Video showing six hours of seismic data from seismic station TANO on Tanaga Volcano. The top panel shows the spectrogram, and below is the seismic data. The audio is the subaudible seismic signal mapped to the range of human hearing. Earthquakes are heard as "pops" and occur frequently during this time period. A lower frequency event is heard around 13:51 UTC (04:51 AK). Video created by David Fee and Liam Toney, UAFGI/AVO. To view video, click the "full res" link below to download the file.
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."