M3.8 Earthquake 72 km NNW of San Antonio, Puerto Rico — October 21, 2023
2023-10-21 22:37:35 UTC (2023-10-21) · approx. 6:37 PM UTC-4 local
On October 21, 2023 at 22:37 UTC, a magnitude 3.8 intermediate depth earthquake struck 72 km NNW of San Antonio, Puerto Rico, at a depth of 87.0 km and coordinates 19.1248°, -67.2921°.
Physical scale: An earthquake of magnitude 3.8 releases seismic energy equivalent to roughly 6.6 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 237 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-67.2921°E
Technical Information
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Common Questions
How strong was the magnitude 3.8 earthquake near San Antonio, Puerto Rico?
The magnitude 3.8 earthquake that struck 72 km NNW of San Antonio, Puerto Rico on October 21, 2023 at 22:37 UTC had a depth of 87.0 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 3.8 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.8 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: pr2023294001). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, October 21, 2023). M3.8 Earthquake 72 km NNW of San Antonio, Puerto Rico — October 21, 2023. Retrieved December 26, 2023 from https://www.earthquaketracker.org/earthquakes/event/pr2023294001/