Reviewed by USGSJapan84y ago
M6.6 earthquake 163 km ENE of Hachinohe, Japan
Sunday, June 13, 1943, 17:39:18 UTC · 40.830°N, 143.389°E
A magnitude 6.6 earthquake struck 163 km ENE of Hachinohe, Japan on Sunday, June 13, 1943, 17:39:18 UTC, at a depth of 31.0 km (shallow). It is the strongest earthquake within 300 km since an M6.7 on June 13, 1943.
- Magnitude
- 6.6
- Strong · mw
- Depth
- 31 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: 100 km aftershock search area
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
89 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
31 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 lists 2 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M6.4 on June 15, 1943. 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 191 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.41933 Sanriku (Sanriku-oki) Earthquake, JapanMarch 2, 1933 · 207 km SE of this epicenter
- 7.978 km E of Hachinohe, JapanMarch 9, 1931 · 86 km W of this epicenter
- 7.7277 km SSE of Kushiro, JapanMay 3, 1919 · 189 km E of this epicenter
- 7.7217 km ESE of Kamaishi, JapanJuly 6, 1905 · 275 km S of this epicenter
- 7.6119 km SE of Kamaishi, JapanNovember 1, 1915 · 244 km S of this epicenter
- 7.5Near the east coast of Honshu, JapanAugust 9, 1901 · 95 km W of this epicenter
- 7.4off the east coast of Honshu, JapanOctober 10, 1939 · 259 km S of this epicenter
- 7.379 km ENE of Miyako, JapanMay 27, 1928 · 117 km SW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 36 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 32,897 recorded deaths. The most severe:
- 1896M8.3
Sanriku
15 Jun 1896 · 157 km away
27,122 deathsExtreme damage ($25M+)tsunami
- 1933M8.4
Sanriku
2 Mar 1933 · 207 km away
3,022 deathsExtreme damage ($25M+)tsunami
- 1766M6.9
Hirosaki
8 Mar 1766 · 226 km away
1,700 deathsSevere damage ($5–24M)tsunami
- 1793M8.3
Sanriku,Rikuzen,Rikuchu
17 Feb 1793 · 264 km away
745 deathsSevere damage ($5–24M)tsunami
- 1896
Senhoku, Ugo
31 Aug 1896 · 222 km away
206 deathsExtreme damage ($25M+)
- 1843M8.4
Hokkaido: Yezo, Kushiro, Nemuro
25 Apr 1843 · 254 km away
45 deathsModerate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.