USGS Volcano Notice for Aviation - DOI-USGS-AVO-2023-07-15T20:56:08-08:00

(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20230716/0552Z)
(3) Volcano:	Shishaldin (VNUM #311360)
(4) Current Color Code:	ORANGE
(5) Previous Color Code:	ORANGE
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2023/A1065
(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:	The eruption of Shishaldin Volcano has intensified. An ash cloud to 15,000 ft (4.6 km) above sea level and drifting to the SSE has been observed in satellite data starting at about 9:00 pm AKDT (17:00 UTC). The National Weather Service has issued a SIGMET for this activty. Seismic tremor amplitudes began to increase starting around 5:00 pm AKDT (1:00 UTC) and are continuing. The actvity has also been observed on regional infrasound (presure sensor) arrays. Eruptions from Shishaldin have produced minor and on occasion significant ash clouds in the past. These can occur with little warning. Shishaldin is monitored by local seismic and infrasound sensors, web cameras, and a telemetered geodetic network. The local monitoring network is partially impaired, therefore AVO is also using nearby geophysical networks, satellite data and regional infrasound and lighting data to detect activity. AVO will continue to closely monitor unrest at Shishaldin Volcano.
(12) Volcanic cloud height:	15,000 feet above sea level
(13) Other volcanic cloud information:	Drifting to the SSE
(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 16 km (10 mi). A 200-m-wide (660 ft) 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 above sea level.
(15) Contacts:	Kristi Wallace, Acting Scientist-in-Charge, USGS kwallace@usgs.gov (907) 786-7497 Pavel Izbekov, Acting Coordinating Scientist, UAFGI peizbekov@alaska.edu (907) 378-5460
(16) Next Notice: