QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9md

20 km S of Guánica, Puerto Rico

· 4.0 km deep · released about 10 tons of TNT

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10 km30 km60 km120 km N Guánica Municipio 19 kmGuayanilla Municipio 26 kmLajas Municipio 28 kmPeñuelas Municipio 31 kmYauco Municipio 33 kmSabana Grande Municipio 34 kmPonce Municipio 37 kmSan Germán Municipio 40 kmCabo Rojo Municipio 40 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
Magnitude
M 3.9 (md)
Depth
4.0 km below the surface
Felt
3 reports · strongest reported intensity III
Measured shaking
intensity III (ShakeMap)
Nearest
Guánica Municipio, 19 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2346 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 3 people have reported feeling it to USGS.

How big was it?

This earthquake released about 10 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.9 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 16,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 730× the energy of this one
  3. Magna, Utah 2020 M 5.7 520× the energy of this one
  4. This earthquake M 3.9 about 10 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 22× 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.

Where

Epicentre 17.7870, -66.8741. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Guánica Municipio, PR 19 km (12 mi) SSE of here earthquakes near Guánica Municipio
Guayanilla Municipio, PR 26 km (16 mi) SSW of here earthquakes near Guayanilla Municipio
Lajas Municipio, PR 28 km (17 mi) SE of here earthquakes near Lajas Municipio
Peñuelas Municipio, PR 31 km (19 mi) SSW of here earthquakes near Peñuelas Municipio
Yauco Municipio, PR 33 km (21 mi) S of here earthquakes near Yauco Municipio
Sabana Grande Municipio, PR 34 km (21 mi) SSE of here earthquakes near Sabana Grande 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. 2.7 20 km S of Guánica, Puerto Rico
  2. 2.4 7 km S of Tallaboa, Puerto Rico
  3. 2.6 11 km SSE of Tallaboa, Puerto Rico
  4. 2.5 10 km SSE of Tallaboa, Puerto Rico
  5. 2.6 11 km SSE of Guánica, Puerto Rico
  6. 3.2 19 km S of Guánica, Puerto Rico
  7. 2.4 8 km SSE of Tallaboa, Puerto Rico
  8. 2.8 Puerto Rico region
  9. 3.4 1 km ESE of Maria Antonia, Puerto Rico
  10. 3.4 14 km SSE of Guánica, Puerto Rico
  11. 2.6 5 km S of Guánica, Puerto Rico
  12. 3.1 10 km SSE of Maria Antonia, Puerto Rico
  13. 3.2 8 km SSE of Maria Antonia, Puerto Rico
  14. 2.9 24 km S of Guánica, Puerto Rico
  15. 2.6 28 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.

For this area

The largest earthquake within 50 km in our catalogue was M 6.4 on 2020-01-07 — it released about 5,800 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.