Reviewed by USGSRussia80y ago
M6.4 earthquake 169 km SE of Shikotan, Russia
Saturday, December 21, 1946, 20:20:29 UTC · 42.908°N, 148.413°E
A magnitude 6.4 earthquake struck 169 km SE of Shikotan, Russia on Saturday, December 21, 1946, 20:20:29 UTC, at a depth of 25.0 km (shallow). It is the strongest earthquake within 300 km since an M6.8 on December 21, 1946.
- Magnitude
- 6.4
- Strong · mw
- Depth
- 25 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 earthquakeDashed circle: 100 km aftershock search area
In context
How big was it, and why here?
Energy released
58 kilotons of TNT
That is about 4 times the Hiroshima bomb. It released about 122 times the energy of a magnitude 5.0.
Tectonic setting
31 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
25 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 lists 2 M2.5+ earthquakes within 100 km in the following 30 days; the largest was M6.7 on January 3, 1947. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 101 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 7.542 km SSW of Shikotan, RussiaSeptember 11, 1935 · 156 km W of this epicenter
- 7.4170 km ESE of Kuril’sk, RussiaFebruary 21, 1937 · 201 km NE of this epicenter
- 7.3Kuril IslandsApril 5, 1901 · 183 km N of this epicenter
- 7.2134 km E of Shikotan, RussiaDecember 21, 1946 · 83 km N of this epicenter
- 7.2268 km SE of Kuril’sk, RussiaMay 22, 1910 · 149 km NE of this epicenter
- 7.1Off the coast of Hokkaido, JapanDecember 25, 1900 · 197 km W of this epicenter
- 7.1147 km E of Kuril’sk, RussiaOctober 18, 1920 · 296 km N of this epicenter
- 7.0Kuril IslandsNovember 24, 1900 · 74 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 15 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700, which together caused about 46 recorded deaths. The most severe:
- 1843M8.4
Hokkaido: Yezo, Kushiro, Nemuro
25 Apr 1843 · 222 km away
45 deathsModerate damage ($1–5M)tsunami
- 1894M7.9
Off Coast Of Honshu
22 Mar 1894 · 202 km away · intensity IX
1 deathModerate damage ($1–5M)tsunami
- 1904M7.6
Hokkaido
18 Mar 1904 · 218 km away · intensity X
Limited damage (under $1M)
- 1937M7.6
Kuril Islands
21 Feb 1937 · 194 km away
Limited damage (under $1M)
- 1839M7.3
Se. Hokkaido Island, Japan
1 May 1839 · 283 km away
Limited damage (under $1M)tsunami
- 1900M7.9
Kuril Islands
25 Dec 1900 · 197 km away · intensity IX
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.