QuakeIndex

Earthquake · reviewed by a seismologist

M 3.9md

68 km N of San Juan, Puerto Rico

· 6.0 km deep · released about 9.6 tons of TNT

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10 km30 km60 km120 km N Dorado Municipio 70 kmToa Baja Municipio 70 kmCataño Municipio 71 kmLoíza Municipio 73 kmSan Juan Municipio 73 kmVega Alta Municipio 76 kmVega Baja Municipio 76 kmCarolina Municipio 77 kmToa Alta Municipio 81 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
6.0 km below the surface
Felt
25 reports · strongest reported intensity III
Nearest
Dorado Municipio, 70 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1860 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage. 25 people have reported feeling it to USGS.

How big was it?

This earthquake released about 9.6 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 18,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 790× the energy of this one
  3. Magna, Utah 2020 M 5.7 560× the energy of this one
  4. This earthquake M 3.9 about 9.6 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 20× 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 19.0816, -66.1018. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Dorado Municipio, PR 70 km (43 mi) NNE of here earthquakes near Dorado Municipio
Toa Baja Municipio, PR 70 km (44 mi) N of here earthquakes near Toa Baja Municipio
Cataño Municipio, PR 71 km (44 mi) N of here earthquakes near Cataño Municipio
Loíza Municipio, PR 73 km (45 mi) NNW of here earthquakes near Loíza Municipio
San Juan Municipio, PR 73 km (46 mi) N of here earthquakes near San Juan Municipio
Vega Alta Municipio, PR 76 km (47 mi) NNE of here earthquakes near Vega Alta Municipio

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

Aftershocks so far

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

  1. 3.1 61 km N of Brenas, Puerto Rico
  2. 3.2 60 km N of Loíza, Puerto Rico
  3. 2.7 71 km NNE of San Juan, Puerto Rico
  4. 3.0 42 km N of Tierras Nuevas Poniente, Puerto Rico
  5. 3.9 78 km N of San Juan, Puerto Rico
  6. 3.5 69 km N of Brenas, Puerto Rico
  7. 3.3 68 km N of Brenas, Puerto Rico
  8. 3.5 69 km N of Brenas, Puerto Rico
  9. 3.5 66 km N of Brenas, Puerto Rico
  10. 3.6 94 km N of Brenas, Puerto Rico
  11. 3.4 75 km N of Tierras Nuevas Poniente, Puerto Rico
  12. 2.3 59 km N of Tierras Nuevas Poniente, Puerto Rico
  13. 3.0 67 km N of Tierras Nuevas Poniente, Puerto Rico
  14. 3.2 Puerto Rico region
  15. 3.7 107 km N of Brenas, 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 4.8 on 2017-08-18 — it released about 25 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.