QuakeIndex

Earthquake · reviewed by a seismologist

M 3.0md

Earthquake near Las Marias, PR

No earthquake was likely felt in Las Marias in the 24 hours to 5:26 pm AST (21:26 UTC). The last one was M 3.5, 12 km (8 mi) NNE, at 12:03 am AST on 6 November 2026, estimated intensity II (weak) in town. Every earthquake near Las Marias

This page: a magnitude 3.0 earthquake was recorded 10 km (6 mi) east-southeast of Las Marias, PR, at 7:57 am AST on 21 April 2020 (11:57 UTC), 17 km deep. 2 people have reported feeling it to USGS.

USGS: 6 km WNW of Las Marías, Puerto Rico

12 km (7 mi) NE of Mayagüez, PR · 106 km (66 mi) W of San Juan, PR

7:57 am AST, Apr 21, 2020 · · 17 km deep · released about 890 lb of TNT

Every earthquake near Las Marias Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Añasco Municipio 9 kmLas Marías Municipio 9 kmSan Sebastián Municipio 11 kmMoca Municipio 13 kmHormigueros Municipio 16 kmMaricao Municipio 16 kmSan Germán Municipio 18 kmAguada Municipio 18 kmLares Municipio 19 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
7:57 am AST on 21 April 2020 ()
Where
10 km (6 mi) east-southeast of Las Marias, PR · earthquakes near Las Marias
Magnitude
M 3.0 (md)
Depth
17 km below the surface
Felt
2 reports · strongest reported intensity II
Nearest
Añasco Municipio, 9 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2395 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 31 km (19 mi) from the epicentre. In Las Marias, 10 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: San Sebastián 10 km, intensity II · Mayagüez 12 km, intensity II · Lares 19 km, intensity II · Aguada 19 km, intensity II · San Germán 21 km, intensity II · Aguadilla 21 km, intensity II · Rincón 22 km, intensity II · Rafael Hernandez 23 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 890 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 380,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 17,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 12,000× the energy of this one
  4. This earthquake M 3.0 about 890 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 130,000 times the energy of this one.

Before 2016, the USGS record lists 6 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.3 6 km WNW of Aguadilla, Puerto Rico · 26 km NW of this epicentre
  2. 6.1 15 km WNW of San Antonio, Puerto Rico · 37 km NNW of this epicentre
  3. 6.1 18 km NNW of San Antonio, Puerto Rico · 43 km NNW of this epicentre
  4. 5.8 4 km E of Moca, Puerto Rico · 15 km N of this epicentre
  5. 5.2 19 km SW of Stella, Puerto Rico · 35 km WSW 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 18.2670, -67.0535. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Añasco Municipio, PR 9 km (5 mi) WNW earthquakes near Añasco Municipio
Las Marías Municipio, PR 9 km (6 mi) ESE earthquakes near Las Marías Municipio
San Sebastián Municipio, PR 11 km (7 mi) NE earthquakes near San Sebastián Municipio
Moca Municipio, PR 13 km (8 mi) NNW earthquakes near Moca Municipio
Hormigueros Municipio, PR 16 km (10 mi) SSW earthquakes near Hormigueros Municipio
Maricao Municipio, PR 16 km (10 mi) SE earthquakes near Maricao Municipio

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

Aftershocks so far

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

  1. 2.9 6 km SSE of Guánica, Puerto Rico
  2. 2.8 0 km W of Guánica, Puerto Rico
  3. 2.4 5 km ESE of Maria Antonia, Puerto Rico
  4. 2.5 12 km SSE of Guánica, Puerto Rico
  5. 2.5 2 km SE of Guánica, Puerto Rico
  6. 2.4 4 km SSW of Guánica, Puerto Rico
  7. 2.4 11 km SSE of Maria Antonia, Puerto Rico
  8. 2.3 8 km SSE of Maria Antonia, Puerto Rico
  9. 2.5 11 km SSE of Maria Antonia, Puerto Rico
  10. 2.8 1 km WSW of Indios, Puerto Rico
  11. 2.6 9 km SSE of Maria Antonia, Puerto Rico
  12. 2.8 6 km WSW of Fuig, Puerto Rico
  13. 2.6 3 km SSW of Indios, Puerto Rico
  14. 2.5 4 km SW of Fuig, Puerto Rico
  15. 2.8 10 km S of Guánica, 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.