Reviewed by USGS10y ago
M4.2 earthquake in South Sandwich Islands region
Sunday, July 31, 2016, 10:09:09 UTC · 55.986°S, 27.124°W
A magnitude 4.2 earthquake struck in South Sandwich Islands region on Sunday, July 31, 2016, 10:09:09 UTC, at a depth of 43.7 km (shallow).
- Magnitude
- 4.2
- Light · mb
- Depth
- 44 km
- Shallow
- Felt reports
- 0
- Max intensity I
- Est. shaking
- —
- No ShakeMap
- PAGER alert
- None
- Not issued
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 50 km aftershock search area
In context
How big was it, and why here?
Energy released
30 tons of TNT
That is about 1/500 of the Hiroshima bomb. A magnitude 5.0 releases about 16 times more energy.
Tectonic setting
75 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
44 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 50 km
USGS lists 10 M2.5+ earthquakes within 50 km in the following 30 days; the largest was M5.9 on July 31, 2016. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.5South Sandwich Islands region10y ago · 13 km E of this epicenter
- 5.4South Sandwich Islands region10y ago · 37 km SE of this epicenter
- 4.5South Sandwich Islands region10y ago · 38 km SW of this epicenter
- 4.5South Sandwich Islands region10y ago · 31 km N of this epicenter
- 4.6South Sandwich Islands region10y ago · 34 km NE of this epicenter
- 4.5South Sandwich Islands region10y ago · 27 km SE of this epicenter
- 4.6South Sandwich Islands region10y ago · 32 km NE of this epicenter
- 5.1South Sandwich Islands region10y ago · 23 km N of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 1,076 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 · 155 km NW of this epicenter
- 7.8South Sandwich Islands regionMay 26, 1964 · 50 km SW of this epicenter
- 7.2South Sandwich Islands regionDecember 27, 1991 · 116 km E of this epicenter
- 7.2South Sandwich Islands regionMay 28, 2016 · 31 km S of this epicenter
- 7.1South Sandwich Islands regionSeptember 8, 1961 · 41 km S of this epicenter
- 6.9South Sandwich Islands regionAugust 18, 1930 · 58 km W of this epicenter
- 6.9South Sandwich Islands regionSeptember 13, 1921 · 104 km W of this epicenter
- 6.9South Sandwich Islands regionSeptember 6, 2004 · 135 km NW 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 · 155 km away
- 1961M7.7
South Sandwich Islands
5 Sep 1961 · 224 km away
- 1961M7.7
South Sandwich Islands
8 Sep 1961 · 32 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.