M5.5 Earthquake southwest of Africa — August 3, 2021
2021-08-03 06:43:00 UTC (2021-08-03) · approx. 7:43 AM UTC+1 local
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On August 3, 2021 at 06:43 UTC, a magnitude 5.5 shallow crustal earthquake struck southwest of Africa, at a depth of 10.0 km and coordinates -52.7494°, 18.4678°. 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 5.5 releases seismic energy equivalent to roughly 3 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 3.8 km — a useful intuition for the size of the slip patch on the fault.
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
18.4678°E
Technical Information
Common Questions
How strong was the magnitude 5.5 earthquake southwest of Africa?
The magnitude 5.5 earthquake that struck southwest of Africa on August 3, 2021 at 06:43 UTC had a depth of 10.0 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -52.7494°, 18.4678°, which is southwest of Africa.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.5 earthquakes can continue for days to weeks and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us6000f1sc). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, August 3, 2021). M5.5 Earthquake southwest of Africa — August 3, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000f1sc/