Volcano: Gareloi (VNUM #311070)
Current Volcano Alert Level: NORMAL
Previous Volcano Alert Level: ADVISORY
Current Aviation Color Code: GREEN
Previous Aviation Color Code: YELLOW
Issued: Tuesday, October 6, 2026, 10:37 AM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2026/A762
Location: N 51 deg 47 min W 178 deg 47 min
Elevation: 5161 ft (1573 m)
Area: Aleutians
Summary: Unrest has declined. Color Code and Alert Level Level lowered to GREEN/NORMAL.
Volcanic Activity:
Unrest has declined to background levels following the small explosion at Mount Gareloi on October 1, 2026. The minor explosion is interpreted as an isolated event related to persistent hydrothermal activity, rather than an indication of increased volcanic activity. The Aviation Color Code and Alert Level are being lowered to GREEN/NORMAL.
Remarks:
Mount Gareloi, which makes up all of Gareloi Island, is a stratovolcano located in the Delarof Islands group of the Aleutian Islands, about 2,000 km (1,242 mi) west-southwest of Anchorage and about 150 km (93 mi) west of Adak, the westernmost community in Alaska. This small volcano is 10 × 8 km (6.2 × 5.0 mi) in diameter at its base with two summits, separated by a narrow saddle. The northern, slightly higher peak contains crater about 300 m (1,000 ft) across. The southern summit has a crater open to the south and a persistent degassing vent (fumarole) on its western rim. Gareloi has been one of the most active in the Aleutians since the 1740s, with 16 reports of eruptive activity at Gareloi since 1760. In 1929, its largest historical eruption produced sixteen small south- to southeast-trending craters that extend from the southern summit to the coast, as well as lava flows and pyroclastic deposits on the southeastern flank of the volcano. Eruptions of Gareloi commonly produce ash clouds and lava flows, and the primary hazard is airborne clouds of ash that could affect aircraft. Since seismic instruments were installed in 2003, they have detected small but consistent seismic signals from beneath Mount Gareloi’s edifice.
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 061837 VONA DTG: 20261006/1837Z VOLCANO: GARELOI 311070 PSN: N5147 W17848 AREA: ALASKA SOURCE ELEV: 5161FT AMSL NOTICE NR: 2026/02 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: AVO DUTY SCIENTIST 907-786-7497 RMK: VOLCANIC ACTIVITY DECLINED NXT NOTICE: A NEW VONA WILL BE ISSUED IF COND CHANGE SIGNIFICANTLY OR IF THE COLOR CODE CHANGES NNNN
Hazard Notification System (HANS) for Volcanoes at volcanoes.usgs.gov/hans2/