QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Mayagüez, PR

No earthquake was likely felt in Mayagüez in the 24 hours to 1:20 am AST (05:20 UTC). The last one was M 2.9, 25 km (15 mi) SSE, at 3:17 am AST on 8 November 2026, estimated intensity II (weak) in town. Every earthquake near Mayagüez

This page: a magnitude 1.6 earthquake was recorded 6 km (3 mi) east of Mayagüez, PR, at 9:46 pm AST on 16 January 2021 (01:46 UTC), 9.0 km deep.

USGS: 5 km E of Mayagüez, Puerto Rico

6 km (4 mi) E of Mayagüez, PR · 110 km (69 mi) WSW of San Juan, PR

9:46 pm AST, Jan 16, 2021 · · 9.0 km deep · released about 8.4 lb of TNT

Every earthquake near Mayagüez Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Hormigueros Municipio 8 kmAñasco Municipio 11 kmSan Germán Municipio 12 kmLas Marías Municipio 12 kmMaricao Municipio 16 kmSan Sebastián Municipio 19 kmMoca Municipio 20 kmSabana Grande Municipio 20 kmAguada Municipio 22 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
9:46 pm AST on 16 January 2021 ()
Where
6 km (3 mi) east of Mayagüez, PR · earthquakes near Mayagüez
Magnitude
M 1.6 (md)
Depth
9.0 km below the surface
Felt
no reports yet
Nearest
Hormigueros Municipio, 8 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1980 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 7 km (4 mi) from the epicentre. In Mayagüez, 6 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: Mayagüez 6 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 8.4 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,300,000× the energy of this one
  3. Around the size people start to feel M 3.0 110× the energy of this one
  4. This earthquake M 1.6 about 8.4 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 14,000,000 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 · 30 km NNW of this epicentre
  2. 6.1 15 km WNW of San Antonio, Puerto Rico · 42 km NNW of this epicentre
  3. 6.1 18 km NNW of San Antonio, Puerto Rico · 49 km NNW of this epicentre
  4. 5.8 4 km E of Moca, Puerto Rico · 22 km N of this epicentre
  5. 5.2 19 km SW of Stella, Puerto Rico · 30 km W 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 18.2016, -67.0870. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Hormigueros Municipio, PR 8 km (5 mi) SSW earthquakes near Hormigueros Municipio
Añasco Municipio, PR 11 km (7 mi) NNW earthquakes near Añasco Municipio
San Germán Municipio, PR 12 km (7 mi) SSE earthquakes near San Germán Municipio
Las Marías Municipio, PR 12 km (7 mi) ENE earthquakes near Las Marías Municipio
Maricao Municipio, PR 16 km (10 mi) E earthquakes near Maricao Municipio
San Sebastián Municipio, PR 19 km (12 mi) NE earthquakes near San Sebastián Municipio

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

Aftershocks so far

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

  1. 1.6 7 km SE of Maria Antonia, Puerto Rico
  2. 3.0 4 km SW of Indios, Puerto Rico
  3. 2.0 8 km SSE of Maria Antonia, Puerto Rico
  4. 2.5 23 km W of Puerto Real, Puerto Rico
  5. 1.8 6 km S of Guánica, Puerto Rico
  6. 1.6 6 km ESE of Pole Ojea, Puerto Rico
  7. 2.2 7 km WSW of La Parguera, Puerto Rico
  8. 1.8 4 km SSW of Guánica, Puerto Rico
  9. 2.3 1 km S of Indios, Puerto Rico
  10. 2.0 2 km ESE of San Germán, Puerto Rico
  11. 1.6 0 km ESE of Sabana Eneas, Puerto Rico
  12. 1.9 6 km E of La Parguera, Puerto Rico
  13. 1.5 4 km WSW of Guánica, Puerto Rico
  14. 2.6 7 km S of Guánica, Puerto Rico
  15. 2.2 1 km SSE 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.