QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Adjuntas, PR

No earthquake was likely felt in Adjuntas in the 24 hours to 7:57 pm AST (23:57 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 1.6 earthquake was recorded 7 km (4 mi) south-southeast of Adjuntas, PR, at 4:24 am AST on 10 January 2021 (08:24 UTC), 11 km deep.

USGS: 6 km SSE of Adjuntas, Puerto Rico

14 km (9 mi) NNW of Ponce, PR

4:24 am AST, Jan 10, 2021 · · 11 km deep · released about 8.4 lb of TNT

Every earthquake near Adjuntas Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Peñuelas Municipio 10 kmAdjuntas Municipio 11 kmPonce Municipio 15 kmJayuya Municipio 15 kmGuayanilla Municipio 17 kmUtuado Municipio 18 kmYauco Municipio 18 kmVillalba Municipio 23 kmJuana Díaz 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
4:24 am AST on 10 January 2021 ()
Where
7 km (4 mi) south-southeast of Adjuntas, PR · earthquakes near Adjuntas
Magnitude
M 1.6 (md)
Depth
11 km below the surface
Felt
no reports yet
Nearest
Peñuelas Municipio, 10 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2042 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 4 km (2 mi) from the epicentre. In Adjuntas, 7 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.

Earthquakes near other towns within 30 km: Tallaboa Alta, Peñuelas, Santo Domingo, Ponce, Tallaboa, Magas Arriba.

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 since 1900 lists no earthquake of M5 or more within 50 km.

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 18.1118, -66.6895. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Peñuelas Municipio, PR 10 km (6 mi) SSW earthquakes near Peñuelas Municipio
Adjuntas Municipio, PR 11 km (7 mi) NW earthquakes near Adjuntas Municipio
Ponce Municipio, PR 15 km (9 mi) SE earthquakes near Ponce Municipio
Jayuya Municipio, PR 15 km (10 mi) NE earthquakes near Jayuya Municipio
Guayanilla Municipio, PR 17 km (10 mi) SW earthquakes near Guayanilla Municipio
Utuado Municipio, PR 18 km (11 mi) N earthquakes near Utuado 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. 1.5 6 km WSW of Guánica, Puerto Rico
  2. 2.1 3 km NW of Hormigueros, Puerto Rico
  3. 2.2 2 km S of Indios, Puerto Rico
  4. 2.0 5 km SSW of Indios, Puerto Rico
  5. 1.9 4 km SSW of Indios, Puerto Rico
  6. 2.4 5 km ESE of La Parguera, Puerto Rico
  7. 1.5 3 km WSW of La Parguera, Puerto Rico
  8. 2.3 5 km WSW of Fuig, Puerto Rico
  9. 1.5 2 km SE of Maria Antonia, Puerto Rico
  10. 2.3 4 km SSE of Guánica, Puerto Rico
  11. 1.6 4 km ESE of Maria Antonia, Puerto Rico
  12. 1.9 3 km ESE of Palomas, Puerto Rico
  13. 2.2 6 km SE of Maria Antonia, Puerto Rico
  14. 1.6 0 km SSE of Parcelas Peñuelas, Puerto Rico
  15. 1.7 2 km SE of Palmarejo, 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.