USGS Volcano Notice - DOI-USGS-AVO-2025-05-05T17:00:22+00:00

AVO/USGS Volcanic Activity Notice

Volcano: Atka volcanic complex (VNUM #311160)

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

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


Issued: Monday, May 5, 2025, 12:00 PM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2025/A289
Location: N 52 deg 19 min W 174 deg 8 min
Elevation: 5030 ft (1533 m)
Area: Aleutians

Volcanic Activity Summary: No further explosive activity has been detected at the Atka volcanic complex since the small explosive event at 10:34 AKDT on April 25 (18:34 UTC on April 25). Thus, the Aviation Color Code and Alert Level are being reduced to GREEN/NORMAL.

Brief explosive events at Korovin Volcano can occur without significant precursory unrest. Fallout of ash is unlikely to extend much beyond the upper flanks of the volcano.Possible ash clouds generated by such events are expected to be small and dissipate quickly.

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

Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460

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.