July 25, 1970 Earthquake: Seikaido, Japan

Name: July 25, 1970 Earthquake: Seikaido, Japan
Start: 1970-07-25
Location: Seikaido, Japan

July 25, 1970 · M7

A magnitude 7 earthquake struck Seikaido, Japan on July 25, 1970 at 22:41:10 UTC, 34 km below the surface. It caused a tsunami.

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: July 25, 1970
Time: 22:41:10 UTC
Place: Seikaido, Japan
Magnitude: 7 (Ms)
Focal depth: 34 km (21 mi)
Tsunami: Yes: the tsunami it caused
Epicenter: 32.200° N, 131.700° E
Country: Japan
Region: East Asia
USGS record: The USGS’s page for this earthquake

The toll

Injuries: 13
Damage: Limited (under about $1 million)

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.

July 26. 1970. At approximately 07hr 41min [local time] an earthquake was felt throughout an extensive area of southern Japan. Railway transportation was temporarily disrupted because of damage to the track. There was no loss of human life, but thirteen people received serious injuries in the town of Miyazaki. The main shock was followed by aftershocks at a maximiun intensity of IV points (JMA). The frequency of the aftershocks soon decreased, and after 1700 hr of that same day, recognizable shocks from this earthquake were not recorded. After this earthquake, a weak tsunami was observed in the south of Japan. In dimensions and position, this source matches the source of the tsunami of November 2, 1931. (reference #417)

July 25, 1970, 22:41:10.7 UTC, 32.2 N, 131.7 E, depth 34 km, magnitude 7.0 MS. Slight damage at and near Miyazaki. Felt throughout Kyushu, on southern Shikoku, and in the northern Ryukyu Islands. A tsunami was generated. (reference #45)

Sources NCEI cites

The publications NCEI lists for this record. The numbers match the “reference #” notes in its account above.

#45 U.S. Department of the Interior, Geological Survey and U.S. Department of Commerce, National Oceanic and Atmospheric Administration (1928-1986). United States Earthquakes, Annual publication, published 1928-1986. vol.s for 1928-1965 issued by the U.S. Coast and Geodetic Survey; volumes for 1966-1969 issued by the National Earthquake Information Center; volume for 1970 issued by the National Geophysical Data Center; volumes for 1971-1972 issued by the National Geophysical And Solar-Terrestrial Data Center; volumes for 1973-1980 published jointly by the National Oceanic and Atmospheric Administration (NOAA) and the U.S. Geological Survey; volumes for 1981-1986 published by the U.S. Geological Survey. [on shelf]
#150 Iida, Kumizi (1984). Catalog of tsunamis in Japan and its neighboring countries. Aichi Institute of Technology, Yachigusa, Yakusa-cho, Toyota-shi, 470-03, Japan, 52 p.

Other significant earthquakes nearby

Within 200 km, the deadliest first.

Significant earthquakes of 1970 The 1900s Every quake the USGS located in 1970 Recent earthquakes near here This 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 2026-10-01. NCEI earthquake 6430. The written accounts and the magnitude estimates are from the USGS earthquake catalog, event iscgem794013, matched to this record by time, place and magnitude.