Historical tsunamis · Dec 20, 1946, 7:19 PM UTC
1946 Honshu: S Coast tsunami
Japan
The tsunami of Dec 20, 1946, 7:19 PM UTC originated near Honshu: S Coast (Japan).
Key facts
- Date
- Dec 20, 1946, 7:19 PM UTC
- Cause
- Earthquake
- Magnitude
- M8.3
- Depth
- 15 km
- Maximum documented water height
- 6.60 m
- Deaths
- 1,362
- Houses destroyed
- 11,661
- Damage
- extreme (over US$ 25 million)
- Observation records
- 253
- Countries affected
- 3
It was triggered by a magnitude 8.3 earthquake at a depth of 15 km.
The highest documented water height was 6.60 m.
253 observation sites in 3 countries are recorded.
Outside the source country, the earliest documented arrival was at Honolulu, Oahu, Hi (United States) after 9:18 h.
The database records 1,362 deaths.
Houses destroyed: 11,661.
Damage is estimated at extreme (over US$ 25 million).
Map of observation sites
253Each dot is a documented observation site; colour and size show the observed water height. The triangle marks the source.
Tsunami arrival times
Documented arrival times from the NOAA/NCEI database, showing the earliest recorded location per country. Coverage is incomplete: a country without an entry was not necessarily spared.
- 0:00 hEarthquake (origin) · Dec 20, 1946, 7:19 PM UTC
- 9:18 hUnited States · Honolulu, Oahu, Hi · 0.10 m
- 21:12 hPeru · Talara · 0.05 m
4 places with a documented arrival time
Observations by country
| Country | Observation records | Maximum documented water height | Deaths | Earliest arrival |
|---|---|---|---|---|
| Japan | 246 | 6.50 m Shirahama | 288 | — |
 United States | 6 | 0.23 m Crescent City, Ca | — | 9:18 h |
 Peru | 1 | 0.05 m Talara | — | 21:12 h |
Highest documented water heights
15 / 253Individual documented observations for this event. Heights come from different measurement types and sources; not every location has a measured height.
| Location / station | Observed height | Distance from source | Country |
|---|---|---|---|
| Shirahama · Wakayama | 6.50 m | 81 km | Japan |
| Kamiko · Wakayama | 6.00 m | 82 km | Japan |
| Inamikawaseigan · Wakayama | 5.80 m | 100 km | Japan |
| Fukuroko · Wakayama | 5.50 m | 42 km | Japan |
| Gata · Kagoshima | 5.50 m | 570 km | Japan |
| Kata, Mie · Mie | 5.50 m | 98 km | Japan |
| Matsubara · Wakayama | 5.30 m | 110 km | Japan |
| None · Kochi | 5.00 m | 158 km | Japan |
| Sakihama · Kochi | 5.00 m | 160 km | Japan |
| Shinusa · Kochi | 5.00 m | 232 km | Japan |
| Tanabe · Wakayama | 5.00 m | 84 km | Japan |
| Tonda · Wakayama | 5.00 m | 74 km | Japan |
| Tosa Bay · Kochi | 5.00 m | 210 km | Japan |
| Hiro · Wakayama | 4.90 m | 120 km | Japan |
| Arita · Wakayama | 4.80 m | 43 km | Japan |
More tsunamis
Source: NOAA National Centers for Environmental Information (NCEI), Global Historical Tsunami Database. Confirmed events only. Deaths and damage are database estimates; older records are incomplete. Water heights come from different types of observation.