April 20, 1975 Earthquake: Oita, Arosan, Japan

Date

April 20, 1975

Time

17:35:50 UTC

Place

Oita, Arosan, Japan

Magnitude

6.1 (Ms)

Magnitude scales

Ms 6.1 · mb 5.7 · Unspecified 6.4

Focal depth

7 km (4 mi)

Intensity

VI, strong shaking, on the Modified Mercalli scale

Tsunami

None recorded

Epicenter

33.190° N, 131.300° E

Country

Japan

Region

East Asia

USGS record

The USGS’s page for this earthquake

Ms: surface-wave magnitude. mb: body-wave (P-wave) magnitude. Unspecified: the method was not stated in the published sources. NCEI’s headline magnitude is the best of these for the earthquake.

Injuries

8

Damage

Severe (about $5 to $25 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.

1. #1053 National Earthquake Information Center (NEIC) (1971 to 2013). Preliminary Determination of Epicenters (PDE), a weekly and monthly publication, National Earthquake Information Center, U.S. Geological Survey, Golden, Colorado, 1971 to 2013.
2. #1167 Rothe, J.P. (1974-1975). Annual Summary of Information on Natural Disasters, UNESCO, Paris, France, no. 9 (1974, missing from archives) and no. 10 (1975), 107 p.

• May 21, 1792, Kyusyu Island, JapanM6.4 · 15,030 deaths · 6,200 houses destroyed · 103 km
• June 30, 744, Shimabara, Yatsushiro, Higo, JapanM6.4 · 1,520 deaths · 470 houses destroyed · 115 km
• June 16, 1026, Off Masuda, Shimane Prefecture, JapanM7.5 · 1,001 deaths · 3,000 houses destroyed · 185 km
• September 4, 1596, Beppu Bay, JapanM6.9 · 708 deaths · 80 houses destroyed · 39 km
• April 15, 2016, Kumamoto, Oita, JapanM7 · 273 deaths · $20 billion · 43,386 houses destroyed · 68 km
• October 30, 1662, Hiuganada, JapanM7.9 · 200 deaths · 2,500 houses destroyed · 178 km
• January 12, 1914, Sakurijima, JapanM7.1 · 63 deaths · $19 million · 2,268 houses destroyed · 189 km
• September 10, 1597, Beppu Bay, JapanM6.4 · 40 deaths · 30 km
• July 28, 2026, Kumamoto, JapanM6.8 · 38 deaths · 3,539 houses destroyed · 78 km
• December 7, 1922, Kyushu, Japan27 deaths · 108 km
• July 28, 1889, Kumamoto, JapanM6.3 · 20 deaths · 239 houses destroyed · 71 km
• August 6, 1984, Nobeoka, Kyushu, JapanM6.7 · 20 deaths · 108 km
• June 2, 1905, Aki, JapanM7.8 · 11 deaths · 59 houses destroyed · 111 km
• July 12, 1676, Tuwano, Japan7 deaths · 159 km
• February 21, 1968, Kyushu, JapanM6.3 · 3 deaths · 148 km

Significant earthquakes of 1975The 1900sEvery quake the USGS located in 1975Recent earthquakes near hereThis day in weather history

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 4689. The written accounts and the magnitude estimates are from the USGS earthquake catalog, event usp0000aq9, matched to this record by time, place and magnitude.