Reviewed by USGSJapan104y ago
M7.4 earthquake 22 km N of Nishinoomote, Japan
Friday, July 13, 1923, 11:13:41 UTC · 30.930°N, 131.032°E
A magnitude 7.4 earthquake struck 22 km N of Nishinoomote, Japan on Friday, July 13, 1923, 11:13:41 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.4 on February 1, 1916.
- Magnitude
- 7.4
- Major · 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 earthquakeDashed circle: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
1.7 megatons of TNT
That is about 114 times the Hiroshima bomb. It released about 3,589 times the energy of a magnitude 5.0.
Tectonic setting
107 km
from the nearest mapped plate boundary, between the Amur and Okinawa plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
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 lists 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M6.6 on July 13, 1923. 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 17 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.9108 km NW of Naze, JapanJune 15, 1911 · 293 km SW of this epicenter
- 7.518 km SE of Honmachi, JapanNovember 10, 1909 · 166 km N of this epicenter
- 7.4152 km ESE of Koshima, JapanFebruary 1, 1916 · 177 km SE of this epicenter
- 7.229 km ESE of Takanabe, JapanApril 13, 1913 · 142 km NE of this epicenter
- 7.161 km ESE of Nishinoomote, JapanAugust 24, 1904 · 72 km SE of this epicenter
- 6.88 km NNE of Kajiki, JapanJanuary 12, 1914 · 103 km N of this epicenter
- 6.786 km SE of Koshima, JapanNovember 28, 1914 · 149 km S of this epicenter
- 6.7120 km E of Nishinoomote, JapanJanuary 5, 1913 · 119 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 13 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 15,140 recorded deaths. The most severe:
- 1792M6.4
Kyusyu Island
21 May 1792 · 219 km away
15,030 deathsExtreme damage ($25M+)tsunami
- 1914M7.1
Sakurijima
12 Jan 1914 · 80 km away
63 deaths$19 million damagetsunami
- 1922
Kyushu
7 Dec 1922 · 209 km away
27 deathsLimited damage (under $1M)
- 1889M6.3
Kumamoto
28 Jul 1889 · 210 km away
20 deathsLimited damage (under $1M)
- 1769M7.4
Sw. Kyushu Island, Japan
29 Aug 1769 · 178 km away
Moderate damage ($1–5M)tsunami
- 1899M7.1
Seikaido
24 Nov 1899 · 142 km away
Limited damage (under $1M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.