QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9md

104 km N of Brenas, Puerto Rico

Yes. A magnitude 3.9 earthquake was recorded 104 km N of Brenas, Puerto Rico, at 8:24 pm AST on 9 January 2026 (00:24 UTC), 42 km deep. 1 person has reported feeling it to USGS.

· 42 km deep · released about 10 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Dorado Municipio 105 kmBarceloneta Municipio 106 kmVega Baja Municipio 106 kmManatí Municipio 108 kmToa Baja Municipio 108 kmVega Alta Municipio 108 kmCataño Municipio 111 kmArecibo Municipio 112 kmHatillo 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 3.9 (md)
Depth
42 km below the surface
Felt
1 report
Nearest
Dorado Municipio, 105 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 216 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 78 km (48 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 10 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 16,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 730× the energy of this one
  3. Magna, Utah 2020 M 5.7 520× the energy of this one
  4. This earthquake M 3.9 about 10 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 22× 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 2016-10-23 — about 5.8 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.9 78 km N of Arecibo, Puerto Rico · 36 km SW of this epicentre
  2. 5.7 78 km N of Tierras Nuevas Poniente, Puerto Rico · 31 km SSW of this epicentre
  3. 5.5 64 km N of Tierras Nuevas Poniente, Puerto Rico · 41 km S of this epicentre
  4. 5.4 106 km N of Brenas, Puerto Rico · 4 km NE of this epicentre
  5. 5.1 66 km N of Brenas, Puerto Rico · 38 km S 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 19.4083, -66.4083. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Dorado Municipio, PR 105 km (65 mi) S earthquakes near Dorado Municipio
Barceloneta Municipio, PR 106 km (66 mi) S earthquakes near Barceloneta Municipio
Vega Baja Municipio, PR 106 km (66 mi) S earthquakes near Vega Baja Municipio
Manatí Municipio, PR 108 km (67 mi) S earthquakes near Manatí Municipio
Toa Baja Municipio, PR 108 km (67 mi) SSE earthquakes near Toa Baja Municipio
Vega Alta Municipio, PR 108 km (67 mi) S earthquakes near Vega Alta 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 70 km N of Tierras Nuevas Poniente, Puerto Rico
  2. 3.0 71 km N of Tierras Nuevas Poniente, Puerto Rico
  3. 3.1 75 km N of Tierras Nuevas Poniente, Puerto Rico
  4. 3.0 72 km N of Tierras Nuevas Poniente, Puerto Rico
  5. 2.9 70 km N of Tierras Nuevas Poniente, Puerto Rico
  6. 3.1 72 km N of Tierras Nuevas Poniente, Puerto Rico
  7. 3.1 71 km N of Tierras Nuevas Poniente, Puerto Rico
  8. 3.1 75 km N of Tierras Nuevas Poniente, Puerto Rico
  9. 3.0 62 km N of Tierras Nuevas Poniente, Puerto Rico
  10. 3.6 95 km N of San Juan, Puerto Rico
  11. 3.6 121 km N of Hatillo, Puerto Rico
  12. 3.1 74 km N of Hatillo, Puerto Rico
  13. 3.6 104 km N of San Juan, Puerto Rico
  14. 3.8 113 km N of San Juan, Puerto Rico
  15. 3.2 75 km N of Brenas, 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.