The Alaska bay where a 524-meter megatsunami occurred in 1958 is Lituya Bay. The extraordinary wave was triggered when the July 9 earthquake sent an enormous rockslide into the bay’s narrow, fjord-like waters.
The earthquake struck on the Fairweather Fault and had an estimated moment magnitude between 7.8 and 8.3. About 30 million cubic meters of rock plunged from the mountainside into Gilbert Inlet, displacing water with such force that it stripped trees from slopes up to 524 meters above sea level.
That measurement is a run-up height, not a 524-meter wall of water traveling across the open ocean. Lituya Bay’s steep sides and restricted entrance focused the energy, creating an unusually high local wave. The event killed five people, although several fishing boats were caught in the surge and one was carried over a wave.
Lituya Bay had experienced other large waves before 1958, including events in 1854, 1899, and 1936. The disaster helped scientists recognize landslides and rockfalls as causes of megatsunamis.