November 6, 1971 Tsunami: Rat Islands, Aleutian Islands, AK, United States
A tsunami caused by a magnitude 5.7 earthquake began at Rat Islands, Aleutian Islands, AK, United States on November 6, 1971 at 22:00:00 UTC. The water rose as high as 0.1 meters. Its effects were recorded at 2 places.
Where the waves reached
The source (white) and every runup with a place, colored by the water height recorded there. A ring is a runup NCEI marks doubtful.
- Under 1 m
- 1 to 3 m
- 3 to 10 m
- 10 to 30 m
- 30 m and more
- Height not recorded
The tsunami
- Date
- November 6, 1971, 22:00:00 UTC
- Source
- Rat Islands, Aleutian Islands, AK, United States
- Cause
- Earthquake
- Earthquake
- Magnitude 5.7, 21 km deep
- Maximum water height
- 0.1 m (0.3 ft)
- Runups recorded
- 2
- Waters
- Ocean
- How certain
- Questionable tsunami
- Source location
- 51.500° N, 179.100° E
The toll
The record gives no deaths, injuries or damage for this tsunami.
What the record says
NCEI’s account, from the sources it cites.
This underground nuclear explosion (code-named "Cannikan") generated two small, recorded waves on the north shore of Amchitka. The energy from the explosion appeared to be trapped as edge waves on the shelf, as they were not recorded on the south side of Amchitka, at nearby Rat Island, or on deep ocean gages. It is not known whether the waves were tsunami or seiche. (Ref #239)
Every runup
Nearest the source first. Heights are above sea level at the time; a tide gauge reads half the wave’s full height.
| Where | Country | Km from source | Water height, m | Inland, m | Measured by | First wave, UTC | Deaths |
|---|---|---|---|---|---|---|---|
| Square Bay, Amchitka Island, AK, AK | United States | 9 | 0.1 | Tide gauge (half the maximum wave height) | day 6, 22:10 | ||
| Constantine Harbor, Amchitka, AK, AK | United States | 17 | 0.05 | Tide gauge (half the maximum wave height) | day 6, 22:12 |
More
Every tsunami in 1971The 1900sTsunamis of United StatesThe earthquakeThis day in weather historyAlerts in force
Sources
Tsunami events and runups from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-09-24. NCEI tsunami event 2042.