Quite an impressive event, and thankfully, no one was harmed. And it's probably a good reminder of why ongoing work to better understand and track these events matters!
And thanks to @geophysichick.bsky.social for letting all of us know about the event!

(3) There was a seiche that lasted roughly an hour after the slide, similar to past events like the 2023 Greenland landslide and tsunami.

Here's our story about this event, likely to evolve in the upcoming days: earthquake.alaska.edu/major-landsl...

(2) We saw remarkable precursor activity starting ~18 hours before the main slide. These smaller events came from the same area, which might be one of the best examples of landslide precursors that have ever been recorded.

A day later, the confirmed location came pointing to the glacier's terminus. Three things really stand out.

(1) The seismic signal was recorded more than 1,000 km away, and even the high-frequency moveout could be tracked statewide—clear signs of a big landslide.

The location pointed to ~7 km east of South Sawyer Glacier, and we got a rather large volume estimate -- range of 30 - 290 million cubic meters. That’s bigger than anything we’ve used to build our size-estimation method, so there’s a lot of uncertainty.

Quite an impressive event, and thankfully, no one was harmed. And it's probably a good reminder of why we should continue researching and monitoring these kinds of emerging hazards!

(3) The slide set off a seiche that lasted around 5 hours, similar to events like the 2023 Greenland landslide & tsunami.
Here's our story about this event, likely to evolve in the upcoming days: earthquake.alaska.edu/major-landsl...

(2) We saw remarkable precursor activity starting ~18 hours before the main slide. These smaller events came from the same area, which might be one of the best examples of landslide precursors that have ever been recorded.

A day later, the confirmed location came pointing to the glacier's terminus. Three things really stand out.

(1) The seismic signal was recorded more than 1,000 km away, and even the high-frequency moveout could be tracked statewide—clear signs of a big landslide.

The location pointed to ~7 km east of South Sawyer Glacier, and we got a rather large volume estimate -- range of 30 - 290 million cubic meters. That’s bigger than anything we’ve used to build our size-estimation method, so there’s a lot of uncertainty.

Just five months earlier, we stood at this very site with 300 others during the 2024 SSA field trip. There were no visible signs of instability. This event illustrates how suddenly these failures can occur, and why real-time, regional monitoring is crucial for coastal Alaska.
doi.org/10.1029/2025...

There’s more: the largest of the three landslides triggered a modest tsunami — a 4 cm wave recorded at a nearby tide gauge.

To our knowledge, this is the first time a landslide in this region has been detected in real time and confirmed to have generated a tsunami.