March 9, 1931 Tsunami: Sanriku, Japan
A tsunami caused by a magnitude 7.6 earthquake began at Sanriku, Japan on March 9, 1931 at 03:49:00 UTC. The water rose as high as 0.4 meters. Its effects were recorded at 7 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 9, 1931, 03:49:00 UTC
- Source
- Sanriku, Japan
- Cause
- Earthquake
- Earthquake
- Magnitude 7.6, 60 km deep
- Maximum water height
- 0.4 m (1.3 ft)
- Runups recorded
- 7
- Tsunami intensity (Soloviev-Imamura)
- -1
- Tsunami magnitude (Iida)
- -1.3
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 41.200° N, 142.500° 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.
Reference #414:
1931, March 9, 12:49 local time. There was an earthquake with source at sea to the east of Aomori Prefecture. It was felt on most of Hokkaido Island, in Tohoku and Kanto regions, even as far as Kofu (Yamanashi Prefecture) and Hikone (Shiga Prefecture). There was minor destruction at Hakodate. It was followed by aftershocks.
A weak tsunami was registered after the earthquake.
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 |
|---|---|---|---|---|---|---|---|
| Hachinohe | Japan | 110 | 0.2 | Tide gauge (half the maximum wave height) | day 9, 04:43 | ||
| Miyako | Japan | 178 | Tide gauge (half the maximum wave height) | ||||
| Tsukihama | Japan | 306 | 0.09 | Tide gauge (half the maximum wave height) | day 9, 05:37 | ||
| Ishinomaki | Japan | 327 | 0.07 | Tide gauge (half the maximum wave height) | day 9, 05:36 | ||
| Ayukawa | Japan | 333 | Tide gauge (half the maximum wave height) | day 9, 05:00 | |||
| Oshima (Shiogamako) | Japan | 347 | 0.03 | Tide gauge (half the maximum wave height) | day 9, 05:35 | ||
| Onahama | Japan | 494 | 0.04 | Tide gauge (half the maximum wave height) | day 9, 05:43 |
More
Every tsunami in 1931The 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 1639.