QuakeIndex

Earthquake · reviewed by a seismologist

M 3.5md

Earthquake near Puerto Real, PR

No earthquake was likely felt in Puerto Real in the 24 hours to 8:51 pm AST (00:51 UTC). The last one was M 2.1, 10 km (6 mi) SE, at 11:57 pm AST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Puerto Real

This page: a magnitude 3.5 earthquake was recorded 22 km (14 mi) west-northwest of Puerto Real, PR, at 11:28 am AST on 30 October 2021 (15:28 UTC), 10 km deep. 1 person has reported feeling it to USGS.

USGS: 21 km WNW of Puerto Real, Puerto Rico

25 km (15 mi) W of Mayagüez, PR · 141 km (87 mi) W of San Juan, PR

11:28 am AST, Oct 30, 2021 · · 10 km deep · released about 3.1 tons of TNT

Every earthquake near Puerto Real Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Rincón Municipio 24 kmCabo Rojo Municipio 27 kmHormigueros Municipio 27 kmAñasco Municipio 29 kmAguada Municipio 31 kmSan Germán Municipio 36 kmMoca Municipio 39 kmLajas Municipio 41 kmLas Marías Municipio 42 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
11:28 am AST on 30 October 2021 ()
Where
22 km (14 mi) west-northwest of Puerto Real, PR · earthquakes near Puerto Real
Magnitude
M 3.5 (md)
Depth
10 km below the surface
Felt
1 report · strongest reported intensity IV
Measured shaking
intensity II (ShakeMap)
Nearest
Rincón Municipio, 24 km NNE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1762 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 65 km (40 mi) from the epicentre. In Puerto Real, 22 km away, the estimate is intensity III (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: Puerto Real 22 km, intensity III · Rincón 24 km, intensity III · Mayagüez 25 km, intensity III · Pole Ojea 29 km, intensity II · Aguada 31 km, intensity II · San Germán 36 km, intensity II · Aguadilla 38 km, intensity II · San Sebastián 45 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 3.1 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.5 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 55,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 2,500× the energy of this one
  3. Magna, Utah 2020 M 5.7 1,700× the energy of this one
  4. This earthquake M 3.5 about 3.1 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 6.5× more

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 5.3 on 2020-07-03 — about 440 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 · 35 km NNE of this epicentre
  2. 6.1 15 km WNW of San Antonio, Puerto Rico · 46 km NNE of this epicentre
  3. 5.8 4 km E of Moca, Puerto Rico · 42 km NE of this epicentre
  4. 5.2 19 km SW of Stella, Puerto Rico · 3 km N of this epicentre
  5. 5.1 21 km SW of Stella, Puerto Rico · 1 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 18.1603, -67.3723. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Rincón Municipio, PR 24 km (15 mi) NNE earthquakes near Rincón Municipio
Cabo Rojo Municipio, PR 27 km (17 mi) SE earthquakes near Cabo Rojo Municipio
Hormigueros Municipio, PR 27 km (17 mi) E earthquakes near Hormigueros Municipio
Añasco Municipio, PR 29 km (18 mi) ENE earthquakes near Añasco Municipio
Aguada Municipio, PR 31 km (19 mi) NE earthquakes near Aguada Municipio
San Germán Municipio, PR 36 km (22 mi) E earthquakes near San Germán Municipio

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

Aftershocks so far

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

  1. 2.5 6 km WSW of La Parguera, Puerto Rico
  2. 3.2 5 km SW of Stella, Puerto Rico
  3. 2.3 5 km W of Fuig, Puerto Rico
  4. 2.8 4 km ESE of La Parguera, Puerto Rico
  5. 1.6 9 km SE of La Parguera, Puerto Rico
  6. 3.1 44 km W of Puerto Real, Puerto Rico
  7. 2.0 7 km SE of La Parguera, Puerto Rico
  8. 1.5 6 km WSW of Fuig, Puerto Rico
  9. 3.6 59 km W of Rincón, Puerto Rico
  10. 2.7 5 km ENE of La Parguera, Puerto Rico
  11. 2.7 6 km WSW of Fuig, Puerto Rico
  12. 3.0 5 km WSW of La Parguera, Puerto Rico
  13. 3.2 6 km WSW of La Parguera, Puerto Rico
  14. 1.8 6 km WSW of La Parguera, Puerto Rico
  15. 2.5 4 km WSW of Fuig, 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.