QuakeIndex

Earthquake · reviewed by a seismologist

M 4.0md

Puerto Rico region

Yes. A magnitude 4.0 earthquake was recorded in the Puerto Rico region, at 2:06 am AST on 20 May 2023 (06:06 UTC), 50 km deep.

· 50 km deep · released about 13 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N
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 4.0 (md)
Depth
50 km below the surface
Felt
no reports yet
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1272 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 80 km (50 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 13 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.0 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 13,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 580× the energy of this one
  3. Magna, Utah 2020 M 5.7 410× the energy of this one
  4. This earthquake M 4.0 about 13 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 28× 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 in our catalogue was M 4.4 on 2023-02-28 — about 5.2 times the energy of this one.

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 19.6275, -65.7343. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.7 136 km N of Suárez, Puerto Rico
  2. 3.9 130 km N of Suárez, Puerto Rico
  3. 2.5 123 km N of Suárez, Puerto Rico
  4. 3.8 124 km N of Su?rez, Puerto Rico
  5. 3.8 142 km N of Suárez, Puerto Rico
  6. 3.8 Puerto Rico region
  7. 4.0 132 km N of Suárez, Puerto Rico
  8. 3.9 135 km N of Suárez, Puerto Rico
  9. 3.5 90 km N of Suárez, Puerto Rico
  10. 3.7 129 km N of Suárez, Puerto Rico
  11. 3.8 122 km N of Suárez, Puerto Rico
  12. 3.5 122 km N of Suárez, Puerto Rico
  13. 3.9 110 km N of Suárez, Puerto Rico
  14. 3.8 149 km N of Suárez, Puerto Rico
  15. 3.7 135 km N of Suárez, 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.