Reviewed by USGS4y ago
M5.3 earthquake in South Sandwich Islands region
Monday, November 22, 2021, 01:22:52 UTC · 57.936°S, 25.675°W
A magnitude 5.3 earthquake struck in South Sandwich Islands region on Monday, November 22, 2021, 01:22:52 UTC, at a depth of 48.9 km (shallow). The USGS PAGER alert is green: low likelihood of casualties and damage. It is the strongest earthquake within 300 km since an M5.4 on November 6, 2021.
- Magnitude
- 5.3
- Moderate · mww
- Depth
- 49 km
- Shallow
- Felt reports
- 0
- Did You Feel It?
- Est. shaking
- III
- Weak (ShakeMap)
- PAGER alert
- Green
- Impact estimate
- Tsunami
- No flag
- USGS feed
Outlined circle: this earthquakeDashed circle: 75 km aftershock search areaColoured lines: estimated shaking intensity (USGS ShakeMap)
In context
How big was it, and why here?
Energy released
1 kilotons of TNT
That is about 1/11 of the Hiroshima bomb. It released about 3 times the energy of a magnitude 5.0.
Tectonic setting
101 km
from the nearest mapped plate boundary, between the Sandwich and South American plates. Earthquakes this far from a boundary happen on faults inside a plate, often less frequently but sometimes strongly.
Depth: shallow
49 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 populated area was estimated to feel noticeable shaking.
After the main event
Aftershocks within 75 km
USGS lists 21 M2.5+ earthquakes within 75 km in the following 30 days; the largest was M5.8 on December 7, 2021. Most nearby activity right after a large earthquake is aftershocks, which usually become less frequent over days and weeks.
- 4.6South Sandwich Islands region4y ago · 23 km E of this epicenter
- 4.6South Sandwich Islands region4y ago · 67 km SE of this epicenter
- 5.0South Sandwich Islands region4y ago · 23 km E of this epicenter
- 4.6South Sandwich Islands region4y ago · 12 km NW of this epicenter
- 4.5South Sandwich Islands region4y ago · 25 km E of this epicenter
- 5.0South Sandwich Islands region4y ago · 37 km E of this epicenter
- 4.4South Sandwich Islands region4y ago · 63 km N of this epicenter
- 5.0South Sandwich Islands region4y ago · 35 km SW of this epicenter
Regional history
Past M5+ earthquakes within 300 km
USGS lists 1,814 M5.0+ earthquakes within 300 km before this one (catalog from 1900; older records are less complete). The strongest:
- 8.12021 South Sandwich Islands EarthquakeAugust 12, 2021 · 54 km SE of this epicenter
- 7.8South Sandwich Islands regionMay 26, 1964 · 216 km NW of this epicenter
- 7.5South Sandwich Islands regionAugust 12, 2021 · 56 km NE of this epicenter
- 7.5South Sandwich Islands regionAugust 28, 1933 · 270 km S of this epicenter
- 7.3South Sandwich Islands regionSeptember 1, 1961 · 162 km SW of this epicenter
- 7.2South Sandwich Islands regionNovember 15, 1910 · 165 km SE of this epicenter
- 7.2South Sandwich Islands regionDecember 27, 1991 · 213 km N of this epicenter
- 7.2South Sandwich Islands regionMay 28, 2016 · 203 km NW of this epicenter
History · NOAA
Deadliest earthquakes in this area
NOAA’s significant-earthquake database lists 5 damaging, deadly or tsunami-generating earthquakes within 300 km of this epicenter since 1700. The most severe:
- 2021M8.1
South Sandwich Islands
12 Aug 2021 · 57 km away
tsunami
- 1961M7.7
South Sandwich Islands
5 Sep 1961 · 78 km away
- 1961M7.7
South Sandwich Islands
8 Sep 1961 · 210 km away
- 1961M7.5
South Sandwich Islands
1 Sep 1961 · 198 km away
- 2021M7.5
South Sandwich Islands
12 Aug 2021 · 48 km away
NOAA NCEI Global Significant Earthquake Database. Historical figures are estimates; older records are incomplete.