Reviewed by USGSJapan84y ago
M7.1 earthquake 96 km ESE of Takahagi, Japan
Sunday, April 11, 1943, 14:46:00 UTC · 36.301°N, 141.662°E
A magnitude 7.1 earthquake struck 96 km ESE of Takahagi, Japan on Sunday, April 11, 1943, 14:46:00 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.4 on October 10, 1939.
- Magnitude
- 7.1
- Major · mw
- Depth
- 15 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- IV
- Light (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
90 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
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 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M6.4 on April 12, 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 212 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 · 238 km SW of this epicenter
- 7.85 km E of Tateyama, JapanSeptember 2, 1923 · 214 km SW of this epicenter
- 7.8105 km E of Iwaki, JapanNovember 5, 1938 · 83 km NE of this epicenter
- 7.7116 km E of Namie, JapanNovember 6, 1938 · 133 km NE of this epicenter
- 7.769 km ESE of Kitaibaraki, JapanMay 23, 1938 · 32 km NW of this epicenter
- 7.7116 km ESE of Namie, JapanNovember 5, 1938 · 107 km NE of this epicenter
- 7.6119 km SE of Kamaishi, JapanNovember 1, 1915 · 288 km NE of this epicenter
- 7.6141 km ESE of Namie, JapanNovember 6, 1938 · 108 km NE of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 41 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 119,268 recorded deaths. The most severe:
- 1923M7.9
Tokyo, Yokohama
1 Sep 1923 · 237 km away
105,385 deaths$600 million damagetsunami
- 1855M7.0
Tokyo
11 Nov 1855 · 183 km away
6,757 deathsExtreme damage ($25M+)tsunami
- 1703M8.2
Off Sw Boso Peninsula
30 Dec 1703 · 209 km away
5,233 deathsExtreme damage ($25M+)tsunami
- 1828
Sandyo In Etigo
18 Dec 1828 · 234 km away
1,443 deathsExtreme damage ($25M+)tsunami
- 1930M7.1
Honshu: Idu
25 Nov 1930 · 281 km away
259 deathsExtreme damage ($25M+)
- 1853
Odawara
11 Mar 1853 · 214 km away
79 deathsSevere damage ($5–24M)
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.