QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9md

Puerto Rico region

Yes. A magnitude 3.9 earthquake was recorded in the Puerto Rico region, 97 km (60 mi) NNW of San Juan, PR, at 11:29 pm AST on 31 December 2022 (03:29 UTC), 24 km deep.

97 km (60 mi) NNW of San Juan, PR

· 24 km deep · released about 12 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Barceloneta Municipio 77 kmVega Baja Municipio 80 kmManatí Municipio 80 kmDorado Municipio 81 kmArecibo Municipio 83 kmVega Alta Municipio 83 kmHatillo Municipio 85 kmToa Baja Municipio 86 kmCamuy Municipio 87 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
24 km below the surface
Felt
no reports yet
Nearest
Barceloneta Municipio, 77 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1341 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 88 km (55 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 12 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 14,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 640× the energy of this one
  3. Magna, Utah 2020 M 5.7 450× the energy of this one
  4. This earthquake M 3.9 about 12 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 25× 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 in our catalogue was M 4.8 on 2017-08-18 — about 20 times the energy of this one.

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 19.1631, -66.5251. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Barceloneta Municipio, PR 77 km (48 mi) S earthquakes near Barceloneta Municipio
Vega Baja Municipio, PR 80 km (50 mi) S earthquakes near Vega Baja Municipio
Manatí Municipio, PR 80 km (50 mi) S earthquakes near Manatí Municipio
Dorado Municipio, PR 81 km (51 mi) SSE earthquakes near Dorado Municipio
Arecibo Municipio, PR 83 km (51 mi) S earthquakes near Arecibo Municipio
Vega Alta Municipio, PR 83 km (52 mi) SSE earthquakes near Vega Alta Municipio

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

Aftershocks so far

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

  1. 3.9 118 km N of Brenas, Puerto Rico
  2. 3.3 65 km N of Hatillo, Puerto Rico
  3. 3.8 66 km N of Hatillo, Puerto Rico
  4. 2.9 30 km N of Arecibo, Puerto Rico
  5. 3.1 36 km N of Carrizales, Puerto Rico
  6. 3.4 52 km N of Hatillo, Puerto Rico
  7. 3.1 Puerto Rico region
  8. 3.1 54 km N of Hatillo, Puerto Rico
  9. 3.4 70 km NNE of Arecibo, Puerto Rico
  10. 3.2 78 km N of San Juan, Puerto Rico
  11. 3.3 Puerto Rico region
  12. 3.0 Puerto Rico region
  13. 2.9 87 km N of Brenas, Puerto Rico
  14. 3.4 63 km N of San Juan, Puerto Rico
  15. 3.4 109 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.