QuakeScout
Magnitude7.5

Reviewed by USGSJapan66y ago

M7.5 earthquake 18 km NNE of Nichinan, Japan

Sunday, February 26, 1961, 18:10:52 UTC · 31.739°N, 131.475°E

A magnitude 7.5 earthquake struck 18 km NNE of Nichinan, Japan on Sunday, February 26, 1961, 18:10:52 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M8.0 on November 18, 1941.

Magnitude
7.5
Major · mw
Depth
35 km
Shallow
Felt reports
0
Did You Feel It?
Est. shaking
VII
Very strong (ShakeMap)
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

3.1 megatons of TNT

That is about 204 times the Hiroshima bomb. It released about 6,457 times the energy of a magnitude 5.0.

Tectonic setting

9 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

35 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 has not published any M2.5+ earthquake within 200 km in the 30 days after this event.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 74 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 8.01941 Hyuganada EarthquakeNovember 18, 1941 · 62 km NE of this epicenter
  2. 7.958 km ESE of Takanabe, JapanNovember 2, 1931 · 56 km E of this epicenter
  3. 7.518 km SE of Honmachi, JapanNovember 10, 1909 · 100 km NW of this epicenter
  4. 7.4152 km ESE of Koshima, JapanFebruary 1, 1916 · 251 km S of this epicenter
  5. 7.422 km N of Nishinoomote, JapanJuly 13, 1923 · 99 km SW of this epicenter
  6. 7.229 km ESE of Takanabe, JapanApril 13, 1913 · 45 km NE of this epicenter
  7. 7.161 km ESE of Nishinoomote, JapanAugust 24, 1904 · 142 km S of this epicenter
  8. 7.0122 km SSE of Koshima, JapanMarch 21, 1942 · 293 km S of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 21 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 15,157 recorded deaths. The most severe:

  1. 1792M6.4

    Kyusyu Island

    21 May 1792 · 162 km away

    15,030 deathsExtreme damage ($25M+)tsunami

  2. 1914M7.1

    Sakurijima

    12 Jan 1914 · 78 km away

    63 deaths$19 million damagetsunami

  3. 1922

    Kyushu

    7 Dec 1922 · 154 km away

    27 deathsLimited damage (under $1M)

  4. 1889M6.3

    Kumamoto

    28 Jul 1889 · 139 km away

    20 deathsLimited damage (under $1M)

  5. 1905M7.8

    Aki

    2 Jun 1905 · 256 km away

    11 deathsLimited damage (under $1M)

  6. 1961M7.3

    Miyazaki

    26 Feb 1961 · 34 km away

    2 deathsModerate damage ($1–5M)tsunami

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers

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