREANOF 312060
PSN:                    N5601 W15947
AREA:                   ALASKA
SOURCE ELEV:            6217FT AMSL
NOTICE NR:              2026/01
CURRENT COLOUR CODE:    YELLOW
PREVIOUS COLOUR CODE:   UNASSIGNED
SVO:                    ALASKA VOLCANO OBSERVATORY
ACT STS:                HEIGHTENED UNREST
ONSET:                  NIL
DUR:                    NIL
VA CLD HGT:             NO VA CLD PRODUCED
HGT SOURCE:             NO VA CLD PRODUCED
MOV:                    NO VA CLD PRODUCED
CTC:                    AVO DUTY SCIENTIST 907-786-7497
RMK:                    SUSTAINED UNREST WITH EARTHQUAKES AND SO2 GAS DETECTIONS
NXT NOTICE:             A NEW VONA WILL BE ISSUED IF COND CHANGE SIGNIFICANTLY OR IF THE COLOR CODE CHANGES
NNNN