QuakeScout
Magnitude6.6

Reviewed by USGSJapan119y ago

M6.6 earthquake 227 km ESE of Ishinomaki, Japan

Monday, March 22, 1909, 20:03:42 UTC · 37.533°N, 143.638°E

A magnitude 6.6 earthquake struck 227 km ESE of Ishinomaki, Japan on Monday, March 22, 1909, 20:03:42 UTC, at a depth of 15.0 km (shallow). It is the strongest earthquake within 300 km since an M7.1 on March 13, 1909.

Magnitude
6.6
Strong · 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

116 kilotons of TNT

That is about 8 times the Hiroshima bomb. It released about 243 times the energy of a magnitude 5.0.

Tectonic setting

10 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 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 8 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

  1. 7.7217 km ESE of Kamaishi, JapanJuly 6, 1905 · 107 km NE of this epicenter
  2. 7.1150 km ESE of Hasaki, JapanMarch 13, 1909 · 276 km SW of this epicenter
  3. 7.082 km ENE of Hasaki, JapanMarch 12, 1909 · 250 km SW of this epicenter
  4. 7.0Northern Honshu, JapanMay 11, 1900 · 257 km NW of this epicenter
  5. 7.0Near the east coast of Honshu, JapanJune 15, 1901 · 172 km N of this epicenter
  6. 7.0Off the east coast of Honshu, JapanMay 2, 1902 · 166 km N of this epicenter
  7. 6.870 km E of Namie, JapanJanuary 15, 1908 · 164 km W of this epicenter
  8. 6.6132 km ESE of Iwaki, JapanApril 8, 1906 · 148 km SW of this epicenter

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 17 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 27,924 recorded deaths. The most severe:

  1. 1896M8.3

    Sanriku

    15 Jun 1896 · 221 km away

    27,122 deathsExtreme damage ($25M+)tsunami

  2. 1793M8.3

    Sanriku,Rikuzen,Rikuchu

    17 Feb 1793 · 112 km away

    745 deathsSevere damage ($5–24M)tsunami

  3. 1905M7.0

    Off Fukushima

    6 Jul 1905 · 93 km away

    57 deathstsunami

  4. 1835M7.6

    Sanriku

    20 Jul 1835 · 158 km away

    Severe damage ($5–24M)tsunami

  5. 1898M7.2

    Sanriku

    22 Apr 1898 · 186 km away

    Severe damage ($5–24M)tsunami

  6. 1717M7.6

    Hanamaki

    13 May 1717 · 183 km away

    Moderate damage ($1–5M)

NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.

Nearby trackers

Closest city pages