QuakeIndex

Earthquake · reviewed by a seismologist

M 3.1Md

96 km NNE of Vieques, Puerto Rico

Yes. A magnitude 3.1 earthquake was recorded 96 km NNE of Vieques, Puerto Rico, at 11:42 pm AST on 20 March 2017 (03:42 UTC), 34 km deep.

· 34 km deep · released about 1,300 lb of TNT

10 km30 km60 km120 km N Fajardo Municipio 91 kmCulebra Municipio 96 kmLuquillo Municipio 97 kmRío Grande Municipio 100 kmLoíza Municipio 100 kmCeiba Municipio 106 kmCarolina Municipio 106 kmCanóvanas Municipio 108 kmSan Juan Municipio 111 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 3.1 (Md)
Depth
34 km below the surface
Felt
no reports yet
Nearest
Fajardo Municipio, 91 km SSW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3522 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 24 km (15 mi) from the epicentre. 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.

How big was it?

This earthquake released about 1,300 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 250,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 11,000× the energy of this one
  3. Magna, Utah 2020 M 5.7 7,900× the energy of this one
  4. This earthquake M 3.1 about 1,300 lb of TNT
  5. Around the size people start to feel M 3.0 this one released 1.4× 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 4.3 on 2016-09-04 — about 63 times the energy of this one.

Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:

  1. 5.1 107 km N of Charlotte Amalie, U.S. Virgin Islands · 48 km ENE of this epicentre
  2. 5.1 122 km NNE of Vieques, Puerto Rico · 26 km NNE of this epicentre
  3. 5.1 92 km N of Suárez, Puerto Rico · 35 km WNW of this epicentre
  4. 5.0 109 km N of Charlotte Amalie, U.S. Virgin Islands · 43 km ENE of this epicentre
  5. 5.0 73 km NNE of Vieques, Puerto Rico · 23 km SSW 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 19.1868, -65.3977. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Fajardo Municipio, PR 91 km (57 mi) SSW earthquakes near Fajardo Municipio
Culebra Municipio, PR 96 km (60 mi) S earthquakes near Culebra Municipio
Luquillo Municipio, PR 97 km (60 mi) SSW earthquakes near Luquillo Municipio
Río Grande Municipio, PR 100 km (62 mi) SSW earthquakes near Río Grande Municipio
Loíza Municipio, PR 100 km (62 mi) SW earthquakes near Loíza Municipio
Ceiba Municipio, PR 106 km (66 mi) SSW earthquakes near Ceiba Municipio

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

Aftershocks so far

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

  1. 3.1 67 km NNE of Suárez, Puerto Rico
  2. 2.1 67 km N of Culebra, Puerto Rico
  3. 1.6 66 km N of Charlotte Amalie, U.S. Virgin Islands
  4. 2.3 102 km N of Culebra, Puerto Rico
  5. 2.3 96 km N of Culebra, Puerto Rico
  6. 3.3 112 km N of Suárez, Puerto Rico
  7. 3.1 102 km NNW of Charlotte Amalie, U.S. Virgin Islands
  8. 3.2 85 km N of Culebra, Puerto Rico
  9. 3.1 105 km N of Culebra, Puerto Rico
  10. 3.1 83 km NNW of Charlotte Amalie, U.S. Virgin Islands
  11. 2.8 64 km NNE of Luquillo, Puerto Rico
  12. 2.2 70 km N of Charlotte Amalie, U.S. Virgin Islands
  13. 2.4 71 km N of Charlotte Amalie, U.S. Virgin Islands
  14. 2.9 100 km NNW of Charlotte Amalie, U.S. Virgin Islands
  15. 3.1 90 km NNE of Vieques, 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.