Reviewed by USGSJapan113y ago
M6.6 earthquake 30 km E of Ishinomaki, Japan
Monday, March 8, 1915, 15:29:54 UTC · 38.408°N, 141.650°E
A magnitude 6.6 earthquake struck 30 km E of Ishinomaki, Japan on Monday, March 8, 1915, 15:29:54 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.0 on March 14, 1914.
- Magnitude
- 6.6
- Strong · 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
133 kilotons of TNT
That is about 9 times the Hiroshima bomb. It released about 279 times the energy of a magnitude 5.0.
Tectonic setting
201 km
from the nearest mapped plate boundary, between the Pacific and Okhotsk plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
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 100 km
USGS has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 15 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.7217 km ESE of Kamaishi, JapanJuly 6, 1905 · 215 km E of this epicenter
- 7.5Near the east coast of Honshu, JapanAugust 9, 1901 · 250 km N of this epicenter
- 7.2Near the east coast of Honshu, JapanAugust 9, 1901 · 244 km N of this epicenter
- 7.013 km ESE of Yokote, JapanMarch 14, 1914 · 128 km NW of this epicenter
- 7.082 km ENE of Hasaki, JapanMarch 12, 1909 · 279 km S of this epicenter
- 7.0Northern Honshu, JapanMay 11, 1900 · 58 km NW of this epicenter
- 7.0Near the east coast of Honshu, JapanJune 15, 1901 · 134 km NE of this epicenter
- 7.0Off the east coast of Honshu, JapanMay 2, 1902 · 214 km E of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 37 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 32,731 recorded deaths. The most severe:
- 1896M8.3
Sanriku
15 Jun 1896 · 237 km away
27,122 deathsExtreme damage ($25M+)tsunami
- 1766M6.9
Hirosaki
8 Mar 1766 · 289 km away
1,700 deathsSevere damage ($5–24M)tsunami
- 1828
Sandyo In Etigo
18 Dec 1828 · 214 km away
1,443 deathsExtreme damage ($25M+)tsunami
- 1793M8.3
Sanriku,Rikuzen,Rikuchu
17 Feb 1793 · 205 km away
745 deathsSevere damage ($5–24M)tsunami
- 1894M7.0
Syonai
22 Oct 1894 · 170 km away
726 deathsSevere damage ($5–24M)tsunami
- 1804M7.3
Kisakata
10 Jul 1804 · 164 km away
450 deathsExtreme damage ($25M+)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.