QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

50 km N of San Juan, Puerto Rico

Yes. A magnitude 2.8 earthquake was recorded 50 km N of San Juan, Puerto Rico, 57 km (35 mi) N of San Juan, PR, at 6:33 pm AST on 7 August 2018 (22:33 UTC), 41 km deep.

57 km (35 mi) N of San Juan, PR

· 41 km deep · released about 510 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Toa Baja Municipio 53 kmDorado Municipio 53 kmCataño Municipio 53 kmLoíza Municipio 54 kmSan Juan Municipio 55 kmCarolina Municipio 59 kmVega Alta Municipio 60 kmVega Baja Municipio 62 kmGuaynabo Municipio 64 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
41 km below the surface
Felt
no reports yet
Nearest
Toa Baja Municipio, 53 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3018 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 510 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 30,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 21,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.9× the energy of this one
  4. This earthquake M 2.8 about 510 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 4.8 on 2017-08-18 — about 930 times the energy of this one.

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

  1. 5.5 64 km N of Tierras Nuevas Poniente, Puerto Rico · 45 km WNW of this epicentre
  2. 5.1 66 km N of Brenas, Puerto Rico · 35 km WNW 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 18.9170, -66.0731. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Toa Baja Municipio, PR 53 km (33 mi) SSW earthquakes near Toa Baja Municipio
Dorado Municipio, PR 53 km (33 mi) SSW earthquakes near Dorado Municipio
Cataño Municipio, PR 53 km (33 mi) S earthquakes near Cataño Municipio
Loíza Municipio, PR 54 km (34 mi) SSE earthquakes near Loíza Municipio
San Juan Municipio, PR 55 km (34 mi) S earthquakes near San Juan Municipio
Carolina Municipio, PR 59 km (37 mi) S earthquakes near Carolina Municipio

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

Aftershocks so far

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

  1. 2.6 Puerto Rico region
  2. 2.9 61 km N of Tierras Nuevas Poniente, Puerto Rico
  3. 2.3 71 km N of Tierras Nuevas Poniente, Puerto Rico
  4. 2.8 61 km N of Tierras Nuevas Poniente, Puerto Rico
  5. 2.4 26 km N of San Juan, Puerto Rico
  6. 2.8 74 km N of Tierras Nuevas Poniente, Puerto Rico
  7. 3.0 75 km N of San Juan, Puerto Rico
  8. 2.8 40 km N of Dorado, Puerto Rico
  9. 2.4 8 km NNE of Dorado, Puerto Rico
  10. 3.2 74 km N of Brenas, Puerto Rico
  11. 2.8 48 km N of Brenas, Puerto Rico
  12. 2.3 77 km NNE of San Juan, Puerto Rico
  13. 2.6 72 km N of Suárez, Puerto Rico
  14. 3.1 93 km NNE of San Juan, Puerto Rico
  15. 2.5 33 km N of Tierras Nuevas Poniente, 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.