1946 Aleutian Islands earthquake
People fleeing the approaching tsunami in Hilo, Hawaii | |
Anchorage Juneau Fairbanks Adak White Horse King Salmon Unalaska Anadyr St. Paul Nome | |
| UTC time | 1946-04-01 12:29:01 |
|---|---|
| ISC event | 898313 |
| USGS-ANSS | ComCat |
| Local date | April 1, 1946 |
| Local time | 02:29 |
| Magnitude | 7.4 Ms, 8.6 Mw, 9.3 Mt |
| Depth | 15 km (9.3 mi) |
| Epicenter | 53°29′N 162°50′W / 53.49°N 162.83°W |
| Type | Megathrust |
| Areas affected | Hawaii, Alaska United States |
| Max. intensity | MMI VI (Strong) |
| Tsunami | Up to 42 m (138 ft) at Unimak Island |
| Casualties | 165–173 |
The 1946 Aleutian Islands earthquake occurred near the Aleutian Islands, Alaska on April 1, 1946. The shock measured (Mw) 8.6, Mt 9.3 or (Ms) 7.4. It had a maximum Mercalli intensity of VI (Strong). The seafloor along the fault was elevated, triggering a Pacific-wide tsunami with multiple destructive waves at heights ranging from 45–138 ft (14–42 m), resulting in 165–173 casualties and over US$26 million (equivalent to $429,000,000 in 2025) in damage. The tsunami obliterated the Scotch Cap Lighthouse on Unimak Island, Alaska among others, and killed all five lighthouse keepers. Despite the damage to the Aleutian Island Unimak, the tsunami had an almost imperceptible effect on the Alaskan mainland.