M4.6 Earthquake south of Africa — June 21, 2021
2021-06-21 18:11:07 UTC (2021-06-21) · approx. 8:11 PM UTC+2 local
Aftershock of the M5.7 mainshock.
On June 21, 2021 at 18:11 UTC, a magnitude 4.6 shallow crustal earthquake struck south of Africa, at a depth of 10.0 km and coordinates -48.3766°, 30.6372°.
Physical scale: An earthquake of magnitude 4.6 releases seismic energy equivalent to roughly 120 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 899 m — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.7 mainshock that occurred 6 days ago south of Africa. Since the mainshock, the USGS has recorded 1 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
Earthquake Details
30.6372°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.6 earthquake south of Africa?
The magnitude 4.6 earthquake that struck south of Africa on June 21, 2021 at 18:11 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 -48.3766°, 30.6372°, which is south of Africa.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.6 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.7 one earlier?
No. This magnitude 4.6 earthquake is an aftershock of the larger magnitude 5.7 mainshock that occurred earlier south of Africa. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Actions
Authoritative source: USGS event page (event ID: us7000eezm). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, June 21, 2021). M4.6 Earthquake south of Africa — June 21, 2021. Retrieved August 27, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000eezm/