M7.8 earthquake 217 km ESE of Kuril’sk, Russia

Sunday, October 20, 1963, 00:53:12 UTC · 44.726°N, 150.547°E

A magnitude 7.8 earthquake struck 217 km ESE of Kuril’sk, Russia on Sunday, October 20, 1963, 00:53:12 UTC, at a depth of 28.2 km (shallow). It is the strongest earthquake within 300 km since an M8.5 on October 13, 1963.

Magnitude: 7.8; Major · mw
Depth: 28 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

7.6 megatons of TNT

That is about 502 times the Hiroshima bomb. It released about 15,849 times the energy of a magnitude 5.0.

Tectonic setting

40 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

28 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 10 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.5 on November 10, 1963. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.

Time after the mainshock on a logarithmic scale (first hours stretched), magnitude on the vertical axis. M2.5+ events from USGS.

Regional history

Past M5+ earthquakes within 300 km

USGS lists 243 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 21 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 35 recorded deaths. The most severe:

1918M8.3
Kuril Islands
7 Sep 1918 · 114 km away
23 deathsModerate damage ($1–5M)tsunami
1780M7.5
Kuril Islands
29 Jun 1780 · 82 km away
12 deathsLimited damage (under $1M)tsunami
1958M8.3
Kuril Islands
6 Nov 1958 · 160 km away · intensity X
Moderate damage ($1–5M)tsunami
1963M8.5
Kuril Islands
13 Oct 1963 · 59 km away · intensity IX
Limited damage (under $1M)tsunami
1937M7.6
Kuril Islands
21 Feb 1937 · 94 km away
Limited damage (under $1M)
1913M7.5
Kuril Islands
19 Jan 1913 · 182 km away
Limited damage (under $1M)

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

Nearby trackers