Reviewed by USGSJapan96y ago
M5.7 earthquake 159 km ENE of Miyako, Japan
Monday, March 9, 1931, 17:56:02 UTC · 40.385°N, 143.544°E
A magnitude 5.7 earthquake struck 159 km ENE of Miyako, Japan on Monday, March 9, 1931, 17:56:02 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.9 on March 9, 1931.
- Magnitude
- 5.7
- 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 earthquakeDashed circle: 75 km aftershock search area
In context
How big was it, and why here?
Energy released
5 kilotons of TNT
That is about 1/3 of the Hiroshima bomb. It released about 10 times the energy of a magnitude 5.0.
Tectonic setting
70 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
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 lists 2 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.9 on March 15, 1931. 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 92 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.978 km E of Hachinohe, JapanMarch 9, 1931 · 98 km W of this epicenter
- 7.7277 km SSE of Kushiro, JapanMay 3, 1919 · 179 km E of this epicenter
- 7.7217 km ESE of Kamaishi, JapanJuly 6, 1905 · 224 km S of this epicenter
- 7.6119 km SE of Kamaishi, JapanNovember 1, 1915 · 197 km S of this epicenter
- 7.5Near the east coast of Honshu, JapanAugust 9, 1901 · 108 km W of this epicenter
- 7.379 km ENE of Miyako, JapanMay 27, 1928 · 84 km SW of this epicenter
- 7.2Near the east coast of Honshu, JapanAugust 9, 1901 · 89 km W of this epicenter
- 7.1123 km SE of Honchō, JapanJuly 29, 1917 · 93 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 31 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 29,862 recorded deaths. The most severe:
- 1896M8.3
Sanriku
15 Jun 1896 · 106 km away
27,122 deathsExtreme damage ($25M+)tsunami
- 1766M6.9
Hirosaki
8 Mar 1766 · 247 km away
1,700 deathsSevere damage ($5–24M)tsunami
- 1793M8.3
Sanriku,Rikuzen,Rikuchu
17 Feb 1793 · 213 km away
745 deathsSevere damage ($5–24M)tsunami
- 1896
Senhoku, Ugo
31 Aug 1896 · 220 km away
206 deathsExtreme damage ($25M+)
- 1843M8.4
Hokkaido: Yezo, Kushiro, Nemuro
25 Apr 1843 · 273 km away
45 deathsModerate damage ($1–5M)tsunami
- 1856M8.0
Oshima
23 Aug 1856 · 13 km away · intensity V
26 deathsModerate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.