3.4

M3.4 Earthquake 79 km NNE of Luquillo, Puerto RicoAugust 4, 2025

2025-08-04 23:14:06 UTC (2025-08-04) · approx. 7:14 PM UTC-4 local

MagnitudeM3.4(md)
Time23:14 UTC7:14 PM UTC-4
Depth49.0 kmshallow crustal
Coordinates19.023°, -65.397°
Felt by2DYFI responses
Status✓ Reviewed by USGS

On August 4, 2025 at 23:14 UTC, a magnitude 3.4 shallow crustal earthquake struck 79 km NNE of Luquillo, Puerto Rico, at a depth of 49.0 km and coordinates 19.0225°, -65.3968°.

Physical scale: An earthquake of magnitude 3.4 releases seismic energy equivalent to roughly 2.0 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 138 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 19.02°, -65.40°

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 2 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 M3.4 earthquake near 79 km NNE of Luquillo, Puerto Rico

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

Earthquake Details

Magnitude
3.4 md
Depth
49.0 km
shallow crustal
Location
19.0225°N
-65.3968°E
Felt Reports
2
DYFI responses
Community Intensity
2.7
CDI from reports

Technical Information

Event ID
pr71491533
Event Type
earthquake
Status
✓ Reviewed
Significance
180
Stations Used
20
Azimuthal Gap
237.0°
Min Station Distance
0.786°
RMS Residual
0.24 sec
Last Updated
2025-10-17 22:51:42 UTC

Common Questions

How strong was the magnitude 3.4 earthquake near Luquillo, Puerto Rico?

The magnitude 3.4 earthquake that struck 79 km NNE of Luquillo, Puerto Rico on August 4, 2025 at 23:14 UTC had a depth of 49.0 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 3.4 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.4 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: pr71491533). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2025, August 4, 2025). M3.4 Earthquake 79 km NNE of Luquillo, Puerto RicoAugust 4, 2025. Retrieved October 17, 2025 from https://www.earthquaketracker.org/earthquakes/event/pr71491533/