3.5

M3.5 Earthquake 5 km S of Guánica, Puerto Rico — September 6, 2020

2020-09-06 21:38:46 UTC (2020-09-06) · approx. 5:38 PM UTC-4 local

MagnitudeM3.5(md)
Time21:38 UTC≈ 5:38 PM UTC-4
Depth9.0 kmshallow crustal
Coordinates17.919°, -66.907°
Felt by4DYFI responses· max MMI 2.9
Status✓ Reviewed by USGS

On September 6, 2020 at 21:38 UTC, a magnitude 3.5 shallow crustal earthquake struck 5 km S of Guánica, Puerto Rico, at a depth of 9.0 km and coordinates 17.9190°, -66.9068°. The earthquake was reported felt by 4 peopleacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 2.9 (weak).

Physical scale: An earthquake of magnitude 3.5 releases seismic energy equivalent to roughly 2.9 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 162 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 17.92°, -66.91°

ShakeMap — predicted shaking intensity

Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.

USGS ShakeMap intensity contours for the M3.5 earthquake near 5 km S of Guánica, Puerto Rico

Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 4 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 M3.5 earthquake near 5 km S of Guánica, Puerto Rico

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

Earthquake Details

Magnitude
3.5 md
Depth
9.0 km
shallow crustal
Location
17.9190°N
-66.9068°E
Felt Reports
4
DYFI responses
Intensity (MMI)
2.9
weak
Community Intensity
3.8
CDI from reports

Technical Information

Event ID
pr2020250015
Event Type
earthquake
Status
✓ Reviewed
Significance
192
Stations Used
21
Azimuthal Gap
217.0°
Min Station Distance
0.063°
RMS Residual
0.16 sec
Last Updated
2020-11-17 19:44:48 UTC

Common Questions

How strong was the magnitude 3.5 earthquake near Guánica, Puerto Rico?

The magnitude 3.5 earthquake that struck 5 km S of Guánica, Puerto Rico on September 6, 2020 at 21:38 UTC had a depth of 9.0 km. It was felt by 4 people with maximum shaking intensity of MMI 2.9 (weak). 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 3.5 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.5 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: pr2020250015). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2020, September 6, 2020). M3.5 Earthquake 5 km S of Guánica, Puerto Rico — September 6, 2020. Retrieved November 17, 2020 from https://www.earthquaketracker.org/earthquakes/event/pr2020250015/