A 481-meter-high landslide-tsunami in a cruise ship–frequented Alaska fjord
- Dan H. Shugar
- Katherine R. Barnhart
- Mira Berdahl
- Jacqueline Caplan-Auerbach
- Göran Ekström
- Aram Fathian
- Marten Geertsema
- Stephen P. Hicks
- Bretwood Higman
- Erin K. Jensen
- Ezgi Karasözen
- Patrick Lynett
- John Lyons
- Thomas Monahan
- Gerard Roe
- Kristian Svennevig
- Liam Toney
- Maximillian Van Wyk de Vries
- Michael E. West
2026-05-06
Early in the morning of 10 August 2025, a >64 × 10 6 m 3 landslide struck Tracy Arm fjord in Alaska. The landslide was preconditioned by glacial retreat caused by climate change. The resulting 481 m runup megatsunami followed an initial 100-m-high breaking wave traveling >70 m s −1 . The landslide was preceded by several days of microseismicity, which increased in rate and magnitude until ~1 hour before failure. The landslide produced globally observed long-period seismic waves equivalent in size to a M5.4 earthquake. A long-period (~66 s) global seismic signal, produced by a landslide-induced seiche trapped within the fjord, persisted for up to 36 hours, the second time a days-long seiche has been thus observed. With fjord regions increasingly visited by cruise ships, and climate change making similar events more likely, this unanticipated, near-miss event highlights the growing risk from landslides and tsunamis in coastal environments.