1958 Lituya Bay earthquake and megatsunami
| UTC time | 1958-07-10 06:15:58 |
|---|---|
| ISC event | 884702 |
| USGS-ANSS | ComCat |
| Local date | July 9, 1958 |
| Local time | 22:15 PST |
| Magnitude | 7.8–8.3 Mw |
| Depth | 35 km (22 mi) |
| Epicenter | 58°22′12″N 136°39′54″W / 58.370°N 136.665°W |
| Fault | Fairweather Fault |
| Type | Strike-slip |
| Areas affected | Lituya Bay, Alaska |
| Max. intensity | MMI XI (Extreme) |
| Tsunami | 524 m (1,719 ft) runup |
| Casualties | 5 dead |
The 1958 Lituya Bay earthquake occurred on July 9, 1958, at 22:15:58 PST with a moment magnitude of 7.8 to 8.3 and a maximum Mercalli intensity of XI (Extreme). The strike-slip earthquake took place on the Fairweather Fault and triggered a rockslide of 30 million cubic meters (40 million cubic yards) and about 90 million tons into the narrow inlet of Lituya Bay, Alaska. The impact was heard 80 kilometers (50 mi) away, and the sudden displacement of water resulted in a megatsunami that washed out trees to a maximum elevation of 524 meters (1,719 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.