QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7md

Earthquake near Loíza, PR

No earthquake was likely felt in Loíza in the 24 hours to 8:39 pm AST (00:39 UTC). The last one was M 4.1, 78 km (48 mi) SE, at 5:44 am AST on 28 October 2026, estimated intensity II (weak) in town; 5 felt reports to USGS. Every earthquake near Loíza

This page: a magnitude 2.7 earthquake was recorded 27 km (17 mi) north of Loíza, PR, at 9:25 am AST on 18 March 2018 (13:25 UTC), 36 km deep.

USGS: 27 km N of Loíza, Puerto Rico

37 km (23 mi) NE of San Juan, PR · 32 km (20 mi) NNE of Carolina, PR

9:25 am AST, Mar 18, 2018 · · 36 km deep · released about 350 lb of TNT

Every earthquake near Loíza Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Loíza Municipio 27 kmCarolina Municipio 33 kmRío Grande Municipio 34 kmSan Juan Municipio 36 kmLuquillo Municipio 38 kmCanóvanas Municipio 39 kmCataño Municipio 40 kmTrujillo Alto Municipio 41 kmToa Baja Municipio 43 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
9:25 am AST on 18 March 2018 ()
Where
27 km (17 mi) north of Loíza, PR · earthquakes near Loíza
Magnitude
M 2.7 (md)
Depth
36 km below the surface
Felt
no reports yet
Nearest
Loíza Municipio, 27 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3160 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. In Loíza, 27 km away, the estimate is intensity II (weak). 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.

Earthquakes near other towns within 30 km: Suárez, Vieques.

How big was it?

This earthquake released about 350 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 43,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 31,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.7× the energy of this one
  4. This earthquake M 2.7 about 350 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

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 18.6758, -65.8621. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Loíza Municipio, PR 27 km (17 mi) SSW earthquakes near Loíza Municipio
Carolina Municipio, PR 33 km (21 mi) SSW earthquakes near Carolina Municipio
Río Grande Municipio, PR 34 km (21 mi) SSE earthquakes near Río Grande Municipio
San Juan Municipio, PR 36 km (22 mi) SW earthquakes near San Juan Municipio
Luquillo Municipio, PR 38 km (23 mi) SSE earthquakes near Luquillo Municipio
Canóvanas Municipio, PR 39 km (24 mi) S earthquakes near Canóvanas Municipio

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

Aftershocks so far

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

  1. 2.5 4 km NNE of Guaynabo, Puerto Rico
  2. 2.1 44 km NNE of Luquillo, Puerto Rico
  3. 2.3 2 km SSW of Bayamón, Puerto Rico
  4. 2.5 12 km NNE of Brenas, Puerto Rico
  5. 2.8 2 km NW of Dorado, Puerto Rico
  6. 2.5 0 km ENE of San Juan, Puerto Rico
  7. 2.2 5 km NNW of Levittown, Puerto Rico
  8. 1.9 9 km N of Levittown, Puerto Rico
  9. 2.4 39 km N of San Juan, Puerto Rico
  10. 3.1 1 km SSW of Santa Barbara, Puerto Rico
  11. 3.2 26 km NW of Culebra, Puerto Rico
  12. 2.4 44 km N of San Juan, Puerto Rico
  13. 2.5 27 km N of Brenas, Puerto Rico
  14. 2.7 22 km NNW of San Juan, Puerto Rico
  15. 2.8 15 km NNE of Suárez, 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.