March 20, 1939 Earthquake: Seikaido, Japan
A magnitude 6.6 earthquake struck Seikaido, Japan on March 20, 1939 at 03:22 UTC, 20 km below the surface. It killed 1 person, counting the tsunami it caused.
Map
Where it struck, with the other significant earthquakes within 200 km. Circles are sized and colored by magnitude; select one for its page.
The earthquake
- Date
- March 20, 1939
- Time
- 03:22 UTC
- Place
- Seikaido, Japan
- Magnitude
- 6.6 (Ms)
- Focal depth
- 20 km (12 mi)
- Tsunami
- Yes: the tsunami it caused
- Epicenter
- 32.300° N, 132.000° E
- Country
- Japan
The toll
- Deaths
- 1 with its tsunami and other effects
- Damage
- Limited (under about $1 million) with its tsunami and other effects
- Houses destroyed
- 1 with its tsunami and other effects
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.
Reference #150:
1939, March 20 32.3 132 E, magnitude 6.6. Hosojima 7cm, Aburatsu 16cm, Muroto 8Ocm, Tosa-Shimizu 12cm (peak-to-trough). 1 death, 1 house destroyed.
Reference #414:
1939, March 20, 1939, at 12:22 [local time] there was an earthquake with source off the coast of Miyazaki Prefecture. It was felt with a force of 6 degrees (IV JMA) in the prefectures of Miyazaki, Kumamoto, and Oita. It caused a weak tsunami.
Iida et al. (1967): 20.III; 3h22m; 32.3 N., 131.7 E.; 10 km; M=6.6, m=-0.3.
Other significant earthquakes nearby
Within 200 km, the deadliest first.
- May 21, 1792, Kyusyu Island, Japan
- June 30, 744, Shimabara, Yatsushiro, Higo, Japan
- September 4, 1596, Beppu Bay, Japan
- April 15, 2016, Kumamoto, Oita, Japan
- October 30, 1662, Hiuganada, Japan
- January 12, 1914, Sakurijima, Japan
- September 10, 1597, Beppu Bay, Japan
- July 28, 2026, Kumamoto, Japan
- December 7, 1922, Kyushu, Japan
- August 6, 1984, Nobeoka, Kyushu, Japan
- July 28, 1889, Kumamoto, Japan
- June 2, 1905, Aki, Japan
- February 21, 1968, Kyushu, Japan
- March 18, 1987, Miyazaki, Naze, Kyushu, Japan
- November 18, 1941, Shikoku, Japan
More
Significant earthquakes of 1939The 1900sEvery quake the USGS located in 1939Recent earthquakes near hereThis day in weather history
Sources
Significant earthquakes 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 earthquake 6339.