Historic Tsunami

1946 United States of America Tsunami

1 April 1946 · Unimak Island, Ak · United States of America

On 1 April 1946 at 12:29 UTC, a tsunami formed near Unimak Island, Ak, United States of America. It was caused by an earthquake and landslide. Waves reached up to 42.0 m high. It was observed at 621 locations in 11 countries or territories, up to 12,954 km from its source. It killed at least 168 people. It is the 31st highest of the tsunamis recorded since 1900.

Date

1 April 1946

Time

12:29 UTC

Cause

Earthquake and landslide

Earthquake Magnitude

8.6

Highest Wave

42.0 m

Observation Sites

621

Furthest Reach

12,954 km

Deaths

168

Estimated Damage

26 million US dollars

Source Country

United States of America

Triggering Earthquake

1946 Aleutian Islands Earthquake

Countries and Territories Reached

Number of observations, highest wave and deaths in each country.

• 520United States of America · 42.2 m164 deaths
• 59French Polynesia · 20.0 m3 deaths
• 5Peru · 0.8 m1 deaths
• 6Chile · 8.6 m
• 1Uk Territory · 5.0 m
• 14New Zealand · 2.4 m
• 2Samoa · 1.2 m
• 10Japan · 0.6 m
• 2Canada · 0.3 m
• 1Australia · 0.1 m
• 1Cook Islands

Highest Waves

• 42.2 mScotch Cap, Unimak Is, Ak · United States of America · 161 km
• 42.0 mScotch Cap, Ak · United States of America · 161 km
• 41.6 mN Cape Lutke, Unimak Is, Ak · United States of America · 150 km
• 39.8 mScotch Cap, Unimak Is, Ak · United States of America · 161 km
• 35.1 mUnimak Island, Ak · United States of America · 167 km5 deaths
• 34.8 mPromontory Hill, Unimak Is, Ak · United States of America · 151 km
• 27.2 mSeal Cape, Unimak Is, Ak · United States of America · 156 km
• 24.6 mLong Is (Northwest) · United States of America · 103 km
• 23.5 mNe Arch Point, Unimak Is, Ak · United States of America · 152 km
• 20.0 mHaakuti, Ua Pou, Marquesas Is. · French Polynesia · 7,290 km

Other Major Tsunamis in the Region

• 2023Sand Point, Ak, United States of America · 0.2 m1 deaths

Sources: NOAA National Centers for Environmental Information, Global Historical Tsunami Database (doi:10.7289/V5PN93H7) · Natural Earth