QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9md

Earthquake near Ponce, PR

No earthquake was likely felt in Ponce in the 24 hours to 5:34 pm AST (21:34 UTC). The last one was M 3.0, 26 km (16 mi) WSW, at 3:45 am AST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Ponce

This page: a magnitude 2.9 earthquake was recorded 37 km (23 mi) southwest of Ponce, PR, at 3:17 am AST on 18 September 2021 (07:17 UTC), 5.0 km deep.

USGS: Puerto Rico region

36 km (22 mi) SW of Ponce, PR

3:17 am AST, Sep 18, 2021 · · 5.0 km deep · released about 610 lb of TNT

Every earthquake near Ponce Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Guánica Municipio 19 kmGuayanilla Municipio 26 kmLajas Municipio 28 kmPeñuelas Municipio 32 kmYauco Municipio 34 kmSabana Grande Municipio 35 kmPonce Municipio 38 kmSan Germán Municipio 40 kmCabo Rojo Municipio 40 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
3:17 am AST on 18 September 2021 ()
Where
37 km (23 mi) southwest of Ponce, PR · earthquakes near Ponce
Magnitude
M 2.9 (md)
Depth
5.0 km below the surface
Felt
no reports yet
Nearest
Guánica Municipio, 19 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1881 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, people at rest would likely notice it out to about 30 km (19 mi) from the epicentre. In Ponce, 37 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: Guayanilla 28 km, intensity II · Yauco 28 km, intensity II · Magas Arriba 29 km, intensity II · Tallaboa 29 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 610 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 25,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 18,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.6× the energy of this one
  4. This earthquake M 2.9 about 610 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 in our catalogue was M 6.4 on 2020-01-07 — about 200,000 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 17.7800, -66.8753. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Guánica Municipio, PR 19 km (12 mi) NNW earthquakes near Guánica Municipio
Guayanilla Municipio, PR 26 km (16 mi) NNE earthquakes near Guayanilla Municipio
Lajas Municipio, PR 28 km (17 mi) NW earthquakes near Lajas Municipio
Peñuelas Municipio, PR 32 km (20 mi) NNE earthquakes near Peñuelas Municipio
Yauco Municipio, PR 34 km (21 mi) N earthquakes near Yauco Municipio
Sabana Grande Municipio, PR 35 km (22 mi) NNW earthquakes near Sabana Grande Municipio

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

Aftershocks so far

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

  1. 2.0 12 km SSE of Guánica, Puerto Rico
  2. 1.7 2 km ENE of Magas Arriba, Puerto Rico
  3. 3.2 9 km NW of Coto Laurel, Puerto Rico
  4. 2.2 5 km SSW of Indios, Puerto Rico
  5. 3.2 5 km SSW of Indios, Puerto Rico
  6. 1.8 2 km NNE of Guayanilla, Puerto Rico
  7. 2.0 3 km NNW of Guayanilla, Puerto Rico
  8. 1.6 5 km WSW of La Parguera, Puerto Rico
  9. 1.9 9 km S of La Parguera, Puerto Rico
  10. 2.1 2 km SW of Indios, Puerto Rico
  11. 2.1 4 km W of Pole Ojea, Puerto Rico
  12. 2.8 7 km SE of Maria Antonia, Puerto Rico
  13. 2.4 1 km N of Magas Arriba, Puerto Rico
  14. 2.1 5 km SSE of Guánica, Puerto Rico
  15. 3.1 7 km ESE of Pole Ojea, 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.