Alaska Volcano Observatory

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, April 13, 2026, 3:47 PM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2026/A263
Location: N 52 deg 19 min W 174 deg 8 min
Elevation: 5030 ft (1533 m)
Area: Aleutians

Volcanic Activity Summary:

Seismic activity, sulfur dioxide emissions, and thermal anomalies at Korovin Volcano (located within the Atka Volcanic Complex) have declined over the past couple weeks and are now at background levels. The Aviation Color Code and the Alert Level for the Atka Volcanic Complex are being lowered to GREEN/NORMAL. Small explosive events can occur at Korovin Volcano without significant precursory unrest. Fallout of ash from such events is unlikely to extend beyond the upper flanks of the volcano.   

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

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 132347   
VONA
DTG:                    20260413/2347Z
VOLCANO:                ATKA VOLCANIC COMPLEX 311160
PSN:                    N5220 W17408
AREA:                   ALASKA
SOURCE ELEV:            5030FT AMSL
NOTICE NR:              2026/03
CURRENT COLOUR CODE:    GREEN
PREVIOUS COLOUR CODE:   YELLOW
SVO:                    ALASKA VOLCANO OBSERVATORY
ACT STS:                DECREASED UNREST
ONSET:                  NIL
DUR:                    NIL
VA CLD HGT:             NO VA CLD PRODUCED
HGT SOURCE:             NO VA CLD PRODUCED
MOV:                    NO VA CLD PRODUCED
CTC:                    MATT HANEY SIC, USGS MHANEY@USGS.GOV (907) 786-7497 DAVID FEE, CS, UAFGI
                        DFEE1@ALASKA.EDU (907) 378-5460
RMK:                    DECREASED SEISMICITY AND SO2 GAS DETECTIONS.
NXT NOTICE:             A NEW VONA WILL BE ISSUED IF COND CHANGE SIGNIFICANTLY OR IF THE COLOR CODE CHANGES
NNNN