M3.1 Earthquake 43 km NW of San Antonio, Puerto Rico — August 23, 2026
2026-08-23 08:57:13 UTC (2 hours ago) · approx. 4:57 AM UTC-4 local
On August 23, 2026 at 08:57 UTC, a magnitude 3.1 shallow crustal earthquake struck 43 km NW of San Antonio, Puerto Rico, at a depth of 5.0 km and coordinates 18.7888°, -67.3723°.
Physical scale: An earthquake of magnitude 3.1 releases seismic energy equivalent to roughly 651 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 82 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-67.3723°E
Technical Information
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Common Questions
How strong was the magnitude 3.1 earthquake near San Antonio, Puerto Rico?
The magnitude 3.1 earthquake that struck 43 km NW of San Antonio, Puerto Rico on August 23, 2026 at 08:57 UTC had a depth of 5.0 km. For context, this was a minor earthquake typically detected only by instruments.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.1 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.1 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: pr71529488). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, August 23, 2026). M3.1 Earthquake 43 km NW of San Antonio, Puerto Rico — August 23, 2026. Retrieved August 23, 2026 from https://www.earthquaketracker.org/earthquakes/event/pr71529488/