QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

68 km SSW of Luquillo, Puerto Rico

Yes. A magnitude 2.8 earthquake was recorded 68 km SSW of Luquillo, Puerto Rico, 88 km (55 mi) NE of San Juan, PR, at 12:53 pm AST on 20 September 2018 (16:53 UTC), 66 km deep.

88 km (55 mi) NE of San Juan, PR

· 66 km deep · released about 530 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Fajardo Municipio 62 kmCulebra Municipio 67 kmLuquillo Municipio 68 kmRío Grande Municipio 72 kmLoíza Municipio 76 kmCeiba Municipio 77 kmCarolina Municipio 81 kmCanóvanas Municipio 82 kmNaguabo Municipio 85 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
66 km below the surface
Felt
no reports yet
Nearest
Fajardo Municipio, 62 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2906 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 530 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 29,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 20,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.8× the energy of this one
  4. This earthquake M 2.8 about 530 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 4.5 on 2018-03-06 — about 320 times the energy of this one.

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

  1. 5.1 92 km N of Suárez, Puerto Rico · 49 km NW of this epicentre
  2. 5.0 73 km NNE of Vieques, Puerto Rico · 12 km NW 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 18.9213, -65.4286. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Fajardo Municipio, PR 62 km (38 mi) SSW earthquakes near Fajardo Municipio
Culebra Municipio, PR 67 km (42 mi) S earthquakes near Culebra Municipio
Luquillo Municipio, PR 68 km (42 mi) SSW earthquakes near Luquillo Municipio
Río Grande Municipio, PR 72 km (45 mi) SSW earthquakes near Río Grande Municipio
Loíza Municipio, PR 76 km (47 mi) SW earthquakes near Loíza Municipio
Ceiba Municipio, PR 77 km (48 mi) SSW earthquakes near Ceiba Municipio

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

Aftershocks so far

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

  1. 2.6 83 km N of Charlotte Amalie, U.S. Virgin Islands
  2. 3.1 54 km NNE of Culebra, Puerto Rico
  3. 3.1 108 km NNW of Charlotte Amalie, U.S. Virgin Islands
  4. 2.2 74 km NNW of Charlotte Amalie, U.S. Virgin Islands
  5. 2.8 23 km NNE of Luquillo, Puerto Rico
  6. 2.5 28 km N of Culebra, Puerto Rico
  7. 2.9 28 km NNE of Luquillo, Puerto Rico
  8. 2.6 55 km NNW of Charlotte Amalie, U.S. Virgin Islands
  9. 3.2 69 km N of Charlotte Amalie, U.S. Virgin Islands
  10. 3.3 69 km N of Culebra, Puerto Rico
  11. 3.1 64 km N of Culebra, Puerto Rico
  12. 2.4 46 km NNE of Luquillo, Puerto Rico
  13. 3.2 36 km NNW of Charlotte Amalie, U.S. Virgin Islands
  14. 2.5 60 km NNW of Charlotte Amalie, U.S. Virgin Islands
  15. 3.0 62 km NNW 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.