Magnitude8.1

Reviewed by USGS109y ago

M8.1 earthquake 1918 Kuril Islands Earthquake

Saturday, September 7, 1918, 17:16:27 UTC · 44.998°N, 152.320°E

A magnitude 8.1 earthquake struck 1918 Kuril Islands Earthquake on Saturday, September 7, 1918, 17:16:27 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
8.1
Great · mw
Depth
15 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: 400 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)

In context

How big was it, and why here?

Energy released

21 megatons of TNT

That is about 1,415 times the Hiroshima bomb. It released about 44,668 times the energy of a magnitude 5.0.

Tectonic setting

18 km

from the nearest mapped plate boundary, between the Okhotsk and Pacific 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 400 km

USGS lists 3 M2.5+ earthquakes within 400 km in the following 30 days; the largest was M6.5 on September 14, 1918. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

M3M4M5M6M7M81h6h1d3d7d14d30dMainshock M8.1
Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.
  1. 6.5254 km E of Kuril’sk, Russia109y ago · 97 km W of this epicenter
  2. 5.9280 km ENE of Kuril’sk, Russia109y ago · 137 km NW of this epicenter
  3. 6.2east of the Kuril Islands109y ago · 102 km SE of this epicenter

Regional history

Past M5+ earthquakes within 300 km

USGS lists 10 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 7 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 35 recorded deaths. The most severe:

  1. 1918M8.3

    Kuril Islands

    7 Sep 1918 · 85 km away

    23 deathsModerate damage ($1–5M)tsunami

  2. 1780M7.5

    Kuril Islands

    29 Jun 1780 · 94 km away

    12 deathsLimited damage (under $1M)tsunami

  3. 1913M7.5

    Kuril Islands

    19 Jan 1913 · 114 km away

    Limited damage (under $1M)

  4. 1918M7.8

    Kuril Islands

    8 Nov 1918 · 85 km away

    tsunami

  5. 1908M7.6

    Kuril Islands

    6 Nov 1908 · 182 km away

  6. 1847M7.5

    Kuril Islands

    21 Jun 1847 · 114 km away

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

Nearby trackers

Closest city pages