QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

53 km W of Puerto Real, Puerto Rico

Yes. A magnitude 2.8 earthquake was recorded 53 km W of Puerto Real, Puerto Rico, 60 km (37 mi) WSW of Mayagüez, PR, at 5:15 am AST on 21 July 2018 (09:15 UTC), 125 km deep.

60 km (37 mi) WSW of Mayagüez, PR · 113 km (70 mi) W of Ponce, PR

· 125 km deep · released about 430 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Mayagüez Municipio 21 kmCabo Rojo Municipio 54 kmRincón Municipio 56 kmHormigueros Municipio 61 kmAguada Municipio 64 kmAñasco Municipio 64 kmSan Germán Municipio 69 kmLajas Municipio 69 kmMoca Municipio 73 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 2.8 (md)
Depth
125 km below the surface
Felt
no reports yet
Nearest
Mayagüez Municipio, 21 km W
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2960 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 430 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 35,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 25,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.2× the energy of this one
  4. This earthquake M 2.8 about 430 lb of TNT

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 2017-10-01 — about 280 times the energy of this one.

Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:

  1. 5.2 19 km SW of Stella, Puerto Rico · 37 km ENE of this epicentre
  2. 5.1 21 km SW of Stella, Puerto Rico · 36 km ENE 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 18.0585, -67.6888. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Mayagüez Municipio, PR 21 km (13 mi) W earthquakes near Mayagüez Municipio
Cabo Rojo Municipio, PR 54 km (34 mi) E earthquakes near Cabo Rojo Municipio
Rincón Municipio, PR 56 km (35 mi) NE earthquakes near Rincón Municipio
Hormigueros Municipio, PR 61 km (38 mi) E earthquakes near Hormigueros Municipio
Aguada Municipio, PR 64 km (40 mi) ENE earthquakes near Aguada Municipio
Añasco Municipio, PR 64 km (40 mi) ENE earthquakes near Añasco Municipio

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

Aftershocks so far

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

  1. 2.7 36 km WSW of Stella, Puerto Rico
  2. 2.8 72 km WSW of Stella, Puerto Rico
  3. 3.2 56 km SE of Punta Cana, Dominican Republic
  4. 2.6 21 km W of Rincón, Puerto Rico
  5. 2.9 63 km W of Rincón, Puerto Rico
  6. 2.4 24 km WSW of Stella, Puerto Rico
  7. 1.8 7 km W of Puerto Real, Puerto Rico
  8. 2.0 4 km WNW of Puerto Real, Puerto Rico
  9. 2.8 39 km W of Rincón, Puerto Rico
  10. 2.5 37 km WNW of Rincón, Puerto Rico
  11. 3.0 58 km ESE of Punta Cana, Dominican Republic
  12. 2.4 40 km WNW of Rincón, Puerto Rico
  13. 2.6 39 km WSW of Stella, Puerto Rico
  14. 2.3 53 km W of Rincón, Puerto Rico
  15. 2.9 56 km WSW of Stella, 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.