QuakeIndex

Earthquake · reviewed by a seismologist

M 3.5md

Puerto Rico region

Yes. A magnitude 3.5 earthquake was recorded in the Puerto Rico region, at 11:38 pm AST on 28 February 2023 (03:38 UTC), 42 km deep.

· 42 km deep · released about 2.4 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Fajardo Municipio 78 kmCulebra Municipio 83 kmLuquillo Municipio 84 kmRío Grande Municipio 87 kmLoíza Municipio 89 kmCeiba Municipio 93 kmCarolina Municipio 95 kmCanóvanas Municipio 96 kmSan Juan Municipio 100 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 3.5 (md)
Depth
42 km below the surface
Felt
no reports yet
Nearest
Fajardo Municipio, 78 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1283 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 45 km (28 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 2.4 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 70,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 3,100× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,200× the energy of this one
  4. This earthquake M 3.5 about 2.4 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 5.1× 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 2021-03-09 — about 99 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 19.0670, -65.4031. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Fajardo Municipio, PR 78 km (49 mi) SSW earthquakes near Fajardo Municipio
Culebra Municipio, PR 83 km (52 mi) S earthquakes near Culebra Municipio
Luquillo Municipio, PR 84 km (52 mi) SSW earthquakes near Luquillo Municipio
Río Grande Municipio, PR 87 km (54 mi) SSW earthquakes near Río Grande Municipio
Loíza Municipio, PR 89 km (56 mi) SW earthquakes near Loíza Municipio
Ceiba Municipio, PR 93 km (58 mi) SSW earthquakes near Ceiba Municipio

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

Aftershocks so far

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

  1. 3.4 106 km NNE of Suárez, Puerto Rico
  2. 3.1 69 km N of Culebra, Puerto Rico
  3. 3.2 94 km N of Culebra, Puerto Rico
  4. 3.4 Virgin Islands
  5. 3.9 Puerto Rico region
  6. 3.3 62 km N of Charlotte Amalie, U.S. Virgin Islands
  7. 3.7 71 km NNE of Luquillo, Puerto Rico
  8. 3.9 113 km N of Suárez, Puerto Rico
  9. 3.9 Puerto Rico region
  10. 3.4 69 km NNE of Suárez, Puerto Rico
  11. 3.3 59 km NNE of Luquillo, Puerto Rico
  12. 3.1 Puerto Rico region
  13. 3.8 95 km NNW of Charlotte Amalie, U.S. Virgin Islands
  14. 3.8 72 km N of Charlotte Amalie, U.S. Virgin Islands
  15. 3.5 72 km N of Charlotte Amalie, U.S. Virgin Islands

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.