Tanaga unrest 2023
Start: March 7, 2023 [1]
Stop: July 18, 2023 [1]
Event Type: Not an eruption
Description: On Tuesday, March, 7, 2023, AVO elevated the Aviation Color Code and Volcano Alert Level at Tanaga to YELLOW/ADVISORY, stating "earthquake activity beneath Tanaga Volcano began to increase slowly starting at about 1:30 pm AKST today. At roughly 8:45 pm AKST this evening, the activity escalated with earthquakes occurring as often as 2 or 3 each minute. Initial locations of these earthquakes place them at shallow depths beneath the summit of Tanaga Volcano, and the largest of these earthquakes have magnitudes between 2 and 3."
On Thursday, March 9, 2023, AVO elevated Tanaga again to ORANGE/WATCH, stating "Over the past 24 hours, earthquake activity near Tanaga Volcano has been elevated and continues. This sustained activity indicates an increased potential for eruption at the volcano.*** Seismic activity is also elevated at Takawangha volcano, which is about 8 km (5 mi) east of Tanaga on Tanaga Island. If an eruption were to occur, it is uncertain at this stage if it would come from Tanaga or Takawangha."
On Thursday, March 9, 2023, AVO elevated Tanaga again to ORANGE/WATCH, stating "Over the past 24 hours, earthquake activity near Tanaga Volcano has been elevated and continues. This sustained activity indicates an increased potential for eruption at the volcano.*** Seismic activity is also elevated at Takawangha volcano, which is about 8 km (5 mi) east of Tanaga on Tanaga Island. If an eruption were to occur, it is uncertain at this stage if it would come from Tanaga or Takawangha."
Images
References Cited
[1] Alaska Volcano Observatory website, 2005
Alaska Volcano Observatory, 2005-, Alaska Volcano Observatory website: http://www.avo.alaska.edu.Complete Eruption References
Alaska Volcano Observatory website, 2005
Alaska Volcano Observatory, 2005-, Alaska Volcano Observatory website: http://www.avo.alaska.edu.
Alaska Earthquake Center Quarterly Technical Report, July–September 2023, 2023
Ruppert, N.A., Farrell, A., Grassi, B., Holtkamp, S.G., Low, G., McFarlin, H., Nadin, E., Parcheta, C., West, M.E., and Wiser, S., 2023, Alaska Earthquake Center Quarterly Technical Report, July–September 2023: Alaska Earthquake Center Quarterly Technical Report 2023-Q3, 52 p.

Detection and analysis of Aleutian Arc seismicity (2022-2023) using an autonomous hydrophone array, 2025
Ingale, V.V., Tepp, G., Dziak, R.P., and Parnell-Turner, R., 2025, Detection and analysis of Aleutian Arc seismicity (2022-2023) using an autonomous hydrophone array: Geochemistry, Geophysics, Geosystems v. 26, no. 8, e2025GC012320. https://doi.org/10.1029/2025GC012320

