Magnitude7.0

Reviewed by USGSJapan104y ago

M7.0 earthquake 93 km NNE of Naze, Japan

Saturday, November 3, 1923, 16:19:24 UTC · 29.102°N, 129.950°E

A magnitude 7.0 earthquake struck 93 km NNE of Naze, Japan on Saturday, November 3, 1923, 16:19:24 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
7.0
Strong · mw
Depth
35 km
Shallow
Felt reports
0
Did You Feel It?
Est. shaking
V
Moderate (ShakeMap)
PAGER alert
None
Not issued
Tsunami
No flag
USGS feed

Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

430 kilotons of TNT

That is about 29 times the Hiroshima bomb. It released about 902 times the energy of a magnitude 5.0.

Tectonic setting

91 km

from the nearest mapped plate boundary, between the Yangtze 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 lists 1 M2.5+ earthquake within 100 km in the following 30 days; the largest was M7.2 on November 5, 1923. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M6M71h6h1d3d7d14d30dMainshock M7.0
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 7.2101 km NE of Naze, Japan104y ago · 40 km SE of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 17 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 5 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 75 recorded deaths. The most severe:

  1. 1914M7.1

    Sakurijima

    12 Jan 1914 · 284 km away

    63 deaths$19 million damagetsunami

  2. 1911M8.0

    Ryukyu Islands

    15 Jun 1911 · 123 km away

    12 deathsSevere damage ($5–24M)tsunami

  3. 1901M7.9

    Ryukyu Islands

    24 Jun 1901 · 234 km away

    Limited damage (under $1M)tsunami

  4. 1916M8.0

    Duda

    1 Feb 1916 · 157 km away

  5. 1904M7.9

    Kyushu

    24 Aug 1904 · 100 km away

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

Nearby trackers

Closest city pages