March 20, 1960 Tsunami: Sanriku, Japan
A tsunami caused by a magnitude 7.5 earthquake began at Sanriku, Japan on March 20, 1960 at 17:07:30 UTC. The water rose as high as 1 meters. Its effects were recorded at 19 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
- March 20, 1960, 17:07:30 UTC
- Source
- Sanriku, Japan
- Cause
- Earthquake
- Earthquake
- Magnitude 7.5, 20 km deep
- Maximum water height
- 1 m (3.3 ft)
- Runups recorded
- 19
- Tsunami intensity (Soloviev-Imamura)
- -2
- Tsunami magnitude (Iida)
- 0
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 39.800° N, 143.400° E
The toll
- Damage
- Limited (under about $1 million) with the earthquake or eruption that caused it
Where the literature gives no number, NCEI records a description on a scale of 1 to 4, printed here in its words. Damage is in millions of US dollars of the year of the event, not adjusted for inflation.
What the record says
NCEI’s account, from the sources it cites.
March 21, 1960, 2:07 local time, March 20 17:07 UTC, 39.8 N, 143.5 E, 20 km depth, magnitude 7.5). An earthquake with source 120 km long off the coast of Iwate Prefecture caused slight destruction. A weak tsunami arose, which was registered by tide gauges. (reference #414)
March 21, 1960, 02:07 (local time). 39.8 N, 143.4 E, magnitude 7.5. Onagawa l m (amplitude). Hachinohe 1cm, Miyako 33cm, Ayukawa 42cm, Onahama 51cm, Kushiro trace,
Kamaishi 30cm (peak-trough). (reference #150)
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 |
|---|---|---|---|---|---|---|---|
| Omoto | Japan | 121 | 0.4 | Eyewitness observation of water height | |||
| Taro (Tarocho) | Japan | 122 | 0.5 | Eyewitness observation of water height | |||
| Miyako | Japan | 123 | 0.17 | Tide gauge (half the maximum wave height) | day 20, 17:29 | ||
| Tsugaruishi | Japan | 127 | 0.3 | Eyewitness observation of water height | |||
| Orikasa | Japan | 129 | 0.3 | Eyewitness observation of water height | |||
| Otsuchi | Japan | 137 | 0.4 | Eyewitness observation of water height | |||
| Ryoishi | Japan | 140 | 0.63 | Eyewitness observation of water height | |||
| Kamaishi | Japan | 143 | 0.15 | Tide gauge (half the maximum wave height) | day 20, 17:33 | ||
| Hachinohe | Japan | 179 | 0.41 | Tide gauge (half the maximum wave height) | day 20, 17:50 | ||
| Enoshima | Japan | 220 | 0.05 | Tide gauge (half the maximum wave height) | day 20, 17:47 | ||
| Onagawa | Japan | 227 | 1 | Eyewitness observation of water height | day 20, 17:53 | ||
| Ayukawa | Japan | 234 | 0.21 | Tide gauge (half the maximum wave height) | day 20, 17:51 | ||
| Urakawa | Japan | 268 | 0.2 | Tide gauge (half the maximum wave height) | |||
| Hakodate | Japan | 311 | 0.17 | Tide gauge (half the maximum wave height) | |||
| Moriko | Japan | 348 | 0.08 | Tide gauge (half the maximum wave height) | |||
| Muroran | Japan | 350 | 0.1 | Tide gauge (half the maximum wave height) | day 20, 18:21 | ||
| Kushiro | Japan | 362 | 0.1 | Tide gauge (half the maximum wave height) | day 20, 17:53 | ||
| Onahama | Japan | 386 | 0.26 | Tide gauge (half the maximum wave height) | day 20, 18:07 | ||
| Hanasaki | Japan | 427 | 0.09 | Tide gauge (half the maximum wave height) |
More
Every tsunami in 1960The 1900sTsunamis of JapanThe 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 1898.