QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7md

87 km N of San Antonio, Puerto Rico

Yes. A magnitude 2.7 earthquake was recorded 87 km N of San Antonio, Puerto Rico, at 10:59 pm AST on 21 December 2019 (02:59 UTC), 24 km deep.

· 24 km deep · released about 380 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Aguadilla Municipio 88 kmIsabela Municipio 90 kmQuebradillas Municipio 95 kmAguada Municipio 99 kmCamuy Municipio 100 kmMoca Municipio 100 kmHatillo Municipio 103 kmRincón Municipio 103 kmSan Sebastián Municipio 108 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 2.7 (md)
Depth
24 km below the surface
Felt
no reports yet
Nearest
Aguadilla Municipio, 88 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2440 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 9 km (6 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 380 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 40,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 29,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.5× the energy of this one
  4. This earthquake M 2.7 about 380 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 6.0 on 2019-09-24 — about 80,000 times the energy of this one.

Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:

  1. 7.7 45 km N of San Antonio, Puerto Rico · 42 km SSE of this epicentre
  2. 6.0 93 km NNW of San Antonio, Puerto Rico · 7 km NW of this epicentre
  3. 6.0 81 km N of Isabela, Puerto Rico · 34 km E of this epicentre
  4. 6.0 67 km NNW of San Antonio, Puerto Rico · 21 km S of this epicentre
  5. 5.7 88 km N of San Antonio, Puerto Rico · 1 km N 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 19.2666, -67.2451. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aguadilla Municipio, PR 88 km (55 mi) S earthquakes near Aguadilla Municipio
Isabela Municipio, PR 90 km (56 mi) SSE earthquakes near Isabela Municipio
Quebradillas Municipio, PR 95 km (59 mi) SSE earthquakes near Quebradillas Municipio
Aguada Municipio, PR 99 km (62 mi) S earthquakes near Aguada Municipio
Camuy Municipio, PR 100 km (62 mi) SSE earthquakes near Camuy Municipio
Moca Municipio, PR 100 km (62 mi) S earthquakes near Moca Municipio

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

Aftershocks so far

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

  1. 3.3 94 km NNW of San Antonio, Puerto Rico
  2. 3.0 98 km NE of Punta Cana, Dominican Republic
  3. 3.2 100 km NNW of San Antonio, Puerto Rico
  4. 3.1 75 km N of San Antonio, Puerto Rico
  5. 3.2 57 km N of San Antonio, Puerto Rico
  6. 3.4 100 km NNW of San Antonio, Puerto Rico
  7. 3.2 44 km NNW of San Antonio, Puerto Rico
  8. 3.2 77 km NNW of San Antonio, Puerto Rico
  9. 2.8 107 km N of San Antonio, Puerto Rico
  10. 3.1 73 km N of San Antonio, Puerto Rico
  11. 2.9 108 km NNW of San Antonio, Puerto Rico
  12. 3.0 92 km NNW of San Antonio, Puerto Rico
  13. 3.0 86 km N of San Antonio, Puerto Rico
  14. 3.2 Mona Passage
  15. 3.5 89 km NNW of San Antonio, 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.