April 1, 1726 Tsunami: Katsuyama, Japan
A tsunami caused by a magnitude 6.6 earthquake began at Katsuyama, Japan on April 1, 1726. Its effects were recorded at 1 place.
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
- April 1, 1726
- Source
- Katsuyama, Japan
- Cause
- Earthquake
- Earthquake
- Magnitude 6.6
- Runups recorded
- 1
- Tsunami intensity (Soloviev-Imamura)
- 1
- Tsunami magnitude (Iida)
- 1
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 36.300° N, 136.000° E
The toll
- Deaths
- Many (about 101 to 1,000)
- Damage
- Moderate (about $1 to $5 million)
- Houses destroyed
- Some (about 51 to 100)
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.
Houses and fields ruined by tsunami, violent wind and rain with strong earthquake. Many people and animal drownings in gushed mud water like great river. (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 |
|---|---|---|---|---|---|---|---|
| Katsuyama | Japan | 50 | Eyewitness observation of water height |
More
Every tsunami in 1726The 1700sTsunamis 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 399.