QuakeIndex

Earthquake · reviewed by a seismologist

M 3.7md

133 km NNE of Vieques, Puerto Rico

Yes. A magnitude 3.7 earthquake was recorded 133 km NNE of Vieques, Puerto Rico, at 4:38 am AST on 3 July 2019 (08:38 UTC), 34 km deep.

· 34 km deep · released about 5.7 tons of TNT

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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 3.7 (md)
Depth
34 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2603 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 69 km (43 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 5.7 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.7 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 30,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 1,300× the energy of this one
  3. Magna, Utah 2020 M 5.7 930× the energy of this one
  4. This earthquake M 3.7 about 5.7 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 12× 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 4.9 on 2018-11-14 — about 59 times the energy of this one.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.1 122 km NNE of Vieques, Puerto Rico · 20 km SSE of this epicentre
  2. 5.1 92 km N of Suárez, Puerto Rico · 47 km SW of this epicentre
  3. 5.0 109 km N of Charlotte Amalie, U.S. Virgin Islands · 49 km ESE 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 19.5653, -65.4086. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.3 121 km N of Suárez, Puerto Rico
  2. 2.9 104 km NNE of Vieques, Puerto Rico
  3. 2.9 99 km NNE of Vieques, Puerto Rico
  4. 3.3 Puerto Rico region
  5. 2.6 95 km N of Suárez, Puerto Rico
  6. 2.7 118 km NNE of San Juan, Puerto Rico
  7. 3.0 151 km NNE of Vieques, Puerto Rico
  8. 2.7 Puerto Rico region
  9. 3.0 120 km NNE of Vieques, Puerto Rico
  10. 2.6 123 km N of Charlotte Amalie, U.S. Virgin Islands
  11. 3.3 135 km N of Charlotte Amalie, U.S. Virgin Islands
  12. 3.4 Puerto Rico region
  13. 3.2 130 km NNE of Vieques, Puerto Rico
  14. 2.8 84 km NNE of Vieques, Puerto Rico
  15. 3.0 119 km N of Charlotte Amalie, U.S. Virgin Islands

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.