September 18, 799 Tsunami: Kashima, Japan
A tsunami of unknown cause began at Kashima, Japan on September 18, 799. The water rose as high as 2 meters. Its effects were recorded at 4 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
- September 18, 799
- Source
- Kashima, Japan
- Cause
- Unknown
- Maximum water height
- 2 m (6.6 ft)
- Runups recorded
- 4
- Tsunami intensity (Soloviev-Imamura)
- 1
- Tsunami magnitude (Iida)
- 1
- Waters
- Ocean
- How certain
- Questionable tsunami
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.
799?, September 18. There were oscillations in sea level, about 2 m high, at Hitachi (Ibaraki Prefecture), on the east of Honshu Island. The same oscillations may have occurred at Nakaminato, Kuji and Kashima. It is possible that this was a tsunami from an earthquake at Sanriku, a remote earthquake or storm waves. (reference #414)
Tsunami hit east coast of Ibaraki Prefecture (Hitachi, Kashima, naka, Kuji, and Taka County). (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 |
|---|---|---|---|---|---|---|---|
| Hitachi | Japan | 2 | Eyewitness observation of water height | ||||
| Nakaminato | Japan | Eyewitness observation of water height | |||||
| Kuji | Japan | Eyewitness observation of water height | |||||
| Kashima | Japan | Eyewitness observation of water height |
More
Every tsunami in 799The 700sTsunamis 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 63.