USGS Volcano Notice - DOI-USGS-AVO-2026-03-15T01:31:03+00:00

AVO/USGS Volcanic Activity Notice

Volcano: Atka volcanic complex (VNUM #311160)

Current Volcano Alert Level: ADVISORY
Previous Volcano Alert Level: WATCH

Current Aviation Color Code: YELLOW
Previous Aviation Color Code: ORANGE

Issued: Saturday, March 14, 2026, 5:36 PM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2026/A171
Location: N 52 deg 19 min W 174 deg 8 min
Elevation: 5030 ft (1533 m)
Area: Aleutians

Volcanic Activity Summary:

Correction: The previous report mistakenly raised to color code to Orange and Alert Level to Watch. The correct Aviation color code is Yellow and the Alert level is Advisory.

A substantial increase in seismicity was detected at the Atka volcano complex between 4:20-4:30 PM AKST March 14 (00:20-00:30 March 15 UTC). Small earthquakes and weak tremor have been observed over the past week and elevated levels of sulfur dioxide gas has been detected in satellite data. This activity increases the likelihood of explosive events at the one of the volcanoes within the Atka volcano complex, most likely Korovin. The Alaska Volcano Observatory is increasing the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

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:

Chris Waythomas, Acting Scientist-in-Charge, USGS cwaythomas@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 150136   
VONA
DTG:                    20260315/0136Z
VOLCANO:                ATKA VOLCANIC COMPLEX 311160
PSN:                    N5220 W17408
AREA:                   ALASKA
SOURCE ELEV:            5030FT AMSL
NOTICE NR:              2026/02
CURRENT COLOUR CODE:    YELLOW
PREVIOUS COLOUR CODE:   ORANGE
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:                    UNKNOWN
CTC:                    CHRIS WAYTHOMAS, ACTING SIC, USGS CWAYTHOMAS@USGS.GOV (907) 786-7497 DAVID FEE, CS,
                        UAFGI DFEE1@ALASK...
RMK:                    CORRECTION: COLOR CODE TO YELLLOW. INCREASE IN SEISMIC ACTIVITY AND SO2 EMISSIONS
                        DETECTED.
NXT NOTICE:             A NEW VONA WILL BE ISSUED IF COND CHANGE SIGNIFICANTLY OR IF THE COLOR CODE CHANGES
NNNN