M4.9 Earthquake east of the South Sandwich Islands — April 3, 2021
2021-04-03 11:11:29 UTC (2021-04-03) · approx. 10:11 AM UTC-1 local
On April 3, 2021 at 11:11 UTC, a magnitude 4.9 shallow crustal earthquake struck east of the South Sandwich Islands, at a depth of 10.0 km and coordinates -57.8496°, -7.6118°.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 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
Earthquake Details
-7.6118°E
Technical Information
Common Questions
How strong was the magnitude 4.9 earthquake east of the South Sandwich Islands?
The magnitude 4.9 earthquake that struck east of the South Sandwich Islands on April 3, 2021 at 11:11 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -57.8496°, -7.6118°, which is east of the South Sandwich Islands.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 earthquakes can continue for several days and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us6000dyr1). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, April 3, 2021). M4.9 Earthquake east of the South Sandwich Islands — April 3, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000dyr1/