QuakeIndex

Earthquake · reviewed by a seismologist

M 4.2mb

Earthquake near Magas Arriba, PR

Yes: an earthquake was likely felt in Magas Arriba in the last 24 hours. M 2.1, 9 km (5 mi) WSW of Magas Arriba, at 4:14 pm AST on 11 November 2026 (20:14 UTC); the estimated shaking in Magas Arriba was intensity II (weak). Every earthquake near Magas Arriba

This page: a magnitude 4.2 earthquake was recorded 3 km (2 mi) east of Magas Arriba, PR, at 1:18 am AST on 31 May 2021 (05:18 UTC), 15 km deep. 25 people have reported feeling it to USGS.

USGS: 2 km E of Magas Arriba, Puerto Rico

13 km (8 mi) W of Ponce, PR

1:18 am AST, May 31, 2021 · · 15 km deep · released about 30 tons of TNT

Every earthquake near Magas Arriba Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Peñuelas Municipio 2 kmGuayanilla Municipio 6 kmPonce Municipio 14 kmYauco Municipio 15 kmAdjuntas Municipio 19 kmGuánica Municipio 21 kmSabana Grande Municipio 23 kmJuana Díaz Municipio 27 kmMaricao Municipio 27 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
1:18 am AST on 31 May 2021 ()
Where
3 km (2 mi) east of Magas Arriba, PR · earthquakes near Magas Arriba
Magnitude
M 4.2 (mb)
Depth
15 km below the surface
Felt
25 reports · strongest reported intensity VI
Measured shaking
intensity IV (ShakeMap)
USGS impact alert
green
Nearest
Peñuelas Municipio, 2 km NE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1922 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 112 km (70 mi) from the epicentre. In Magas Arriba, 3 km away, the estimate is intensity IV (light). 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: Magas Arriba 3 km, intensity IV · Tallaboa 3 km, intensity IV · Guayanilla 5 km, intensity IV · Tallaboa Alta 6 km, intensity IV · Yauco 12 km, intensity III · Ponce 12 km, intensity III · Adjuntas 16 km, intensity III · Jayuya 28 km, intensity III. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 30 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.2 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 5,600× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 250× the energy of this one
  3. Magna, Utah 2020 M 5.7 180× the energy of this one
  4. This earthquake M 4.2 about 30 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 63× 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 6.4 on 2020-01-07 — about 2,000 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 18.0155, -66.7410. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Peñuelas Municipio, PR 2 km (1 mi) NE earthquakes near Peñuelas Municipio
Guayanilla Municipio, PR 6 km (4 mi) W earthquakes near Guayanilla Municipio
Ponce Municipio, PR 14 km (9 mi) E earthquakes near Ponce Municipio
Yauco Municipio, PR 15 km (9 mi) WNW earthquakes near Yauco Municipio
Adjuntas Municipio, PR 19 km (12 mi) N earthquakes near Adjuntas Municipio
Guánica Municipio, PR 21 km (13 mi) WSW earthquakes near Guánica Municipio

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

Aftershocks so far

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

  1. 2.8 5 km SSE of Guánica, Puerto Rico
  2. 3.2 5 km SE of La Parguera, Puerto Rico
  3. 2.4 1 km SW of Indios, Puerto Rico
  4. 3.0 7 km SE of Maria Antonia, Puerto Rico
  5. 2.2 3 km NNW of La Parguera, Puerto Rico
  6. 2.5 7 km SSE of Guánica, Puerto Rico
  7. 2.9 6 km ESE of Las Marías, Puerto Rico
  8. 2.7 2 km NNW of La Parguera, Puerto Rico
  9. 3.1 3 km NNW of La Parguera, Puerto Rico
  10. 2.5 10 km SSE of Guánica, Puerto Rico
  11. 3.1 3 km SW of Indios, Puerto Rico
  12. 2.8 2 km SE of Yauco, Puerto Rico
  13. 2.1 1 km SE of Palomas, Puerto Rico
  14. 3.0 9 km SSW of Tallaboa, Puerto Rico
  15. 2.9 5 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.