M3.9 Earthquake 86 km N of Culebra, Puerto Rico — July 6, 2021
2021-07-06 18:40:55 UTC (2021-07-06) · approx. 2:40 PM UTC-4 local
On July 6, 2021 at 18:40 UTC, a magnitude 3.9 shallow crustal earthquake struck 86 km N of Culebra, Puerto Rico, at a depth of 49.0 km and coordinates 19.0856°, -65.2585°.
Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 9.6 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 282 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-65.2585°E
Technical Information
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Common Questions
How strong was the magnitude 3.9 earthquake near Culebra, Puerto Rico?
The magnitude 3.9 earthquake that struck 86 km N of Culebra, Puerto Rico on July 6, 2021 at 18:40 UTC had a depth of 49.0 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 3.9 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.9 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: pr2021187009). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, July 6, 2021). M3.9 Earthquake 86 km N of Culebra, Puerto Rico — July 6, 2021. Retrieved September 10, 2021 from https://www.earthquaketracker.org/earthquakes/event/pr2021187009/