QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7md

Earthquake near Hormigueros, PR

No earthquake was likely felt in Hormigueros in the 24 hours to 3:38 am AST (07:38 UTC). The last one was M 2.1, 15 km (9 mi) S, at 11:57 pm AST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Hormigueros

This page: a magnitude 1.7 earthquake was recorded 3 km (2 mi) north-northeast of Hormigueros, PR, at 12:33 pm AST on 18 December 2018 (16:33 UTC), 7.0 km deep.

USGS: 2 km NNE of Hormigueros, Puerto Rico

in Mayagüez, PR · 115 km (71 mi) WSW of San Juan, PR

12:33 pm AST, Dec 18, 2018 · · 7.0 km deep · released about 11 lb of TNT

Every earthquake near Hormigueros Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Hormigueros Municipio 3 kmSan Germán Municipio 11 kmAñasco Municipio 14 kmLas Marías Municipio 17 kmCabo Rojo Municipio 19 kmMaricao Municipio 20 kmSabana Grande Municipio 20 kmLajas Municipio 22 kmRincón 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
12:33 pm AST on 18 December 2018 ()
Where
3 km (2 mi) north-northeast of Hormigueros, PR · earthquakes near Hormigueros
Magnitude
M 1.7 (md)
Depth
7.0 km below the surface
Felt
no reports yet
Nearest
Hormigueros Municipio, 3 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2886 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 10 km (6 mi) from the epicentre. In Hormigueros, 3 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: Mayagüez 5 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,400,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 89× the energy of this one
  4. This earthquake M 1.7 about 11 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 4.3 on 2017-10-14 — about 7,900 times the energy of this one.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

  1. 6.3 6 km WNW of Aguadilla, Puerto Rico · 32 km NNW of this epicentre
  2. 6.1 15 km WNW of San Antonio, Puerto Rico · 45 km NNW of this epicentre
  3. 5.8 4 km E of Moca, Puerto Rico · 27 km NNE of this epicentre
  4. 5.2 19 km SW of Stella, Puerto Rico · 26 km W of this epicentre
  5. 5.1 21 km SW of Stella, Puerto Rico · 26 km W 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 18.1621, -67.1225. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Hormigueros Municipio, PR 3 km (2 mi) SSE earthquakes near Hormigueros Municipio
San Germán Municipio, PR 11 km (7 mi) SE earthquakes near San Germán Municipio
Añasco Municipio, PR 14 km (9 mi) N earthquakes near Añasco Municipio
Las Marías Municipio, PR 17 km (11 mi) ENE earthquakes near Las Marías Municipio
Cabo Rojo Municipio, PR 19 km (12 mi) SSW earthquakes near Cabo Rojo Municipio
Maricao Municipio, PR 20 km (12 mi) E earthquakes near Maricao Municipio

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

Aftershocks so far

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

  1. 1.9 3 km SW of Adjuntas, Puerto Rico
  2. 1.5 6 km NNE of Lluveras, Puerto Rico
  3. 2.6 7 km NNE of Lluveras, Puerto Rico
  4. 1.6 1 km E of Liborio Negron Torres, Puerto Rico
  5. 1.7 15 km SSE of Pole Ojea, Puerto Rico
  6. 1.8 13 km WNW of Puerto Real, Puerto Rico
  7. 1.8 8 km S of Tallaboa, Puerto Rico
  8. 1.8 11 km W of Adjuntas, Puerto Rico
  9. 1.6 3 km NNW of Isabela, Puerto Rico
  10. 1.8 5 km ESE of Maricao, Puerto Rico
  11. 1.6 1 km SE of Sabana Grande, Puerto Rico
  12. 1.9 17 km SSW of Guánica, Puerto Rico
  13. 2.2 7 km SW of La Parguera, Puerto Rico
  14. 1.9 5 km WSW of Puerto Real, Puerto Rico
  15. 1.7 13 km SSE of Indios, 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.