1957 Andreanof Islands earthquake
| UTC time | 1957-03-09 14:22:33 |
|---|---|
| ISC event | 886030 |
| USGS-ANSS | ComCat |
| Local date | March 9, 1957 |
| Local time | 04:22:33 |
| Magnitude | 8.6 Mw 8.1–8.3 Ms 9.0 Mt |
| Depth | 25 km (16 mi) |
| Epicenter | 51°30′N 175°38′W / 51.5°N 175.63°W |
| Fault | Aleutian Trench |
| Type | Megathrust |
| Areas affected | Aleutian Islands & Hawaii |
| Total damage | $5 million |
| Max. intensity | MMI VIII (Severe) |
| Tsunami | 23 m (75 ft) |
| Casualties | 2 dead (indirect) |
The 1957 Andreanof Islands earthquake occurred at 04:22 local time on March 9 with a moment magnitude estimated at 8.6 and a maximum Modified Mercalli intensity of VIII (Severe). It occurred south of the Andreanof Islands group, which is part of the Aleutian Islands arc. The event occurred along the Aleutian Trench, the convergent plate boundary that separates the Pacific plate and the North American plates near Alaska. A basin-wide tsunami followed, with effects felt in Alaska and Hawaii, and strong waves recorded across the Pacific rim. Total losses were around $5 million (equivalent to $55,977,488 in 2024).