M3.9 Earthquake 3 km NNW of Fochville, South Africa — July 31, 2021
2021-07-31 22:43:01 UTC (2021-07-31) · approx. 12:43 AM UTC+2 local
Felt by 13 people across nearby locations.
On July 31, 2021 at 22:43 UTC, a magnitude 3.9 shallow crustal earthquake struck 3 km NNW of Fochville, South Africa, at a depth of 5.0 km and coordinates -26.4652°, 27.4773°.
Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 11 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 296 m — a useful intuition for the size of the slip patch on the fault.
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 13 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
27.4773°E
Technical Information
Common Questions
How strong was the magnitude 3.9 earthquake near Fochville, South Africa?
The magnitude 3.9 earthquake that struck 3 km NNW of Fochville, South Africa on July 31, 2021 at 22:43 UTC had a depth of 5.0 km. For context, this was a minor earthquake typically detected only by instruments.
Where did the earthquake occur?
The earthquake epicenter was located at -26.4652°, 27.4773°, which is 3 km NNW of Fochville, South Africa.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.9 earthquakes can continue for several days and gradually diminish over time.
Authoritative source: USGS event page (event ID: us6000f138). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, July 31, 2021). M3.9 Earthquake 3 km NNW of Fochville, South Africa — July 31, 2021. Retrieved October 14, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000f138/