USGS Volcano Notice - DOI-USGS-AVO-2025-04-25T20:56:24+00:00

AVO/USGS Volcanic Activity Notice

Volcano: Atka volcanic complex (VNUM #311160)

Current Volcano Alert Level: ADVISORY
Previous Volcano Alert Level: NORMAL

Current Aviation Color Code: YELLOW
Previous Aviation Color Code: GREEN


Issued: Friday, April 25, 2025, 1:47 PM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2025/A262
Location: N 52 deg 19 min W 174 deg 8 min
Elevation: 5030 ft (1533 m)
Area: Aleutians

Volcanic Activity Summary:

A small, short-lived explosion was detected at the Atka volcanic complex this morning at 10:34 AKDT April 25 (18:34 UTC April 25) in local infrasound and seismic data. Processing of the local infrasound data indicates the explosion originated from the summit crater of Korovin, one of several volcanoes within the Atka volcanic complex. AVO is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

High clouds blocked the area at the time of the explosion, preventing satellite observations. Similar past events at the Atka volcanic complex did not result in a noticeable ashfall or ash cloud or other impacts.

Recent Observations:
[Volcanic cloud height] n/a
[Other volcanic cloud information] n/a
[Ballistics] n/a
[Lava flow/dome] n/a
[Lava flow] n/a

Hazard Analysis:
[General hazards] n/a
[Ash cloud] n/a
[Ashfall] n/a
[Lava flow/dome] n/a
[Mud flow] n/a
[Volcanic gas] n/a
[Other hazards] n/a
[Lava flow] n/a

Remarks:

The Atka volcanic complex forms the northern part of Atka Island, located about 16 km north of the community of Atka and 1,761 km southwest of Anchorage. The Atka volcanic complex includes a possible older caldera and several younger vents, including Korovin Volcano, Mount Kliuchef, and Sarichef Volcano. Korovin Volcano, a 1553-m-high (5030 ft) stratovolcano, has been the site of most historical volcanic activity, and has a small, roiling crater lake that occasionally produces energetic steam emissions. Korovin has erupted several times in the past 200 years, including 1973, 1987, and 1998, and has likely had small ash emissions as recently as 2005. Typical recent Korovin eruptions produce minor amounts of ash and occasional but small lava flows. Reports of the height of the ash plume produced by the 1998 eruption ranged as high as 10,600 m (35,000 feet) above sea level. Mount Kliuchef is composed of a series of five vents aligned northeast–southwest. The two main summit vents of Kliuchef appear relatively young and the easternmost was probably the source of an 1812 eruption that is sometimes attributed to Sarichef.

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

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.