USGS Volcano Notice for Aviation - DOI-USGS-AVO-2024-02-11T21:12:44+00:00

(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20240211/2146Z)
(3) Volcano:	Shishaldin (VNUM #311360)
(4) Current Color Code:	ORANGE
(5) Previous Color Code:	YELLOW
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2024/A152
(8) Volcano Location:	N 54 deg 45 min W 163 deg 58 min
(9) Area:	Aleutians
(10) Summit Elevation:	9373 ft (2857 m)
(11) Volcanic Activity Summary:	Volcanic activity at Shishaldin Volcano has increased slightly, and minor ash emissions were observed in a web camera image from 18:25 UTC (9:25 AM) this morning. The ash in the web camera image extends from the summit crater and drapes down over the volcano's north flank. This ash emission episode corresponds with seismic signals typically associated with surficial mass flows. The low-level ash cloud may result from a non-eruptive collapse of previously emplaced ash and pyroclastic debris on the upper part of the Shishaldin cone. Clouds have obscured summit views in web camera images after the 18:25 UTC image. No ash clouds have been observed in satellite imagery. Thus, the Aviation Color Code and the Volcano Alert Level are being raised to ORANGE/WATCH. Shishaldin Volcano is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. In addition to the local monitoring network, AVO uses nearby geophysical networks, regional infrasound and lighting data, and satellite images to detect eruptions.
(12) Volcanic cloud height:	At summit (9375 ft)
(13) Other volcanic cloud information:	Evident in ony 1 web cam image from 18:25 UTC
(14) Remarks:	Shishaldin Volcano, located near the center of Unimak Island in the eastern Aleutian Islands, is a spectacular symmetric cone with a base diameter of approximately 10 miles (16 km). A 660 ft. (200 m) wide funnel-shaped summit crater typically emits a steam plume and occasional small amounts of ash. Shishaldin is one of the most active volcanoes in the Aleutian volcanic arc, with at least 54 episodes of unrest including over 26 confirmed eruptions since 1824. Most eruptions are relatively small, although the April-May 1999 event generated an ash column that reached 45,000 ft. (14 km) above sea level.
(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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