M4.3 Earthquake 27 km S of São Mateus, Portugal — September 25, 2023
2023-09-25 16:44:24 UTC (2023-09-25) · approx. 2:44 PM UTC-2 local
On September 25, 2023 at 16:44 UTC, a magnitude 4.3 shallow crustal earthquake struck 27 km S of São Mateus, Portugal, at a depth of 10.0 km and coordinates 38.4100°, -27.3065°.
Physical scale: An earthquake of magnitude 4.3 releases seismic energy equivalent to roughly 43 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 558 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-27.3065°E
Technical Information
Common Questions
How strong was the magnitude 4.3 earthquake near São Mateus, Portugal?
The magnitude 4.3 earthquake that struck 27 km S of São Mateus, Portugal on September 25, 2023 at 16:44 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.3 earthquakes can continue for several days and gradually diminish over time.
Actions
Understanding This Data
Magnitude 4.3 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000lbq4). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, September 25, 2023). M4.3 Earthquake 27 km S of São Mateus, Portugal — September 25, 2023. Retrieved December 9, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000lbq4/