July 20, 1850 Tsunami: Sanriku, Japan
A tsunami caused by a landslide began at Sanriku, Japan on July 20, 1850. The water rose as high as 2 meters.
Where the waves reached
The source of the tsunami. No runup with a place is recorded for it.
- 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
- July 20, 1850
- Source
- Sanriku, Japan
- Cause
- Landslide
- Maximum water height
- 2 m (6.6 ft)
- Runups recorded
- 0
- Tsunami intensity (Soloviev-Imamura)
- 0
- Tsunami magnitude (Iida)
- 1
- Waters
- Ocean
- How certain
- Very doubtful tsunami
- Source location
- 39.500° N, 142.000° 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 #150:
1850, July 20. Epicenter: Sanriku. 39.5 N, 142.0 E. Landslide at Rikuchu, Iwate Pref. Tsunami magnitude: 1, validity 2.
Reference #79:
1850, July 20. Rikuchu, Japan. Reports of great sounds and tsunami. Musya (1951) regards as very doubtful.
Reference #414:
1859, [must be a typo, 1850 is the true date], July 20. There was a loud noise and a tsunami on the coast of Iwate Prefecture. The data are very doubtful. Validity 1.
More
Every tsunami in 1850The 1800sTsunamis of JapanThis 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 774.