Reviewed by USGS63y ago
M6.7 earthquake in South Sandwich Islands region
Tuesday, December 31, 1963, 17:37:34 UTC · 56.529°S, 26.064°W
A magnitude 6.7 earthquake struck in South Sandwich Islands region on Tuesday, December 31, 1963, 17:37:34 UTC, at a depth of 35.0 km (shallow). It is the strongest earthquake within 300 km since an M6.8 on January 30, 1963.
- Magnitude
- 6.7
- Strong · mw
- Depth
- 35 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 earthquake
In context
How big was it, and why here?
Energy released
175 kilotons of TNT
That is about 12 times the Hiroshima bomb. It released about 367 times the energy of a magnitude 5.0.
Tectonic setting
61 km
from the nearest mapped plate boundary, between the Sandwich and South American plates. Earthquakes cluster along boundaries like this one, where plates collide, pull apart or slide past each other.
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 100 km
USGS has not published any M2.5+ earthquake within 100 km in the 30 days after this event.
Regional history
Past M5+ earthquakes within 300 km
USGS lists 49 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.11929 South Sandwich Islands EarthquakeJune 27, 1929 · 241 km NW of this epicenter
- 7.1South Sandwich Islands regionSeptember 8, 1961 · 82 km W of this epicenter
- 6.9South Sandwich Islands regionAugust 18, 1930 · 144 km NW of this epicenter
- 6.9South Sandwich Islands regionSeptember 13, 1921 · 190 km NW of this epicenter
- 6.8South Sandwich Islands regionNovember 2, 1943 · 26 km S of this epicenter
- 6.8South Sandwich Islands regionJanuary 30, 1963 · 188 km NW of this epicenter
- 6.6South Sandwich Islands regionDecember 6, 1929 · 292 km NW of this epicenter
- 6.6South Sandwich Islands regionJuly 21, 1933 · 276 km W of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 3 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 1929M8.1
South Sandwich Islands
27 Jun 1929 · 241 km away
- 1961M7.7
South Sandwich Islands
5 Sep 1961 · 173 km away
- 1961M7.7
South Sandwich Islands
8 Sep 1961 · 81 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.