QuakeIndex

Earthquake · reviewed by a seismologist

M 4.0md

105 km N of Suárez, Puerto Rico

Yes. A magnitude 4.0 earthquake was recorded 105 km N of Suárez, Puerto Rico, at 5:26 am AST on 23 September 2025 (09:26 UTC), 9.0 km deep. 4 people have reported feeling it to USGS.

· 9.0 km deep · released about 15 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Loíza Municipio 106 kmFajardo Municipio 111 kmRío Grande Municipio 112 kmCarolina Municipio 112 kmSan Juan Municipio 112 kmLuquillo Municipio 112 kmCataño Municipio 112 kmToa Baja Municipio 113 kmDorado Municipio 115 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
Magnitude
M 4.0 (md)
Depth
9.0 km below the surface
Felt
4 reports · strongest reported intensity III
Nearest
Loíza Municipio, 106 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 340 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 96 km (60 mi) from the epicentre. Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

How big was it?

This earthquake released about 15 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 11,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 500× the energy of this one
  3. Magna, Utah 2020 M 5.7 350× the energy of this one
  4. This earthquake M 4.0 about 15 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 32× more

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

The largest earthquake within 50 km since 2016 was M 4.4 on 2023-02-28 — about 4.6 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.1 122 km NNE of Vieques, Puerto Rico · 45 km E of this epicentre
  2. 5.1 92 km N of Suárez, Puerto Rico · 13 km S of this epicentre
  3. 5.0 73 km NNE of Vieques, Puerto Rico · 49 km SSE of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 19.3780, -65.7395. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Loíza Municipio, PR 106 km (66 mi) SSW earthquakes near Loíza Municipio
Fajardo Municipio, PR 111 km (69 mi) S earthquakes near Fajardo Municipio
Río Grande Municipio, PR 112 km (69 mi) S earthquakes near Río Grande Municipio
Carolina Municipio, PR 112 km (69 mi) SSW earthquakes near Carolina Municipio
San Juan Municipio, PR 112 km (69 mi) SSW earthquakes near San Juan Municipio
Luquillo Municipio, PR 112 km (70 mi) S earthquakes near Luquillo Municipio

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

37 earthquakes have been recorded within 50 km since this one.

  1. 3.0 60 km N of Loíza, Puerto Rico
  2. 3.4 108 km NNE of San Juan, Puerto Rico
  3. 3.6 104 km N of San Juan, Puerto Rico
  4. 3.8 113 km N of San Juan, Puerto Rico
  5. 3.3 114 km NNE of Suárez, Puerto Rico
  6. 3.3 107 km N of San Juan, Puerto Rico
  7. 3.1 92 km NNE of San Juan, Puerto Rico
  8. 3.2 74 km N of San Juan, Puerto Rico
  9. 3.4 84 km NNE of Vieques, Puerto Rico
  10. 3.1 59 km N of Loíza, Puerto Rico
  11. 3.6 77 km N of San Juan, Puerto Rico
  12. 3.3 108 km N of San Juan, Puerto Rico
  13. 3.1 110 km N of San Juan, Puerto Rico
  14. 3.4 112 km NNE of Vieques, Puerto Rico
  15. 3.4 126 km NNE of Vieques, Puerto Rico

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.