Historical tsunamis · Aug 2, 1971, 7:24 AM UTC
1971 Japan Trench tsunami
Japan
The tsunami of Aug 2, 1971, 7:24 AM UTC originated near Japan Trench (Japan).
Key facts
- Date
- Aug 2, 1971, 7:24 AM UTC
- Cause
- Earthquake
- Magnitude
- M7.3
- Depth
- 51 km
- Maximum documented water height
- 0.51 m
- Damage
- limited (under US$ 1 million)
- Observation records
- 17
- Countries affected
- 1
It was triggered by a magnitude 7.3 earthquake at a depth of 51 km.
The highest documented water height was 0.51 m (Shoyagyoko, Japan).
17 observation sites in 1 countries are recorded.
Damage is estimated at limited (under US$ 1 million).
Map of observation sites
17Each dot is a documented observation site; colour and size show the observed water height. The triangle marks the source.
Observations by country
| Country | Observation records | Maximum documented water height | Deaths | Earliest arrival |
|---|---|---|---|---|
| Japan | 17 | 0.51 m Shoyagyoko | — | — |
Highest documented water heights
15 / 17Individual documented observations for this event. Heights come from different measurement types and sources; not every location has a measured height.
| Location / station | Observed height | Distance from source | Country |
|---|---|---|---|
| Shoyagyoko · Hokkaido | 0.51 m | 72 km | Japan |
| Hiroo · Hokkaido | 0.20 m | 99 km | Japan |
| Tokachiko · Hokkaido | 0.15 m | 101 km | Japan |
| Urakawa · Hokkaido | 0.12 m | 105 km | Japan |
| Samani · Hokkaido | 0.11 m | 92 km | Japan |
| Kushiro · Hokkaido | 0.10 m | 189 km | Japan |
| Hachinohe (Kensetsukyoku) · Aomori | 0.09 m | 194 km | Japan |
| Hachinohe · Aomori | 0.08 m | 192 km | Japan |
| Hanasaki · Hokkaido | 0.08 m | 269 km | Japan |
| Hakodate · Hokkaido | 0.07 m | 234 km | Japan |
| Ofunato · Iwate | 0.07 m | 304 km | Japan |
| Tomakomainishiko · Hokkaido | 0.06 m | 208 km | Japan |
| Ayukawa · Miyagi | 0.05 m | 384 km | Japan |
| Miyako · Iwate | 0.05 m | 233 km | Japan |
| Muroran · Hokkaido | 0.05 m | 236 km | Japan |
More tsunamis
Source: NOAA National Centers for Environmental Information (NCEI), Global Historical Tsunami Database. Confirmed events only. Deaths and damage are database estimates; older records are incomplete. Water heights come from different types of observation.