Over the past several months, signs of volcanic unrest at Shishaldin Volcano have been declining. Slightly elevated seismicity, small infrasound signals and weak gas emissions continue to be detected but there is no indication of explosive activity or the presence of lava in the crater. This level of activity is expected to persist and continue to wane as the volcano settles after the eruption that began in July 2023 and continued until November 2023. The volcano appears to have returned to a background condition and poses no immediate threat of eruptive activity. Accordingly, AVO is lowering the Aviation Color Code to GREEN and the Volcano Alert Code to NORMAL. Resumption of volcanic activity would likely be preceded by increased seismicity, infrasound, elevated temperatures, and gas 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 monitor the volcano.
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 activity during July–November, 2023 generated ash columns that reached between 30,000 ft (9 km) and 42,000 ft (13 km) above sea level.
Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497
David Fee, Coordinating Scientist, UAF 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: | (20240830/1700Z) |
| (3) Volcano: | Shishaldin (VNUM #311360) |
| (4) Current Color Code: | GREEN |
| (5) Previous Color Code: | YELLOW |
| (6) Source: | Alaska Volcano Observatory |
| (7) Notice Number: | 2024/A621 |
| (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: |
Over the past several months, signs of volcanic unrest at Shishaldin Volcano have been declining. Slightly elevated seismicity, small infrasound signals and weak gas emissions continue to be detected but there is no indication of explosive activity or the presence of lava in the crater. This level of activity is expected to persist and continue to wane as the volcano settles after the eruption that began in July 2023 and continued until November 2023. The volcano appears to have returned to a background condition and poses no immediate threat of eruptive activity. Accordingly, AVO is lowering the Aviation Color Code to GREEN and the Volcano Alert Code to NORMAL. Resumption of volcanic activity would likely be preceded by increased seismicity, infrasound, elevated temperatures, and gas 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 monitor the volcano. |
| (12) Volcanic cloud height: | none |
| (13) Other volcanic cloud information: | none |
| (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 activity during July–November, 2023 generated ash columns that reached between 30,000 ft (9 km) and 42,000 ft (13 km) above sea level. |
| (15) Contacts: | Matt Haney, Scientist-in-Charge, USGS mhaney@usgs.gov (907) 786-7497 David Fee, Coordinating Scientist, UAF dfee1@alaska.edu (907) 378-5460 |
| (16) Next Notice: | |