QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

Earthquake near Monte Grande, PR

No earthquake was likely felt in Monte Grande in the 24 hours to 12:54 pm AST (16:54 UTC). The last one was M 2.1, 9 km (6 mi) S, at 11:57 pm AST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Monte Grande

This page: a magnitude 1.9 earthquake was recorded 2 km (1 mi) north-northeast of Monte Grande, PR, at 8:06 pm AST on 29 June 2018 (00:06 UTC), 18 km deep.

USGS: 2 km NNE of Monte Grande, Puerto Rico

12 km (7 mi) SSE of Mayagüez, PR · 114 km (71 mi) WSW of San Juan, PR

8:06 pm AST, Jun 29, 2018 · · 18 km deep · released about 22 lb of TNT

Every earthquake near Monte Grande Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Hormigueros Municipio 4 kmSan Germán Municipio 7 kmCabo Rojo Municipio 15 kmLajas Municipio 15 kmSabana Grande Municipio 16 kmLas Marías Municipio 19 kmMaricao Municipio 19 kmAñasco Municipio 21 kmGuánica Municipio 26 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
8:06 pm AST on 29 June 2018 ()
Where
2 km (1 mi) north-northeast of Monte Grande, PR · earthquakes near Monte Grande
Magnitude
M 1.9 (md)
Depth
18 km below the surface
Felt
no reports yet
Nearest
Hormigueros Municipio, 4 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3056 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 Monte Grande, 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.

Earthquakes near other towns within 30 km: Sabana Eneas, Hormigueros, Cabo Rojo, San Germán, Lajas, Palmarejo.

How big was it?

This earthquake released about 22 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 680,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 480,000× the energy of this one
  3. Around the size people start to feel M 3.0 43× the energy of this one
  4. This earthquake M 1.9 about 22 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 4 earthquakes of M5 or more within 50 km:

  1. 6.3 6 km WNW of Aguadilla, Puerto Rico · 39 km NNW of this epicentre
  2. 5.8 4 km E of Moca, Puerto Rico · 33 km N of this epicentre
  3. 5.2 19 km SW of Stella, Puerto Rico · 30 km WNW of this epicentre
  4. 5.1 21 km SW of Stella, Puerto Rico · 30 km WNW 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 18.1045, -67.0995. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Hormigueros Municipio, PR 4 km (2 mi) NNW earthquakes near Hormigueros Municipio
San Germán Municipio, PR 7 km (4 mi) E earthquakes near San Germán Municipio
Cabo Rojo Municipio, PR 15 km (9 mi) SW earthquakes near Cabo Rojo Municipio
Lajas Municipio, PR 15 km (10 mi) SSE earthquakes near Lajas Municipio
Sabana Grande Municipio, PR 16 km (10 mi) E earthquakes near Sabana Grande Municipio
Las Marías Municipio, PR 19 km (12 mi) NE earthquakes near Las Marías 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. 1.6 8 km ENE of Sabana Grande, Puerto Rico
  2. 1.6 13 km S of La Parguera, Puerto Rico
  3. 1.6 10 km SSE of La Parguera, Puerto Rico
  4. 2.5 19 km W of Rincón, Puerto Rico
  5. 1.6 18 km SSW of Guánica, Puerto Rico
  6. 2.0 4 km SSW of Añasco, Puerto Rico
  7. 1.9 2 km WNW of Guayanilla, Puerto Rico
  8. 2.0 3 km N of Puerto Real, Puerto Rico
  9. 1.9 12 km W of Pole Ojea, Puerto Rico
  10. 1.9 6 km W of Las Marías, Puerto Rico
  11. 2.4 Puerto Rico region
  12. 1.8 4 km NE of La Parguera, Puerto Rico
  13. 2.7 18 km SSE of Guánica, Puerto Rico
  14. 2.2 25 km S of Guánica, Puerto Rico
  15. 2.1 Puerto Rico region

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.