Magnitude7.3

Reviewed by USGSJapan91y ago

M7.3 earthquake 83 km E of Ishinomaki, Japan

Monday, November 2, 1936, 20:45:57 UTC · 38.279°N, 142.235°E

A magnitude 7.3 earthquake struck 83 km E of Ishinomaki, Japan on Monday, November 2, 1936, 20:45:57 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M7.3 on June 18, 1933.

Magnitude
7.3
Major · mw
Depth
35 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: 200 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

1.1 megatons of TNT

That is about 75 times the Hiroshima bomb. It released about 2,371 times the energy of a magnitude 5.0.

Tectonic setting

148 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 200 km

USGS lists 1 M2.5+ earthquake within 200 km in the following 30 days; the largest was M5.8 on November 21, 1936. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M6M71h6h1d3d7d14d30dMainshock M7.3
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 5.874 km SE of Ishinomaki, Japan91y ago · 44 km SW of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 166 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:

History · NOAA

Deadliest earthquakes in this area

NOAA’s significant-earthquake database lists 42 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 34,053 recorded deaths. The most severe:

  1. 1896M8.3

    Sanriku

    15 Jun 1896 · 204 km away

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

  2. 1933M8.4

    Sanriku

    2 Mar 1933 · 229 km away

    3,022 deathsExtreme damage ($25M+)tsunami

  3. 1828

    Sandyo In Etigo

    18 Dec 1828 · 255 km away

    1,443 deathsExtreme damage ($25M+)tsunami

  4. 1793M8.3

    Sanriku,Rikuzen,Rikuchu

    17 Feb 1793 · 156 km away

    745 deathsSevere damage ($5–24M)tsunami

  5. 1894M7.0

    Syonai

    22 Oct 1894 · 223 km away

    726 deathsSevere damage ($5–24M)tsunami

  6. 1804M7.3

    Kisakata

    10 Jul 1804 · 216 km away

    450 deathsExtreme damage ($25M+)tsunami

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

Nearby trackers

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