April 17, 1948 Tsunami: Tokaido, Japan
A tsunami caused by a magnitude 7.2 earthquake began at Tokaido, Japan on April 17, 1948 at 16:11:00 UTC. The water rose as high as 0.6 meters. Its effects were recorded at 3 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
- April 17, 1948, 16:11:00 UTC
- Source
- Tokaido, Japan
- Cause
- Earthquake
- Earthquake
- Magnitude 7.2, 40 km deep
- Maximum water height
- 0.6 m (2.0 ft)
- Runups recorded
- 3
- Tsunami intensity (Soloviev-Imamura)
- -1
- Tsunami magnitude (Iida)
- -0.7
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 33.100° N, 135.600° 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.
Aftershock of previous event.
Reference #414:
1948, April 18, 1:11 local time. There was an earthquake in the region of the Kii Peninsula. A tsunami 50 cm high was registered at Inami (Wakayama Prefecture). It was 33 cm high at Kushimoto. The assumed travel time of the tsunami was 12 minutes to Kushimoto and 28 minutes to Owase.
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 |
|---|---|---|---|---|---|---|---|
| Kushimoto | Japan | 44 | 0.17 | Tide gauge (half the maximum wave height) | |||
| Inami | Japan | 87 | 0.6 | Eyewitness observation of water height | |||
| Tosa-Shimizu | Japan | 250 | 0.1 | Tide gauge (half the maximum wave height) |
More
Every tsunami in 1948The 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 1781.