M3.1 Earthquake 9 km S of Lares, Puerto Rico — September 12, 2021
2021-09-12 16:48:25 UTC (2021-09-12) · approx. 12:48 PM UTC-4 local
On September 12, 2021 at 16:48 UTC, a magnitude 3.1 shallow crustal earthquake struck 9 km S of Lares, Puerto Rico, at a depth of 29.0 km and coordinates 18.2120°, -66.8610°.
Physical scale: An earthquake of magnitude 3.1 releases seismic energy equivalent to roughly 801 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 90 m — a useful intuition for the size of the slip patch on the fault.
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 1 citizen response 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
-66.8610°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 3.1 earthquake near Lares, Puerto Rico?
The magnitude 3.1 earthquake that struck 9 km S of Lares, Puerto Rico on September 12, 2021 at 16:48 UTC had a depth of 29.0 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.
Actions
Understanding This Data
Magnitude 3.1 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: pr2021255004). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, September 12, 2021). M3.1 Earthquake 9 km S of Lares, Puerto Rico — September 12, 2021. Retrieved August 8, 2022 from https://www.earthquaketracker.org/earthquakes/event/pr2021255004/