QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

Earthquake near Arecibo, PR

No earthquake was likely felt in Arecibo in the 24 hours to 10:58 pm AST (02:58 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 2.4 earthquake was recorded 33 km (20 mi) north-northeast of Arecibo, PR, at 10:47 pm AST on 8 September 2018 (02:47 UTC), 44 km deep.

USGS: 31 km N of Garrochales, Puerto Rico

67 km (42 mi) NW of San Juan, PR · 35 km (22 mi) NNE of Arecibo, PR

10:47 pm AST, Sep 8, 2018 · · 44 km deep · released about 120 lb of TNT

Every earthquake near Arecibo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Barceloneta Municipio 30 kmManatí Municipio 34 kmArecibo Municipio 35 kmVega Baja Municipio 38 kmHatillo Municipio 40 kmFlorida Municipio 41 kmVega Alta Municipio 43 kmCamuy Municipio 44 kmDorado Municipio 46 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
10:47 pm AST on 8 September 2018 ()
Where
33 km (20 mi) north-northeast of Arecibo, PR · earthquakes near Arecibo
Magnitude
M 2.4 (md)
Depth
44 km below the surface
Felt
no reports yet
Nearest
Barceloneta Municipio, 30 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2986 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. In Arecibo, 33 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 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 130,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 92,000× the energy of this one
  3. Around the size people start to feel M 3.0 8.2× the energy of this one
  4. This earthquake M 2.4 about 120 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 4,100 times the energy of this one.

Before 2016, the USGS record lists 11 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.4 61 km N of Hatillo, Puerto Rico · 41 km NW of this epicentre
  2. 5.9 78 km N of Arecibo, Puerto Rico · 49 km N of this epicentre
  3. 5.8 12 km N of Garrochales, Puerto Rico · 20 km S of this epicentre
  4. 5.7 78 km N of Tierras Nuevas Poniente, Puerto Rico · 47 km N of this epicentre
  5. 5.6 57 km N of Isabela, Puerto Rico · 46 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 18.7403, -66.5918. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Barceloneta Municipio, PR 30 km (19 mi) S earthquakes near Barceloneta Municipio
Manatí Municipio, PR 34 km (21 mi) SSE earthquakes near Manatí Municipio
Arecibo Municipio, PR 35 km (22 mi) SSW earthquakes near Arecibo Municipio
Vega Baja Municipio, PR 38 km (23 mi) SSE earthquakes near Vega Baja Municipio
Hatillo Municipio, PR 40 km (25 mi) SSW earthquakes near Hatillo Municipio
Florida Municipio, PR 41 km (26 mi) S earthquakes near Florida Municipio

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

Aftershocks so far

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

  1. 3.2 66 km N of Arecibo, Puerto Rico
  2. 2.3 23 km NNE of Isabela, Puerto Rico
  3. 2.9 65 km NNE of Arecibo, Puerto Rico
  4. 2.5 55 km N of Tierras Nuevas Poniente, Puerto Rico
  5. 2.3 71 km N of Tierras Nuevas Poniente, Puerto Rico
  6. 2.8 61 km N of Tierras Nuevas Poniente, Puerto Rico
  7. 2.9 67 km N of Tierras Nuevas Poniente, Puerto Rico
  8. 2.4 70 km N of Tierras Nuevas Poniente, Puerto Rico
  9. 2.8 74 km N of Tierras Nuevas Poniente, Puerto Rico
  10. 2.5 57 km N of Hatillo, Puerto Rico
  11. 2.8 61 km NNE of Isabela, Puerto Rico
  12. 2.4 60 km N of Hatillo, Puerto Rico
  13. 2.3 9 km NNE of Carrizales, Puerto Rico
  14. 2.4 24 km N of Isabela, Puerto Rico
  15. 2.9 59 km NNE of Arecibo, 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.