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USGS Volcano Notice - DOI-USGS-AVO-2023-10-03T06:01:15-08:00
Volcano: Shishaldin (VNUM #311360)
Current Volcano Alert Level: WARNING
Previous Volcano Alert Level: WATCH
Current Aviation Color Code: RED
Previous Aviation Color Code: ORANGE
Issued: Tuesday, October 3, 2023, 6:12 AM AKDT
Source: Alaska Volcano Observatory
Notice Number: 2023/A1461
Location: N 54 deg 45 min W 163 deg 58 min
Elevation: 9373 ft (2857 m)
Area: Aleutians
Volcanic Activity Summary:
An ash cloud from Shishaldin Volcano reaching 40,000 ft (12 km) above sea level was observed in satellite data at 5:20 am AKDT (13:50 UTC). This follows a several-hour increase in observed eruptive activity, and a recent sharp increase in infrasound, seismicity, and lighting detections. In response, the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The National Weather Service has issued a SIGMET for this ash cloud. Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.
Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano.
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] Over 40,000 ft (12 km) above sea level
[Other volcanic cloud information] Ash plume is drifting south
Hazard Analysis:
[Pyroclastic flow] likely on the immediate flanks of the volcano
[Mud flow] likely 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: | (20231003/1412Z) |
(3) Volcano: | Shishaldin (VNUM #311360) |
(4) Current Color Code: | RED |
(5) Previous Color Code: | ORANGE |
(6) Source: | Alaska Volcano Observatory |
(7) Notice Number: | 2023/A1461 |
(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: |
An ash cloud from Shishaldin Volcano reaching 40,000 ft (12 km) above sea level was observed in satellite data at 5:20 am AKDT (13:50 UTC). This follows a several-hour increase in observed eruptive activity, and a recent sharp increase in infrasound, seismicity, and lighting detections. In response, the Aviation Color Code is being raised to RED and the Volcano Alert Level is being raised to WARNING. The National Weather Service has issued a SIGMET for this ash cloud. Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano. Based on previous eruption cycles, significant ash emissions are likely to continue for several hours. Pyroclastic and mudflows are likely on the immediate flanks of the volcano. 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: | Over 40,000 ft (12 km) above sea level |
(13) Other volcanic cloud information: | Ash plume is drifting south |
(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: |