Reviewed by USGSJapan75y ago
M6.9 earthquake 110 km ESE of Shizunai-furukawachō, Japan
Sunday, March 9, 1952, 17:03:51 UTC · 41.831°N, 143.525°E
A magnitude 6.9 earthquake struck 110 km ESE of Shizunai-furukawachō, Japan on Sunday, March 9, 1952, 17:03:51 UTC, at a depth of 49.5 km (shallow). It is the strongest earthquake within 300 km since an M8.1 on March 4, 1952.
- Magnitude
- 6.9
- Strong · mw
- Depth
- 50 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- VI
- Strong (ShakeMap)
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 100 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
338 kilotons of TNT
That is about 22 times the Hiroshima bomb. It released about 708 times the energy of a magnitude 5.0.
Tectonic setting
131 km
from the nearest mapped plate boundary, between the Okhotsk and Pacific plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
50 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 M6.0 on March 11, 1952. 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 184 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11952 Tokachi-Oki EarthquakeMarch 4, 1952 · 42 km NE of this epicenter
- 7.978 km E of Hachinohe, JapanMarch 9, 1931 · 166 km SW of this epicenter
- 7.7277 km SSE of Kushiro, JapanMay 3, 1919 · 219 km SE of this epicenter
- 7.5Near the east coast of Honshu, JapanAugust 9, 1901 · 171 km SW of this epicenter
- 7.379 km ENE of Miyako, JapanMay 27, 1928 · 225 km S of this epicenter
- 7.3169 km ENE of Hachinohe, JapanJune 13, 1943 · 93 km S of this epicenter
- 7.2Near the east coast of Honshu, JapanAugust 9, 1901 · 171 km SW of this epicenter
- 7.2192 km ENE of Miyako, JapanOctober 18, 1935 · 183 km S of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 34 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 29,152 recorded deaths. The most severe:
- 1896M8.3
Sanriku
15 Jun 1896 · 262 km away
27,122 deathsExtreme damage ($25M+)tsunami
- 1766M6.9
Hirosaki
8 Mar 1766 · 257 km away
1,700 deathsSevere damage ($5–24M)tsunami
- 1896
Senhoku, Ugo
31 Aug 1896 · 294 km away
206 deathsExtreme damage ($25M+)
- 1843M8.4
Hokkaido: Yezo, Kushiro, Nemuro
25 Apr 1843 · 206 km away
45 deathsModerate damage ($1–5M)tsunami
- 1952M8.1
Hokkaido
4 Mar 1952 · 44 km away · intensity IX
33 deathsSevere damage ($5–24M)tsunami
- 1856M8.0
Oshima
23 Aug 1856 · 148 km away · intensity V
26 deathsModerate damage ($1–5M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.