QuakeIndex

Earthquake · reviewed by a seismologist

M 2.4md

121 km N of San Juan, Puerto Rico

Yes. A magnitude 2.4 earthquake was recorded 121 km N of San Juan, Puerto Rico, at 4:22 am AST on 19 December 2019 (08:22 UTC), 64 km deep.

· 64 km deep · released about 120 lb 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 2.4 (md)
Depth
64 km below the surface
Felt
no reports yet
Nearest
Isabela Municipio, 161 km SW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2440 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth it was probably too small to be felt, even directly above it. 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 120 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.4 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 130,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 92,000× the energy of this one
  3. Around the size people start to feel M 3.0 8.2× the energy of this one
  4. This earthquake M 2.4 about 120 lb of TNT

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 4.4 on 2016-10-23 — about 1,000 times the energy of this one.

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

  1. 5.4 106 km N of Brenas, Puerto Rico · 43 km WSW of this epicentre
  2. 5.1 92 km N of Suárez, Puerto Rico · 43 km SE of this epicentre
  3. 5.0 113 km N of Brenas, Puerto Rico · 36 km WSW 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 19.5563, -65.9910. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Isabela Municipio, PR 161 km (100 mi) SW earthquakes near Isabela Municipio

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

Aftershocks so far

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

  1. 3.5 81 km N of San Juan, Puerto Rico
  2. 3.3 108 km N of Suárez, Puerto Rico
  3. 3.9 151 km N of San Juan, Puerto Rico
  4. 3.4 103 km N of San Juan, Puerto Rico
  5. 2.9 76 km NNE of San Juan, Puerto Rico
  6. 3.6 124 km N of Brenas, Puerto Rico
  7. 3.0 Puerto Rico region
  8. 3.2 80 km N of Loíza, Puerto Rico
  9. 3.5 110 km N of Suárez, Puerto Rico
  10. 3.6 127 km N of Suárez, Puerto Rico
  11. 3.4 84 km N of San Juan, Puerto Rico
  12. 3.3 113 km NNE of San Juan, Puerto Rico
  13. 3.7 107 km N of Suárez, Puerto Rico
  14. 3.5 127 km N of Suárez, Puerto Rico
  15. 3.2 94 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.