QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

Earthquake near Adjuntas, PR

No earthquake was likely felt in Adjuntas in the 24 hours to 12:52 pm AST (16:52 UTC). The last one was M 3.0, 31 km (19 mi) SSW, at 3:45 am AST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Adjuntas

This page: a magnitude 1.9 earthquake was recorded 5 km (3 mi) east-southeast of Adjuntas, PR, at 5:15 am AST on 3 September 2021 (09:15 UTC), 7.0 km deep.

USGS: 5 km ESE of Adjuntas, Puerto Rico

16 km (10 mi) NNW of Ponce, PR

5:15 am AST, Sep 3, 2021 · · 7.0 km deep · released about 19 lb of TNT

Every earthquake near Adjuntas Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Adjuntas Municipio 10 kmJayuya Municipio 13 kmPeñuelas Municipio 13 kmUtuado Municipio 15 kmPonce Municipio 17 kmGuayanilla Municipio 19 kmYauco Municipio 20 kmVillalba Municipio 22 kmCiales Municipio 25 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
5:15 am AST on 3 September 2021 ()
Where
5 km (3 mi) east-southeast of Adjuntas, PR · earthquakes near Adjuntas
Magnitude
M 1.9 (md)
Depth
7.0 km below the surface
Felt
no reports yet
Nearest
Adjuntas Municipio, 10 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1895 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 13 km (8 mi) from the epicentre. In Adjuntas, 5 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: Adjuntas 5 km, intensity II · Tallaboa Alta 10 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 19 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 5.8 790,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 560,000× the energy of this one
  3. Around the size people start to feel M 3.0 50× the energy of this one
  4. This earthquake M 1.9 about 19 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 6.4 on 2020-01-07 — about 6,200,000 times the energy of this one.

Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:

  1. 5.8 12 km N of Garrochales, Puerto Rico · 49 km NNE 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 18.1381, -66.6796. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Adjuntas Municipio, PR 10 km (6 mi) WNW earthquakes near Adjuntas Municipio
Jayuya Municipio, PR 13 km (8 mi) NE earthquakes near Jayuya Municipio
Peñuelas Municipio, PR 13 km (8 mi) SSW earthquakes near Peñuelas Municipio
Utuado Municipio, PR 15 km (9 mi) N earthquakes near Utuado Municipio
Ponce Municipio, PR 17 km (11 mi) SSE earthquakes near Ponce Municipio
Guayanilla Municipio, PR 19 km (12 mi) SW earthquakes near Guayanilla Municipio

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

Aftershocks so far

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

  1. 1.9 4 km SSW of Indios, Puerto Rico
  2. 2.3 2 km WSW of Indios, Puerto Rico
  3. 3.5 7 km WSW of Guánica, Puerto Rico
  4. 2.7 Puerto Rico region
  5. 3.2 4 km WSW of Fuig, Puerto Rico
  6. 3.3 12 km SSE of Ponce, Puerto Rico
  7. 2.4 6 km WSW of La Parguera, Puerto Rico
  8. 2.6 6 km WSW of La Parguera, Puerto Rico
  9. 2.3 5 km WSW of Guánica, Puerto Rico
  10. 2.8 3 km E of La Parguera, Puerto Rico
  11. 3.1 9 km S of Lares, Puerto Rico
  12. 2.2 6 km SE of Maria Antonia, Puerto Rico
  13. 2.8 1 km ENE of Magas Arriba, Puerto Rico
  14. 2.6 2 km NW of Guayanilla, Puerto Rico
  15. 1.9 3 km S 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.