QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1md

Mona Passage

Yes. A magnitude 3.1 earthquake was recorded in Mona Passage, 47 km (29 mi) NW of Arecibo, PR, at 11:45 pm AST on 7 May 2018 (03:45 UTC), 71 km deep.

47 km (29 mi) NW of Arecibo, PR · 109 km (68 mi) WNW of San Juan, PR

· 71 km deep · released about 1,600 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Isabela Municipio 33 kmAguadilla Municipio 35 kmQuebradillas Municipio 36 kmCamuy Municipio 41 kmHatillo Municipio 44 kmMoca Municipio 45 kmAguada Municipio 48 kmSan Sebastián Municipio 50 kmArecibo Municipio 53 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 3.1 (md)
Depth
71 km below the surface
Felt
no reports yet
Nearest
Isabela Municipio, 33 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3017 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 1,600 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 210,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 9,400× the energy of this one
  3. Magna, Utah 2020 M 5.7 6,700× the energy of this one
  4. This earthquake M 3.1 about 1,600 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.7× more

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 in our catalogue was M 4.7 on 2017-07-17 — about 180 times the energy of this one.

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 18.7768, -67.0245. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Isabela Municipio, PR 33 km (20 mi) S earthquakes near Isabela Municipio
Aguadilla Municipio, PR 35 km (22 mi) SSW earthquakes near Aguadilla Municipio
Quebradillas Municipio, PR 36 km (22 mi) SSE earthquakes near Quebradillas Municipio
Camuy Municipio, PR 41 km (25 mi) SSE earthquakes near Camuy Municipio
Hatillo Municipio, PR 44 km (28 mi) SSE earthquakes near Hatillo Municipio
Moca Municipio, PR 45 km (28 mi) S earthquakes near Moca Municipio

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

Aftershocks so far

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

  1. 2.1 12 km NNW of Camuy, Puerto Rico
  2. 3.1 37 km NNW of San Antonio, Puerto Rico
  3. 2.6 59 km NNE of Isabela, Puerto Rico
  4. 2.6 39 km NW of San Antonio, Puerto Rico
  5. 2.8 8 km NNE of San Antonio, Puerto Rico
  6. 2.7 42 km NW of San Antonio, Puerto Rico
  7. 2.9 9 km NW of Caban, Puerto Rico
  8. 2.6 Puerto Rico region
  9. 2.8 Mona Passage
  10. 2.6 Mona Passage
  11. 3.0 63 km NNW of San Antonio, Puerto Rico
  12. 2.6 29 km N of Hatillo, Puerto Rico
  13. 2.0 Mona Passage
  14. 2.9 58 km NNW of San Antonio, Puerto Rico
  15. 2.5 4 km NNW 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.