Reviewed by USGSJapan59y ago
M7.5 earthquake 60 km ESE of Nobeoka, Japan
Monday, April 1, 1968, 00:42:05 UTC · 32.479°N, 132.294°E
A magnitude 7.5 earthquake struck 60 km ESE of Nobeoka, Japan on Monday, April 1, 1968, 00:42:05 UTC, at a depth of 31.2 km (shallow). It is the strongest earthquake within 300 km since an M7.5 on February 26, 1961.
- Magnitude
- 7.5
- Major · mw
- Depth
- 31 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VI
- Strong (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
2.7 megatons of TNT
That is about 178 times the Hiroshima bomb. It released about 5,623 times the energy of a magnitude 5.0.
Tectonic setting
96 km
from the nearest mapped plate boundary, between the Amur and Okinawa plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
31 km
Shallow earthquakes (under 70 km) produce the strongest surface shaking for their size, so they are the ones most likely to cause damage near the epicenter.
Did You Feel It?
Where it was felt
No “Did You Feel It?” reports have been published for this event yet. If you felt it, you can add your report on the USGS website.
I felt it — report to USGS ↗USGS PAGER estimate
Who was exposed to shaking
USGS publishes PAGER impact estimates for significant earthquakes, usually within an hour. No PAGER estimate is available for this event.
After the main event
Aftershocks within 200 km
USGS lists 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M6.8 on April 1, 1968. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 81 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.01941 Hyuganada EarthquakeNovember 18, 1941 · 51 km SW of this epicenter
- 7.958 km ESE of Takanabe, JapanNovember 2, 1931 · 70 km S of this epicenter
- 7.518 km NNE of Nichinan, JapanFebruary 26, 1961 · 113 km SW of this epicenter
- 7.518 km SE of Honmachi, JapanNovember 10, 1909 · 145 km W of this epicenter
- 7.422 km N of Nishinoomote, JapanJuly 13, 1923 · 210 km SW of this epicenter
- 7.229 km ESE of Takanabe, JapanApril 13, 1913 · 68 km SW of this epicenter
- 7.161 km ESE of Nishinoomote, JapanAugust 24, 1904 · 234 km S of this epicenter
- 6.928 km ENE of Nichinan, JapanMay 9, 1948 · 109 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 26 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 24,965 recorded deaths. The most severe:
- 1792M6.4
Kyusyu Island
21 May 1792 · 190 km away
15,030 deathsExtreme damage ($25M+)tsunami
- 1707M8.4
Nankaido
28 Oct 1707 · 247 km away
5,000 deathsExtreme damage ($25M+)tsunami
- 1854M8.4
Nankaido
24 Dec 1854 · 262 km away
3,000 deathsExtreme damage ($25M+)tsunami
- 1711M6.7
Seionaikai, Japan
20 Dec 1711 · 257 km away
1,000 deathsSevere damage ($5–24M)tsunami
- 1872M7.4
Honshu: Sw
14 Mar 1872 · 271 km away
804 deathsExtreme damage ($25M+)tsunami
- 1914M7.1
Sakurijima
12 Jan 1914 · 183 km away
63 deaths$19 million damagetsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.