3.1

M3.1 Earthquake 0 km NNE of Central Aguirre, Puerto RicoSeptember 9, 2021

2021-09-09 22:31:53 UTC (2021-09-09) · approx. 6:31 PM UTC-4 local

MagnitudeM3.1(md)
Time22:31 UTC6:31 PM UTC-4
Depth12.0 kmshallow crustal
Coordinates17.956°, -66.222°
Felt by3DYFI responses
Status✓ Reviewed by USGS

On September 9, 2021 at 22:31 UTC, a magnitude 3.1 shallow crustal earthquake struck 0 km NNE of Central Aguirre, Puerto Rico, at a depth of 12.0 km and coordinates 17.9563°, -66.2218°.

Physical scale: An earthquake of magnitude 3.1 releases seismic energy equivalent to roughly 722 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 86 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 17.96°, -66.22°

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 3 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 M3.1 earthquake near 0 km NNE of Central Aguirre, Puerto Rico

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

Earthquake Details

Magnitude
3.1 md
Depth
12.0 km
shallow crustal
Location
17.9563°N
-66.2218°E
Felt Reports
3
DYFI responses
Community Intensity
3.4
CDI from reports

Technical Information

Event ID
pr2021252012
Event Type
earthquake
Status
✓ Reviewed
Significance
151
Stations Used
9
Azimuthal Gap
199.0°
Min Station Distance
0.115°
RMS Residual
0.11 sec
Last Updated
2022-08-08 14:46:50 UTC

Common Questions

How strong was the magnitude 3.1 earthquake near Central Aguirre, Puerto Rico?

The magnitude 3.1 earthquake that struck 0 km NNE of Central Aguirre, Puerto Rico on September 9, 2021 at 22:31 UTC had a depth of 12.0 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.

Understanding This Data

Magnitude 3.1 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: pr2021252012). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, September 9, 2021). M3.1 Earthquake 0 km NNE of Central Aguirre, Puerto RicoSeptember 9, 2021. Retrieved August 8, 2022 from https://www.earthquaketracker.org/earthquakes/event/pr2021252012/