M5.8 Earthquake south of Africa — September 25, 2021
2021-09-25 05:21:32 UTC (2021-09-25) · approx. 7:21 AM UTC+2 local
Felt by 2 people across nearby locations. 0
On September 25, 2021 at 05:21 UTC, a magnitude 5.8 shallow crustal earthquake struck south of Africa, at a depth of 7.0 km and coordinates -53.4197°, 23.5583°.0 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 5.8 releases seismic energy equivalent to roughly 8 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 6.1 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
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 2 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
23.5583°E
Technical Information
Common Questions
How strong was the magnitude 5.8 earthquake south of Africa?
The magnitude 5.8 earthquake that struck south of Africa on September 25, 2021 at 05:21 UTC had a depth of 7.0 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -53.4197°, 23.5583°, which is south of Africa.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.8 earthquakes can continue for days to weeks and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us7000feai). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, September 25, 2021). M5.8 Earthquake south of Africa — September 25, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000feai/