Remote Alaska volcano has calmed down after summertime unrest, observers say

This screenshot shows a portion of a high-resolution WorldView-3 satellite image of the active fumaroles (steam vents) at Mount Kupreanof on May 10, 2026. These fumaroles are associated with an active hydrothermal system at the volcano and are not related to any new volcanic activity. The small dark deposit is likely windblown dust from the snow-free fumaroles. (Image courtesy of AVO/USGS, ©2026 Maxar, USG Plus)

By James Brooks

Alaska Beacon

The Alaska Volcano Observatory on Tuesday lowered the alert level for Kupreanof Volcano on the Alaska Peninsula after weeks of declining activity at the remote peak.

Kupreanof hasn’t erupted in about 570,000 years, but in May, the observatory raised its alert level after detecting a growing number of nearby earthquakes and detecting significant amounts of sulfur dioxide, a chemical associated with magma moving beneath volcanoes.

Since May, the number of earthquakes has declined and the amount of sulfur dioxide has declined to normal background levels, the observatory said in a statement. 

Volcanoes without active unrest are typically designated “green” on the observatory’s color-coded alert spectrum, but Kupreanof isn’t normally monitored by the observatory, and Tuesday’s downgrade now labels it “unassigned.”

The observatory lacks the funding and resources to continuously monitor all of Alaska’s active volcanoes.

Alaska is the most seismically active state in the nation, with more volcanoes than every other state combined. Great Sitkin, a volcano in the Aleutian Islands, has been erupting since 2021. Shishaldin, on the Alaska Peninsula, last erupted in 2023 and has been experiencing signs of unrest since last year. 

The observatory, a collaboration between state and federal officials, monitors the state’s volcanoes for activity that could affect residents, travelers and aircraft.

• James Brooks Cascade is a longtime Alaska reporter who lives in Juneau. He previously worked at the Anchorage Daily News, Juneau Empire, Kodiak Mirror and Fairbanks Daily News-Miner. Alaska Beacon is part of States Newsroom, the nation’s largest state-focused nonprofit news organization.