M3.3 Earthquake 46 km NNW of San Antonio, Puerto Rico — December 31, 2020
2020-12-31 21:18:00 UTC (2020-12-31) · approx. 5:18 PM UTC-4 local
On December 31, 2020 at 21:18 UTC, a magnitude 3.3 shallow crustal earthquake struck 46 km NNW of San Antonio, Puerto Rico, at a depth of 5.0 km and coordinates 18.8988°, -67.2190°.
Physical scale: An earthquake of magnitude 3.3 releases seismic energy equivalent to roughly 1.5 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 122 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-67.2190°E
Technical Information
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Common Questions
How strong was the magnitude 3.3 earthquake near San Antonio, Puerto Rico?
The magnitude 3.3 earthquake that struck 46 km NNW of San Antonio, Puerto Rico on December 31, 2020 at 21:18 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 3.3 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.3 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: pr2020366008). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2020, December 31, 2020). M3.3 Earthquake 46 km NNW of San Antonio, Puerto Rico — December 31, 2020. Retrieved March 6, 2021 from https://www.earthquaketracker.org/earthquakes/event/pr2020366008/