QuakeIndex

Earthquake · reviewed by a seismologist

M 3.4md

100 km NNW of San Antonio, Puerto Rico

Yes. A magnitude 3.4 earthquake was recorded 100 km NNW of San Antonio, Puerto Rico, at 3:53 am AST on 24 December 2019 (07:53 UTC), 23 km deep.

· 23 km deep · released about 2 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Aguadilla Municipio 101 kmIsabela Municipio 104 kmQuebradillas Municipio 109 kmAguada Municipio 112 kmMoca Municipio 114 kmCamuy Municipio 114 kmRincón Municipio 115 kmHatillo Municipio 118 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 3.4 (md)
Depth
23 km below the surface
Felt
no reports yet
Nearest
Aguadilla Municipio, 101 km SSE
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2433 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 53 km (33 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 2 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.4 would have released about 32 times as much.

  1. Northridge, California 1994 M 6.7 86,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 3,800× the energy of this one
  3. Magna, Utah 2020 M 5.7 2,700× the energy of this one
  4. This earthquake M 3.4 about 2 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 4.1× 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 6.0 on 2019-09-24 — about 7,700 times the energy of this one.

Before 2016, the USGS record lists 10 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.8 94 km NE of Punta Cana, Dominican Republic · 48 km WSW of this epicentre
  2. 6.0 93 km NNW of San Antonio, Puerto Rico · 8 km SE of this epicentre
  3. 6.0 81 km N of Isabela, Puerto Rico · 45 km ESE of this epicentre
  4. 6.0 67 km NNW of San Antonio, Puerto Rico · 33 km SSE of this epicentre
  5. 5.7 88 km N of San Antonio, Puerto Rico · 14 km SE 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 19.3703, -67.3328. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aguadilla Municipio, PR 101 km (63 mi) SSE earthquakes near Aguadilla Municipio
Isabela Municipio, PR 104 km (65 mi) SSE earthquakes near Isabela Municipio
Quebradillas Municipio, PR 109 km (68 mi) SSE earthquakes near Quebradillas Municipio
Aguada Municipio, PR 112 km (69 mi) S earthquakes near Aguada Municipio
Moca Municipio, PR 114 km (71 mi) SSE earthquakes near Moca Municipio
Camuy Municipio, PR 114 km (71 mi) SSE earthquakes near Camuy Municipio

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

Aftershocks so far

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

  1. 2.9 102 km NE of Punta Cana, Dominican Republic
  2. 3.0 86 km N of Isabela, Puerto Rico
  3. 2.9 96 km NE of Punta Cana, Dominican Republic
  4. 2.2 90 km N of Isabela, Puerto Rico
  5. 2.8 90 km N of San Antonio, Puerto Rico
  6. 3.0 68 km NNW of San Antonio, Puerto Rico
  7. 2.7 84 km NW of San Antonio, Puerto Rico
  8. 2.7 71 km N of San Antonio, Puerto Rico
  9. 2.5 64 km N of Isabela, Puerto Rico
  10. 2.8 80 km N of Isabela, Puerto Rico
  11. 2.6 101 km NE of Punta Cana, Dominican Republic
  12. 3.0 84 km N of Isabela, Puerto Rico
  13. 3.0 91 km NNW of San Antonio, Puerto Rico
  14. 2.9 97 km NNW of San Antonio, Puerto Rico
  15. 2.7 98 km N of Isabela, 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.