QuakeIndex

Earthquake · reviewed by a seismologist

M 3.6md

75 km W of Puerto Real, Puerto Rico

Yes. A magnitude 3.6 earthquake was recorded 75 km W of Puerto Real, Puerto Rico, at 2:30 pm AST on 26 December 2020 (18:30 UTC), 107 km deep.

· 107 km deep · released about 3.8 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mayagüez Municipio 6 kmCabo Rojo Municipio 76 kmRincón Municipio 76 kmHormigueros Municipio 83 kmAguada Municipio 84 kmAñasco Municipio 85 kmLajas Municipio 91 kmSan Germán Municipio 91 kmAguadilla Municipio 94 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 3.6 (md)
Depth
107 km below the surface
Felt
no reports yet
Nearest
Mayagüez Municipio, 6 km N
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2076 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 it was probably too small to be felt, even directly above it. 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 3.8 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.6 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 45,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 2,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 1,400× the energy of this one
  4. This earthquake M 3.6 about 3.8 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 7.9× 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 2020-11-04 — about 16 times the energy of this one.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 18.0338, -67.8951. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mayagüez Municipio, PR 6 km (4 mi) N earthquakes near Mayagüez Municipio
Cabo Rojo Municipio, PR 76 km (47 mi) E earthquakes near Cabo Rojo Municipio
Rincón Municipio, PR 76 km (47 mi) ENE earthquakes near Rincón Municipio
Hormigueros Municipio, PR 83 km (52 mi) E earthquakes near Hormigueros Municipio
Aguada Municipio, PR 84 km (52 mi) ENE earthquakes near Aguada Municipio
Añasco Municipio, PR 85 km (53 mi) ENE earthquakes near Añasco Municipio

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

Aftershocks so far

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

  1. 3.0 79 km SE of Boca de Yuma, Dominican Republic
  2. 2.8 45 km SE of Boca de Yuma, Dominican Republic
  3. 3.7 38 km ESE of Boca de Yuma, Dominican Republic
  4. 3.5 67 km SE of Boca de Yuma, Dominican Republic
  5. 3.5 45 km SE of Boca de Yuma, Dominican Republic
  6. 3.7 49 km SSE of Punta Cana, Dominican Republic
  7. 3.2 59 km W of Stella, Puerto Rico
  8. 3.4 Dominican Republic region
  9. 3.2 38 km W of Rincón, Puerto Rico
  10. 2.8 31 km WSW of Stella, Puerto Rico
  11. 3.4 64 km SE of Boca de Yuma, Dominican Republic
  12. 3.5 52 km SE of Punta Cana, Dominican Republic
  13. 2.7 35 km W of Puerto Real, Puerto Rico
  14. 3.0 72 km SE of Boca de Yuma, Dominican Republic
  15. 3.4 55 km SE of Punta Cana, Dominican Republic

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.