Overview
- The team reconstructed a landslide-driven tsunami in Tracy Arm fjord, which struck on August 10, 2025, and reached a maximum run-up of 481 meters.
- Roughly 64 million cubic meters of rock collapsed into the fjord, generating long-period seismic waves equivalent to a magnitude 5.4 earthquake.
- The slide and the wave set off a seiche that kept water sloshing in the fjord for more than 24 hours, with vibrations detectable at regional to global scales.
- Satellite and aerial images show a bright landslide scar, a ring of flattened forest along the fjord, and near-total stripping of vegetation on Sawyer Island about 9 kilometers away.
- Researchers call the event a near miss for cruise and tour traffic and propose automated searches for narrowband seismic signals to enable early warning in glaciated fjords.