The location of this major event has now been identified. It was a major rock slope failure that ran out across the South Sawyer Glacier.
The Alaska Earthquake Center has now provided a detailed update about the 10 August 2025 landslide that occurred in the area of Tracy Arm. This work has been led by Ezgi Karasözen, one of the Earthquake Center’s research scientists, so the credit must go to them.
They have posted a very informative page that describes the seismic detection of the landslide, provides eyewitness accounts of the damage that it caused and outlines how they have gone about finding the landslide. This is unusually good public communication about a large event – so well done to them.
They have also published some imagery from their initial reconnaissance of the landslide. Meanwhile, they have also posted to Facebook a short video of the landslide itself – WordPress won’t allow me to embed this, so this is the link:-
https://www.facebook.com/reel/2164841844024421
The footage was captured by LT Chip Baucom and CDR PJ Johansen of the U.S. Coast Guard. There are two stills that are very helpful in providing an initial view of this landslide. First, this is view of the scar and the deposit – note that the landslide has failed onto the South Sawyer Glacier.
This appears to be a large, joint-controlled rock slope failure, with the appearance of a wedge (or several wedges, perhaps).
Second, the video captures the track of the landslide down the glacier towards the fjord:-
This appears to have been a landslide with high mobility – probably the consequence of a large volume and the movement over a low friction surface (ice).
The Alaska Earthquake Center highlights that the seismic instruments detected about 100 small events in the hours leading up to the final collapse. This will be a rich dataset to understand the failure process.
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