USGS Volcano Notice for Aviation - DOI-USGS-AVO-2024-09-25T23:16:58+00:00

(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20250221/0611Z)
(3) Volcano:	Atka volcanic complex (VNUM #311160)
(4) Current Color Code:	ORANGE
(5) Previous Color Code:	GREEN
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2024/A652
(8) Volcano Location:	N 52 deg 19 min W 174 deg 8 min
(9) Area:	Aleutians
(10) Summit Elevation:	5030 ft (1533 m)
(11) Volcanic Activity Summary:	A single, small explosive event was detected in local seismic and infrasound data at 4:26 UTC (7:26 pm AKST) at the Atka volcanic complex. As a result, the Aviation Color Code and Alert Level has been changed to ORANGE/WATCH. The explosive event was short in duration (less than 10 seconds), and it is likely that a small amount of volcanic ash was erupted during this event. A meteorological cloud deck at an altitude of 8,000 to 10,000 ft above sea level obscured direct satellite observations, but no ash emissions were observed above the clouds. There have been no further explosive events observed and no noticeable change in seismic activity. Local seismic and infrasound sensors and web cameras are used to monitor the Atka volcanic complex along with regional infrasound and lightning networks, and satellite data.
(12) Volcanic cloud height:	Less than 10,000 ft
(13) Other volcanic cloud information:	No ash seen in satellite data above met cloud deck
(14) 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.
(15) Contacts:	Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497 Ronni Grapenthin, Acting Coordinating Scientist, UAFGI, rgrapenthin@alaska.edu (907) 378-5460
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