August 6, 1984 Tsunami: Kyushu, Japan
A tsunami caused by a magnitude 7 earthquake began at Kyushu, Japan on August 6, 1984 at 19:06:38 UTC. The water rose as high as 0.2 meters. Its effects were recorded at 6 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
- August 6, 1984, 19:06:38 UTC
- Source
- Kyushu, Japan
- Cause
- Earthquake
- Earthquake
- Magnitude 7, 46 km deep
- Maximum water height
- 0.2 m (0.7 ft)
- Runups recorded
- 6
- Tsunami magnitude (Iida)
- -2.3
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 32.386° N, 131.945° E
The toll
- Injuries
- 9 with the earthquake or eruption that caused it
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.
A magnitude 6.7 Ms earthquake at 19:07 UT at Kyushu, Japan injured 9 people and caused damage IV (JMA), also measured onSW Shikoku.
32.3,132.2,7.2TW
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 |
|---|---|---|---|---|---|---|---|
| Hyuga-Shirahama | Japan | 27 | 0.14 | Tide gauge (half the maximum wave height) | |||
| Nobeoka | Japan | 35 | 0.2 | ||||
| Tosa-Shimizu | Japan | 105 | 0.13 | Tide gauge (half the maximum wave height) | |||
| Kochi | Japan | 198 | 0.04 | Tide gauge (half the maximum wave height) | |||
| Murotomisaki | Japan | 230 | 0.12 | Tide gauge (half the maximum wave height) | |||
| Owase | Japan | 439 | 0.03 | Tide gauge (half the maximum wave height) |
More
Every tsunami in 1984The 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 2155.