Reviewed by USGSJapan103y ago
M6.6 earthquake 98 km ESE of Kitaibaraki, Japan
Monday, August 25, 1924, 14:31:01 UTC · 36.486°N, 141.788°E
A magnitude 6.6 earthquake struck 98 km ESE of Kitaibaraki, Japan on Monday, August 25, 1924, 14:31:01 UTC, at a depth of 25.0 km (shallow). It is the strongest earthquake within 300 km since an M7.1 on August 14, 1924.
- Magnitude
- 6.6
- Strong · mw
- Depth
- 25 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquake
In context
How big was it, and why here?
Energy released
104 kilotons of TNT
That is about 7 times the Hiroshima bomb. It released about 219 times the energy of a magnitude 5.0.
Tectonic setting
91 km
from the nearest mapped plate boundary, between the Pacific and Okhotsk plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
Depth: shallow
25 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 48 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 · 258 km SW of this epicenter
- 7.85 km E of Tateyama, JapanSeptember 2, 1923 · 237 km SW of this epicenter
- 7.7217 km ESE of Kamaishi, JapanJuly 6, 1905 · 297 km NE of this epicenter
- 7.6119 km SE of Kamaishi, JapanNovember 1, 1915 · 264 km NE of this epicenter
- 7.3190 km SE of Hasaki, JapanSeptember 7, 1906 · 205 km S of this epicenter
- 7.264 km ENE of Hasaki, JapanJune 1, 1923 · 66 km SW of this epicenter
- 7.167 km ENE of Kashima-shi, JapanAugust 14, 1924 · 51 km SW of this epicenter
- 7.1150 km ESE of Hasaki, JapanMarch 13, 1909 · 146 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 29 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 119,737 recorded deaths. The most severe:
- 1923M7.9
Tokyo, Yokohama
1 Sep 1923 · 258 km away
105,385 deaths$600 million damagetsunami
- 1855M7.0
Tokyo
11 Nov 1855 · 201 km away
6,757 deathsExtreme damage ($25M+)tsunami
- 1703M8.2
Off Sw Boso Peninsula
30 Dec 1703 · 231 km away
5,233 deathsExtreme damage ($25M+)tsunami
- 1828
Sandyo In Etigo
18 Dec 1828 · 232 km away
1,443 deathsExtreme damage ($25M+)tsunami
- 1793M8.3
Sanriku,Rikuzen,Rikuchu
17 Feb 1793 · 297 km away
745 deathsSevere damage ($5–24M)tsunami
- 1853
Odawara
11 Mar 1853 · 233 km away
79 deathsSevere damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.