M6.0 Earthquake in the South Sandwich Islands region — December 16, 2021
2021-12-16 21:14:46 UTC (2021-12-16) · approx. 7:14 PM UTC-2 local
On December 16, 2021 at 21:14 UTC, a magnitude 6.0 shallow crustal earthquake struck in the South Sandwich Islands region, at a depth of 15.0 km and coordinates -60.1754°, -23.8375°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected.
Physical scale: An earthquake of magnitude 6.0 releases seismic energy equivalent to roughly 15 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 8.3 km — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in South Sandwich Islands, a region characterized by the South Sandwich Trench, one of Earth's most remote subduction zones.
Learn more: Magnitude scale · Aftershock sequences
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Earthquake Details
-23.8375°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 6.0 earthquake in the South Sandwich Islands region?
The magnitude 6.0 earthquake that struck in the South Sandwich Islands region on December 16, 2021 at 21:14 UTC had a depth of 15.0 km. For context, this was a strong earthquake capable of causing significant damage.
Where did the earthquake occur?
The earthquake epicenter was located at -60.1754°, -23.8375°, which is in the South Sandwich Islands region.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 6.0 earthquakes can continue for weeks to months and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us6000gcxa). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, December 16, 2021). M6.0 Earthquake in the South Sandwich Islands region — December 16, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000gcxa/