M4.9 Earthquake near southern Mid-Atlantic Ridge — October 18, 2021
2021-10-18 21:28:26 UTC (2021-10-18) · approx. 8:28 PM UTC-1 local
On October 18, 2021 at 21:28 UTC, a magnitude 4.9 shallow crustal earthquake struck near southern Mid-Atlantic Ridge, at a depth of 10.0 km and coordinates -48.9786°, -8.5069°.
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.
Earthquake Details
-8.5069°E
Technical Information
Common Questions
How strong was the magnitude 4.9 earthquake near southern Mid-Atlantic Ridge?
The magnitude 4.9 earthquake that struck near southern Mid-Atlantic Ridge on October 18, 2021 at 21:28 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 -48.9786°, -8.5069°, which is near southern Mid-Atlantic Ridge.
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: us6000fwqr). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, October 18, 2021). M4.9 Earthquake near southern Mid-Atlantic Ridge — October 18, 2021. Retrieved December 25, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000fwqr/