Reviewed by USGSJapan100y ago
M5.6 earthquake 157 km SE of Katsuura, Japan
Wednesday, August 24, 1927, 23:55:29 UTC · 34.034°N, 141.375°E
A magnitude 5.6 earthquake struck 157 km SE of Katsuura, Japan on Wednesday, August 24, 1927, 23:55:29 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M5.7 on August 24, 1927.
- Magnitude
- 5.6
- Moderate · mw
- Depth
- 35 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
4 kilotons of TNT
That is about 1/4 of the Hiroshima bomb. It released about 8 times the energy of a magnitude 5.0.
Tectonic setting
36 km
from the nearest mapped plate boundary, between the Okhotsk and Philippine Sea 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 75 km
USGS has not published any M2.5+ earthquake within 75 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 60 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 · 231 km NW of this epicenter
- 7.85 km E of Tateyama, JapanSeptember 2, 1923 · 170 km NW of this epicenter
- 7.3190 km SE of Hasaki, JapanSeptember 7, 1906 · 133 km NE of this epicenter
- 7.264 km ENE of Hasaki, JapanJune 1, 1923 · 212 km N of this epicenter
- 7.238 km SSW of Shimoda, JapanOctober 24, 1905 · 235 km W of this epicenter
- 7.167 km ENE of Kashima-shi, JapanAugust 14, 1924 · 241 km N of this epicenter
- 7.1150 km ESE of Hasaki, JapanMarch 13, 1909 · 165 km NE of this epicenter
- 7.082 km ENE of Hasaki, JapanMarch 12, 1909 · 210 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 19 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 117,492 recorded deaths. The most severe:
- 1923M7.9
Tokyo, Yokohama
1 Sep 1923 · 209 km away
105,385 deaths$600 million damagetsunami
- 1855M7.0
Tokyo
11 Nov 1855 · 230 km away
6,757 deathsExtreme damage ($25M+)tsunami
- 1703M8.2
Off Sw Boso Peninsula
30 Dec 1703 · 166 km away
5,233 deathsExtreme damage ($25M+)tsunami
- 1853
Odawara
11 Mar 1853 · 236 km away
79 deathsSevere damage ($5–24M)
- 1894M7.5
Tokyo
20 Jun 1894 · 229 km away
24 deathsLimited damage (under $1M)
- 1924
Sagami
15 Jan 1924 · 236 km away
14 deathsSevere damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.