Magnitude6.9

Reviewed by USGSJapan98y ago

M6.9 earthquake 31 km ESE of Miyazaki, Japan

Tuesday, May 21, 1929, 16:35:34 UTC · 31.855°N, 131.743°E

A magnitude 6.9 earthquake struck 31 km ESE of Miyazaki, Japan on Tuesday, May 21, 1929, 16:35:34 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.4 on July 13, 1923.

Magnitude
6.9
Strong · mw
Depth
35 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 earthquakeColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

304 kilotons of TNT

That is about 20 times the Hiroshima bomb. It released about 638 times the energy of a magnitude 5.0.

Tectonic setting

11 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 100 km

USGS has not published any M2.5+ earthquake within 100 km in the 30 days after this event.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 24 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 16 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 15,151 recorded deaths. The most severe:

  1. 1792M6.4

    Kyusyu Island

    21 May 1792 · 172 km away

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

  2. 1914M7.1

    Sakurijima

    12 Jan 1914 · 106 km away

    63 deaths$19 million damagetsunami

  3. 1922

    Kyushu

    7 Dec 1922 · 165 km away

    27 deathsLimited damage (under $1M)

  4. 1889M6.3

    Kumamoto

    28 Jul 1889 · 144 km away

    20 deathsLimited damage (under $1M)

  5. 1905M7.8

    Aki

    2 Jun 1905 · 240 km away

    11 deathsLimited damage (under $1M)

  6. 1769M7.4

    Sw. Kyushu Island, Japan

    29 Aug 1769 · 55 km away

    Moderate damage ($1–5M)tsunami

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

Nearby trackers

Closest city pages