QuakeIndex

Earthquake · reviewed by a seismologist

M 2.8md

Earthquake near Arecibo, PR

No earthquake was likely felt in Arecibo in the 24 hours to 1:02 pm AST (17:02 UTC). The last one was M 3.4, 49 km (31 mi) NW, at 9:00 pm AST on 27 October 2026, estimated intensity II (weak) in town. Every earthquake near Arecibo

This page: a magnitude 2.8 earthquake was recorded 43 km (27 mi) north of Arecibo, PR, at 10:51 pm AST on 6 April 2018 (02:51 UTC), 47 km deep.

USGS: 41 km N of Carrizales, Puerto Rico

88 km (55 mi) NW of San Juan, PR · 45 km (28 mi) N of Arecibo, PR

10:51 pm AST, Apr 6, 2018 · · 47 km deep · released about 460 lb of TNT

Every earthquake near Arecibo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Hatillo Municipio 47 kmBarceloneta Municipio 47 kmCamuy Municipio 47 kmQuebradillas Municipio 48 kmArecibo Municipio 48 kmIsabela Municipio 50 kmManatí Municipio 53 kmFlorida Municipio 58 kmVega Baja Municipio 58 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
10:51 pm AST on 6 April 2018 ()
Where
43 km (27 mi) north of Arecibo, PR · earthquakes near Arecibo
Magnitude
M 2.8 (md)
Depth
47 km below the surface
Felt
no reports yet
Nearest
Hatillo Municipio, 47 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3140 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 Arecibo, 43 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.

How big was it?

This earthquake released about 460 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 33,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 23,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.1× the energy of this one
  4. This earthquake M 2.8 about 460 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 1,000 times the energy of this one.

Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.7 45 km N of San Antonio, Puerto Rico · 40 km W of this epicentre
  2. 7.1 24 km NNW of San Antonio, Puerto Rico · 50 km WSW of this epicentre
  3. 6.4 61 km N of Hatillo, Puerto Rico · 22 km NNW of this epicentre
  4. 6.0 81 km N of Isabela, Puerto Rico · 45 km NNW of this epicentre
  5. 5.9 78 km N of Arecibo, Puerto Rico · 37 km NNE 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 18.8573, -66.7455. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Hatillo Municipio, PR 47 km (29 mi) S earthquakes near Hatillo Municipio
Barceloneta Municipio, PR 47 km (29 mi) SSE earthquakes near Barceloneta Municipio
Camuy Municipio, PR 47 km (29 mi) SSW earthquakes near Camuy Municipio
Quebradillas Municipio, PR 48 km (30 mi) SSW earthquakes near Quebradillas Municipio
Arecibo Municipio, PR 48 km (30 mi) S earthquakes near Arecibo Municipio
Isabela Municipio, PR 50 km (31 mi) SW earthquakes near Isabela Municipio

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

Aftershocks so far

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

  1. 2.8 67 km N of Brenas, Puerto Rico
  2. 2.7 50 km N of Tierras Nuevas Poniente, Puerto Rico
  3. 2.1 56 km N of Tierras Nuevas Poniente, Puerto Rico
  4. 2.4 14 km NNW of Isabela, Puerto Rico
  5. 2.4 12 km N of Arecibo, Puerto Rico
  6. 2.2 19 km N of Arecibo, Puerto Rico
  7. 2.2 72 km N of Brenas, Puerto Rico
  8. 2.8 61 km N of Isabela, Puerto Rico
  9. 2.8 61 km N of Hatillo, Puerto Rico
  10. 2.6 27 km N of Arecibo, Puerto Rico
  11. 1.6 36 km N of San Antonio, Puerto Rico
  12. 2.8 Puerto Rico region
  13. 2.9 52 km N of Hatillo, Puerto Rico
  14. 2.8 Puerto Rico region
  15. 2.8 62 km N of Hatillo, 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.