The 1958 Lituya Bay earthquake occurred on July 9 at 22:15:58 with a moment magnitude of 7.8 to 8.3 and a maximum Mercalli intensity of XI. The strike-slip earthquake took place on the Fairweather Fault and triggered a rockslide of 40 million cubic yards into the narrow inlet of Lituya Bay, Alaska. The impact was heard 50 miles away, and the sudden displacement of water resulted in a megatsunami that washed out trees to a maximum elevation of 1,720 feet at the entrance of Gilbert Inlet. This is the largest and most significant megatsunami in modern times; it forced a re-evaluation of large-wave events and the recognition of impact events, rockfalls, and landslides as causes of very large waves.