M4.5 Earthquake 16 km S of Angra do Heroísmo, Portugal — September 25, 2023
2023-09-25 16:47:25 UTC (2023-09-25) · approx. 2:47 PM UTC-2 local
On September 25, 2023 at 16:47 UTC, a magnitude 4.5 shallow crustal earthquake struck 16 km S of Angra do Heroísmo, Portugal, at a depth of 10.0 km and coordinates 38.5081°, -27.2421°. This earthquake was detected by 23 seismic stations with good location accuracy and was assigned a USGS significance rating of 312, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.5 releases seismic energy equivalent to roughly 85 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 767 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-27.2421°E
Technical Information
Common Questions
How strong was the magnitude 4.5 earthquake near Angra do Heroísmo, Portugal?
The magnitude 4.5 earthquake that struck 16 km S of Angra do Heroísmo, Portugal on September 25, 2023 at 16:47 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 38.5081°, -27.2421°, which is 16 km S of Angra do Heroísmo, Portugal.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 earthquakes can continue for several days and gradually diminish over time.
Authoritative source: USGS event page (event ID: us6000lbq0). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, September 25, 2023). M4.5 Earthquake 16 km S of Angra do Heroísmo, Portugal — September 25, 2023. Retrieved December 9, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000lbq0/