QuakeIndex

Earthquake · reviewed by a seismologist

M 4.4md

Puerto Rico region

Yes. A magnitude 4.4 earthquake was recorded in the Puerto Rico region, at 6:59 am AST on 28 February 2023 (10:59 UTC), 62 km deep. 4 people have reported feeling it to USGS.

· 62 km deep · released about 69 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 4.4 (md)
Depth
62 km below the surface
Felt
4 reports · strongest reported intensity II
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1284 days ago

This was a light earthquake. It is usually felt clearly nearby and can rattle windows and dishes, but damage is uncommon.

At this magnitude and depth, people at rest would likely notice it out to about 119 km (74 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 69 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 5.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 2,500× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 110× the energy of this one
  3. Magna, Utah 2020 M 5.7 78× the energy of this one
  4. This earthquake M 4.4 about 69 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 140× 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 4.9 on 2018-11-14 — about 4.9 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 19.5660, -65.3656. Map © OpenStreetMap contributors.

Aftershocks so far

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

  1. 3.4 Puerto Rico region
  2. 3.9 Puerto Rico region
  3. 3.9 Puerto Rico region
  4. 3.8 143 km N of Suárez, Puerto Rico
  5. 4.0 133 km N of Suárez, Puerto Rico
  6. 4.0 138 km N of Suárez, Puerto Rico
  7. 3.7 135 km N of Suárez, Puerto Rico
  8. 3.4 134 km N of Suárez, Puerto Rico
  9. 3.7 141 km NNE of Vieques, Puerto Rico
  10. 3.3 Puerto Rico region
  11. 3.7 Puerto Rico region
  12. 4.0 122 km N of Suárez, Puerto Rico
  13. 3.8 124 km N of Suárez, Puerto Rico
  14. 3.6 125 km N of Suárez, Puerto Rico
  15. 4.0 135 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.