USGS Volcano Notice for Aviation - DOI-USGS-AVO-2023-10-30T11:47:57-08:00

(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20231030/2214Z)
(3) Volcano:	Aniakchak (VNUM #312090)
(4) Current Color Code:	UNASSIGNED
(5) Previous Color Code:	GREEN
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2023/A1557
(8) Volcano Location:	N 56 deg 54 min W 158 deg 12 min
(9) Area:	Alaska Peninsula
(10) Summit Elevation:	4400 ft (1341 m)
(11) Volcanic Activity Summary:	The Alaska Volcano Observatory (AVO) has experienced the failure of seismic monitoring equipment at Aniakchak Volcano and the remaining instrumentation is insufficient to establish that the volcano is at a typical background level. It is not possible to repair this equipment until next summer's field season. As a result, AVO is unable to (1) assess whether this volcano may be building towards an eruption and (2) quickly confirm or dismiss reports of activity. Because this volcano is no longer seismically monitored at adequate levels, the Aviation Color Code and Volcano Alert Level are changed to UNASSIGNED/UNASSIGNED. As at other volcanoes without real-time seismic networks, AVO will continue to use satellite data, regional seismic, infrasound and lightning networks, and reports from pilots and ground observers to detect signs of eruptive activity.
(12) Volcanic cloud height:	none
(13) Other volcanic cloud information:	none
(14) Remarks:	Aniakchak volcano, located in the central portion of the Alaska Peninsula, consists of a stratovolcano edifice with a 10 km (6 mile) diameter summit caldera. The caldera-forming eruption occurred around 3,500 years ago. Postcaldera eruptions have produced lava domes, tuff cones, and larger spatter and scoria cone structures including Half-Cone and Vent Mountain all within the caldera. The most recent eruption occurred in 1931 and created a new vent and lava flows on the western caldera floor while spreading ash over much of southwestern Alaska. Aniakchak volcano is 25 km (15 miles) southeast of the nearest community, Port Heiden, and 670 km (416 miles) southwest of Anchorage, Alaska.
(15) Contacts:	Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497 David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460
(16) Next Notice:	A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at http://www.avo.alaska.edu.