QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Coamo, PR

No earthquake was likely felt in Coamo in the 24 hours to 1:01 pm AST (17:01 UTC). The last one was M 2.2, 6 km (4 mi) S, at 5:05 pm AST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Coamo

This page: a magnitude 1.6 earthquake was recorded 2 km (1 mi) west-southwest of Coamo, PR, at 9:27 pm AST on 20 May 2018 (01:27 UTC), 8.0 km deep.

USGS: 2 km WSW of Coamo, Puerto Rico

50 km (31 mi) SW of San Juan, PR · 28 km (17 mi) ENE of Ponce, PR

9:27 pm AST, May 20, 2018 · · 8.0 km deep · released about 8.7 lb of TNT

Every earthquake near Coamo Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Coamo Municipio 4 kmVillalba Municipio 12 kmSanta Isabel Municipio 13 kmAibonito Municipio 13 kmJuana Díaz Municipio 15 kmBarranquitas Municipio 16 kmSalinas Municipio 16 kmOrocovis Municipio 18 kmComerío Municipio 24 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
9:27 pm AST on 20 May 2018 ()
Where
2 km (1 mi) west-southwest of Coamo, PR · earthquakes near Coamo
Magnitude
M 1.6 (md)
Depth
8.0 km below the surface
Felt
no reports yet
Nearest
Coamo Municipio, 4 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3097 days ago

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

At this magnitude and depth, people at rest would likely notice it out to about 8 km (5 mi) from the epicentre. In Coamo, 2 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.

Likely felt in: Coamo 2 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 8.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,700,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,200,000× the energy of this one
  3. Around the size people start to feel M 3.0 110× the energy of this one
  4. This earthquake M 1.6 about 8.7 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 lists 2 earthquakes of M5 or more within 50 km:

  1. 5.1 3 km W of Aguas Buenas, Puerto Rico · 33 km NE of this epicentre
  2. 5.0 3 km N of Brenas, Puerto Rico · 48 km N 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 18.0708, -66.3745. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Coamo Municipio, PR 4 km (3 mi) NNE earthquakes near Coamo Municipio
Villalba Municipio, PR 12 km (8 mi) WNW earthquakes near Villalba Municipio
Santa Isabel Municipio, PR 13 km (8 mi) S earthquakes near Santa Isabel Municipio
Aibonito Municipio, PR 13 km (8 mi) ENE earthquakes near Aibonito Municipio
Juana Díaz Municipio, PR 15 km (9 mi) WSW earthquakes near Juana Díaz Municipio
Barranquitas Municipio, PR 16 km (10 mi) NNE earthquakes near Barranquitas Municipio

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

Aftershocks so far

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

  1. 2.5 4 km NNE of Guaynabo, Puerto Rico
  2. 1.5 0 km NNW of Buena Vista, Puerto Rico
  3. 2.4 14 km S of Tallaboa, Puerto Rico
  4. 1.9 5 km ENE of G. L. Garcia, Puerto Rico
  5. 1.6 1 km SW of Adjuntas, Puerto Rico
  6. 1.9 0 km SE of Adjuntas, Puerto Rico
  7. 1.9 1 km NE of Adjuntas, Puerto Rico
  8. 1.8 1 km SSW of Adjuntas, Puerto Rico
  9. 2.5 2 km S of Adjuntas, Puerto Rico
  10. 2.4 1 km SSW of Adjuntas, Puerto Rico
  11. 2.6 2 km SSW of Adjuntas, Puerto Rico
  12. 2.2 6 km SSW of Lamboglia, Puerto Rico
  13. 2.3 8 km NNE of Jayuya, Puerto Rico
  14. 1.9 11 km SSE of Jauca, Puerto Rico
  15. 2.1 1 km NE of Guayanilla, 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.