M7.2 earthquake 38 km ESE of Severo-Kuril’sk, Russia

Wednesday, February 28, 1973, 06:37:49 UTC · 50.486°N, 156.584°E

A magnitude 7.2 earthquake struck 38 km ESE of Severo-Kuril’sk, Russia on Wednesday, February 28, 1973, 06:37:49 UTC, at a depth of 27.0 km (shallow). It is the strongest earthquake within 300 km since an M7.4 on October 31, 1916.

Magnitude: 7.2; Major · ms
Depth: 27 km; Shallow
Felt reports: 0; Did You Feel It?
Est. shaking: VII; Very 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

951 kilotons of TNT

That is about 63 times the Hiroshima bomb. It released about 1,995 times the energy of a magnitude 5.0.

Tectonic setting

150 km

from the nearest mapped plate boundary, between the Okhotsk and Pacific plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.

Depth: shallow

27 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 17 M2.5+ earthquakes within 200 km in the following 30 days; the largest was M6.1 on March 12, 1973. 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 244 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 13 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 100 recorded deaths. The most severe:

1737
Kamchatka
16 Oct 1737 · 121 km away
100 deathstsunami
1841M8.4
Off Kamchatka
17 May 1841 · 195 km away · intensity XI
Moderate damage ($1–5M)tsunami
1973M7.2
Kuril Islands, Hiroo, Urakawa
28 Feb 1973 · 2 km away · intensity VIII
Moderate damage ($1–5M)tsunami
1904M8.3
Off Kamchatka
25 Jun 1904 · 238 km away · intensity X
Limited damage (under $1M)tsunami
1904M8.1
Off Kamchatka
25 Jun 1904 · 238 km away · intensity X
Limited damage (under $1M)tsunami
1904M7.9
Off Kamchatka
27 Jun 1904 · 238 km away · intensity IX

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

Nearby trackers