3.3

M3.3 Earthquake in the Puerto Rico region — October 6, 2020

2020-10-06 23:18:47 UTC (2020-10-06) · approx. 7:18 PM UTC-4 local

Felt by 12 people across nearby locations.

MagnitudeM3.3(md)
Time23:18 UTC≈ 7:18 PM UTC-4
Depth7.0 kmshallow crustal
Coordinates17.926°, -66.891°
Felt by12DYFI responses
Status✓ Reviewed by USGS

On October 6, 2020 at 23:18 UTC, a magnitude 3.3 shallow crustal earthquake struck in the Puerto Rico region, at a depth of 7.0 km and coordinates 17.9261°, -66.8913°. This earthquake was detected by 22 seismic stations with moderate location accuracy and was assigned a USGS significance rating of 175, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 3.3 releases seismic energy equivalent to roughly 1.4 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 118 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

Map showing earthquake epicenter at 17.93°, -66.89°

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 12 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.

USGS DYFI community-reported intensity map for the M3.3 earthquake near Puerto Rico region

Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report

Earthquake Details

Magnitude
3.3 md
Depth
7.0 km
shallow crustal
Location
17.9261°N
-66.8913°E
Felt Reports
12
DYFI responses
Community Intensity
4.8
CDI from reports

Technical Information

Event ID
pr2020280015
Event Type
earthquake
Status
✓ Reviewed
Significance
175
Stations Used
22
Azimuthal Gap
211.0°
Min Station Distance
0.051°
RMS Residual
0.16 sec
Last Updated
2020-12-12 22:28:44 UTC

Common Questions

How strong was the magnitude 3.3 earthquake in the Puerto Rico region?

The magnitude 3.3 earthquake that struck in the Puerto Rico region on October 6, 2020 at 23:18 UTC had a depth of 7.0 km. For context, this was a minor earthquake typically detected only by instruments.

Where did the earthquake occur?

The earthquake epicenter was located at 17.9261°, -66.8913°, which is in the Puerto Rico region. View all earthquakes in Puerto Rico.

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.

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 3.3 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: pr2020280015). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2020, October 6, 2020). M3.3 Earthquake in the Puerto Rico region — October 6, 2020. Retrieved December 12, 2020 from https://www.earthquaketracker.org/earthquakes/event/pr2020280015/