Reviewed by USGSJapan122y ago
M7.7 earthquake 217 km ESE of Kamaishi, Japan
Thursday, July 6, 1905, 16:20:46 UTC · 38.417°N, 144.119°E
A magnitude 7.7 earthquake struck 217 km ESE of Kamaishi, Japan on Thursday, July 6, 1905, 16:20:46 UTC, at a depth of 15.0 km (shallow). No earthquake of this size or larger appears within 300 km in the USGS catalog since 1900.
- Magnitude
- 7.7
- Major · mw
- Depth
- 15 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
4.8 megatons of TNT
That is about 320 times the Hiroshima bomb. It released about 10,116 times the energy of a magnitude 5.0.
Tectonic setting
11 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 has not published any M2.5+ earthquake within 200 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 5 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.5Near the east coast of Honshu, JapanAugust 9, 1901 · 289 km NW of this epicenter
- 7.2Near the east coast of Honshu, JapanAugust 9, 1901 · 270 km NW of this epicenter
- 7.0Northern Honshu, JapanMay 11, 1900 · 264 km W of this epicenter
- 7.0Near the east coast of Honshu, JapanJune 15, 1901 · 117 km NW of this epicenter
- 7.0Off the east coast of Honshu, JapanMay 2, 1902 · 66 km N of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 21 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 27,968 recorded deaths. The most severe:
- 1896M8.3
Sanriku
15 Jun 1896 · 121 km away
27,122 deathsExtreme damage ($25M+)tsunami
- 1793M8.3
Sanriku,Rikuzen,Rikuchu
17 Feb 1793 · 14 km away
745 deathsSevere damage ($5–24M)tsunami
- 1905M7.0
Off Fukushima
6 Jul 1905 · 175 km away
57 deathstsunami
- 1856M8.0
Oshima
23 Aug 1856 · 238 km away · intensity V
26 deathsModerate damage ($1–5M)tsunami
- 1901M8.2
Off Northeast Coast Honshu
9 Aug 1901 · 289 km away
18 deathsModerate damage ($1–5M)tsunami
- 1835M7.6
Sanriku
20 Jul 1835 · 202 km away
Severe damage ($5–24M)tsunami
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.