M3.9 Earthquake 68 km N of San Juan, Puerto Rico — June 10, 2021
2021-06-10 17:42:16 UTC (2021-06-10) · approx. 1:42 PM UTC-4 local
Felt by 25 people across nearby locations.
On June 10, 2021 at 17:42 UTC, a magnitude 3.9 shallow crustal earthquake struck 68 km N of San Juan, Puerto Rico, at a depth of 6.0 km and coordinates 19.0816°, -66.1018°. This earthquake was detected by 20 seismic stations with moderate location accuracy and was assigned a USGS significance rating of 237, placing it among routine seismic activity.
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.
The epicenter is located in Puerto Rico, a region characterized by the Puerto Rico Trench oblique subduction zone and the Muertos Trough, with complex Caribbean–North American plate interactions. The nearest mapped fault system is the Puerto Rico Trench. View all earthquakes in Puerto Rico.
Learn more: Magnitude scale · Aftershock sequences
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 25 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
-66.1018°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.9 earthquake near San Juan, Puerto Rico?
The magnitude 3.9 earthquake that struck 68 km N of San Juan, Puerto Rico on June 10, 2021 at 17:42 UTC had a depth of 6.0 km. For context, this was a minor earthquake typically detected only by instruments.
Where did the earthquake occur?
The earthquake epicenter was located at 19.0816°, -66.1018°, which is 68 km N of San Juan, Puerto Rico. View all earthquakes in Puerto Rico.
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.
Has Puerto Rico had earthquakes this big before?
The largest recorded earthquake in Puerto Rico was the M7.3 offshore earthquake of October 11, 1918. Today's magnitude 3.9 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: pr2021161006). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, June 10, 2021). M3.9 Earthquake 68 km N of San Juan, Puerto Rico — June 10, 2021. Retrieved August 24, 2021 from https://www.earthquaketracker.org/earthquakes/event/pr2021161006/