Reviewed by USGSJapan103y ago
M7.1 earthquake 67 km ENE of Kashima-shi, Japan
Thursday, August 14, 1924, 18:02:40 UTC · 36.199°N, 141.340°E
A magnitude 7.1 earthquake struck 67 km ENE of Kashima-shi, Japan on Thursday, August 14, 1924, 18:02:40 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.8 on September 2, 1923.
- Magnitude
- 7.1
- Major · mw
- Depth
- 15 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
747 kilotons of TNT
That is about 50 times the Hiroshima bomb. It released about 1,567 times the energy of a magnitude 5.0.
Tectonic setting
113 km
from the nearest mapped plate boundary, between the Pacific and Okhotsk plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
15 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 4 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.6 on August 25, 1924. 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 42 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.05 km SSE of Ōiso, JapanSeptember 1, 1923 · 207 km SW of this epicenter
- 7.85 km E of Tateyama, JapanSeptember 2, 1923 · 186 km SW of this epicenter
- 7.3190 km SE of Hasaki, JapanSeptember 7, 1906 · 195 km SE of this epicenter
- 7.264 km ENE of Hasaki, JapanJune 1, 1923 · 33 km SE of this epicenter
- 7.1150 km ESE of Hasaki, JapanMarch 13, 1909 · 140 km SE of this epicenter
- 7.082 km ENE of Hasaki, JapanMarch 12, 1909 · 48 km SE of this epicenter
- 7.0208 km SE of Katsuura, JapanApril 21, 1916 · 280 km S of this epicenter
- 7.0Northern Honshu, JapanMay 11, 1900 · 279 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 25 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 118,992 recorded deaths. The most severe:
- 1923M7.9
Tokyo, Yokohama
1 Sep 1923 · 206 km away
105,385 deaths$600 million damagetsunami
- 1855M7.0
Tokyo
11 Nov 1855 · 152 km away
6,757 deathsExtreme damage ($25M+)tsunami
- 1703M8.2
Off Sw Boso Peninsula
30 Dec 1703 · 180 km away
5,233 deathsExtreme damage ($25M+)tsunami
- 1828
Sandyo In Etigo
18 Dec 1828 · 218 km away
1,443 deathsExtreme damage ($25M+)tsunami
- 1853
Odawara
11 Mar 1853 · 183 km away
79 deathsSevere damage ($5–24M)
- 1905M7.0
Off Fukushima
6 Jul 1905 · 174 km away
57 deathstsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.