3.3

M3.3 Earthquake 70 km N of Culebra, Puerto RicoOctober 9, 2021

2021-10-09 20:17:40 UTC (2021-10-09) · approx. 4:17 PM UTC-4 local

MagnitudeM3.3(md)
Time20:17 UTC4:17 PM UTC-4
Depth24.0 kmshallow crustal
Coordinates18.943°, -65.281°
Felt by1DYFI response
Status✓ Reviewed by USGS

On October 9, 2021 at 20:17 UTC, a magnitude 3.3 shallow crustal earthquake struck 70 km N of Culebra, Puerto Rico, at a depth of 24.0 km and coordinates 18.9431°, -65.2806°.

Physical scale: An earthquake of magnitude 3.3 releases seismic energy equivalent to roughly 1.2 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 109 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 18.94°, -65.28°

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.

USGS DYFI community-reported intensity map for the M3.3 earthquake near 70 km N of Culebra, Puerto Rico

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

Earthquake Details

Magnitude
3.3 md
Depth
24.0 km
shallow crustal
Location
18.9431°N
-65.2806°E
Felt Reports
1
DYFI responses
Community Intensity
2.0
CDI from reports

Technical Information

Event ID
pr2021282008
Event Type
earthquake
Status
✓ Reviewed
Significance
165
Stations Used
13
Azimuthal Gap
293.0°
Min Station Distance
0.636°
RMS Residual
0.13 sec
Last Updated
2021-10-10 00:27:46 UTC

Common Questions

How strong was the magnitude 3.3 earthquake near Culebra, Puerto Rico?

The magnitude 3.3 earthquake that struck 70 km N of Culebra, Puerto Rico on October 9, 2021 at 20:17 UTC had a depth of 24.0 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.

Understanding This Data

Magnitude 3.3 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: pr2021282008). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, October 9, 2021). M3.3 Earthquake 70 km N of Culebra, Puerto RicoOctober 9, 2021. Retrieved October 10, 2021 from https://www.earthquaketracker.org/earthquakes/event/pr2021282008/