August 12, 1956 Tsunami: Izu Peninsula, Japan
A tsunami caused by a magnitude 6.5 earthquake began at Izu Peninsula, Japan on August 12, 1956 at 16:59:37 UTC. 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
- August 12, 1956, 16:59:37 UTC
- Source
- Izu Peninsula, Japan
- Cause
- Earthquake
- Earthquake
- Magnitude 6.5, 50 km deep
- Runups recorded
- 1
- Tsunami intensity (Soloviev-Imamura)
- -1
- Tsunami magnitude (Iida)
- -1
- Waters
- Ocean
- How certain
- Erroneous entry
- Source location
- 33.800° N, 138.800° 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.
August 13, 1:59 [local time], 1956, event validity erroneous. There was an earthquake with source off the Izu Peninsula. A very weak tsunami was reported, but these data were not confirmed later. (reference #414)
Aug 13, 1956, 16:59 UTC, event validity 4. 33.8 N, 138.8 E, magnitude 6.5. (reference #79)
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 |
|---|---|---|---|---|---|---|---|
| Yaene, Hachijo Island | Japan | 119 | 0.23 | Tide gauge (half the maximum wave height) |
More
Every tsunami in 1956The 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 1863.