USGS Volcano Notice - DOI-USGS-AVO-2023-10-03T10:04:41-08:00

AVO/USGS Volcanic Activity Notice

Volcano: Shishaldin (VNUM #311360)

Current Volcano Alert Level: WATCH
Previous Volcano Alert Level: WARNING

Current Aviation Color Code: ORANGE
Previous Aviation Color Code: RED


Issued: Tuesday, October 3, 2023, 10:36 AM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2023/A1463
Location: N 54 deg 45 min W 163 deg 58 min
Elevation: 9373 ft (2857 m)
Area: Aleutians

Volcanic Activity Summary:

The explosive ash eruption of Shishaldin Volcano that started this morning at 5:50 AKDT (13:50 UTC) has ended. Clear webcam views show steaming at the volcano's summit. The Aviation Color Code is being lowered to ORANGE and the Volcano Alert Level to WATCH. 

Seismic and infrasound activity are diminished but still slightly above background. Volcanic flows on the flanks of the volcano may create lower-level ash emissions. 

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.

Recent Observations:
[Volcanic cloud height] none observed; low-level ash may be produced from volcanic flows
[Other volcanic cloud information] Unknown

Hazard Analysis:
[Pyroclastic flow] possible on the immediate flanks of the volcano
[Mud flow] possible on the immediate flanks of the volcano

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.

Contacts:

Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460

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.

(1) VOLCANO OBSERVATORY NOTICE FOR AVIATION (VONA)
(2) Issued:	(20231003/1836Z)
(3) Volcano:	Shishaldin (VNUM #311360)
(4) Current Color Code:	ORANGE
(5) Previous Color Code:	RED
(6) Source:	Alaska Volcano Observatory
(7) Notice Number:	2023/A1463
(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 explosive ash eruption of Shishaldin Volcano that started this morning at 5:50 AKDT (13:50 UTC) has ended. Clear webcam views show steaming at the volcano's summit. The Aviation Color Code is being lowered to ORANGE and the Volcano Alert Level to WATCH.  Seismic and infrasound activity are diminished but still slightly above background. Volcanic flows on the flanks of the volcano may create lower-level ash emissions.  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:	none observed; low-level ash may be produced from volcanic flows
(13) Other volcanic cloud information:	Unknown
(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 David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 378-5460
(16) Next Notice: