QuakeIndex

Earthquake · reviewed by a seismologist

M 3.4md

103 km N of Isabela, Puerto Rico

Yes. A magnitude 3.4 earthquake was recorded 103 km N of Isabela, Puerto Rico, at 10:00 pm AST on 17 April 2020 (02:00 UTC), 10 km deep. 2 people have reported feeling it to USGS.

· 10 km deep · released about 1.7 tons of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Aguadilla Municipio 105 kmIsabela Municipio 106 kmQuebradillas Municipio 110 kmCamuy Municipio 114 kmHatillo Municipio 117 kmAguada Municipio 117 kmMoca Municipio 117 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
10 km below the surface
Felt
2 reports · strongest reported intensity IV
Nearest
Aguadilla Municipio, 105 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 2316 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 55 km (34 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 1.7 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 99,000× the energy of this one
  2. Mineral, Virginia 2011 M 5.8 4,400× the energy of this one
  3. Magna, Utah 2020 M 5.7 3,100× the energy of this one
  4. This earthquake M 3.4 about 1.7 tons of TNT
  5. Around the size people start to feel M 3.0 this one released 3.6× 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 8,800 times the energy of this one.

Before 2016, the USGS record lists 7 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.0 93 km NNW of San Antonio, Puerto Rico · 17 km SW of this epicentre
  2. 6.0 81 km N of Isabela, Puerto Rico · 34 km SE of this epicentre
  3. 6.0 67 km NNW of San Antonio, Puerto Rico · 40 km SSW of this epicentre
  4. 5.7 88 km N of San Antonio, Puerto Rico · 18 km SSW of this epicentre
  5. 5.5 65 km N of Isabela, Puerto Rico · 38 km SSE 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 19.4278, -67.1768. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Aguadilla Municipio, PR 105 km (66 mi) S earthquakes near Aguadilla Municipio
Isabela Municipio, PR 106 km (66 mi) S earthquakes near Isabela Municipio
Quebradillas Municipio, PR 110 km (68 mi) SSE earthquakes near Quebradillas Municipio
Camuy Municipio, PR 114 km (71 mi) SSE earthquakes near Camuy Municipio
Hatillo Municipio, PR 117 km (73 mi) SSE earthquakes near Hatillo Municipio
Aguada Municipio, PR 117 km (73 mi) S earthquakes near Aguada Municipio

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

Aftershocks so far

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

  1. 3.5 93 km NNW of San Antonio, Puerto Rico
  2. 3.2 90 km NNW of San Antonio, Puerto Rico
  3. 3.5 79 km NNW of San Antonio, Puerto Rico
  4. 3.6 106 km NNW of San Antonio, Puerto Rico
  5. 3.4 87 km NNW of San Antonio, Puerto Rico
  6. 1.9 65 km N of San Antonio, Puerto Rico
  7. 3.4 75 km N of San Antonio, Puerto Rico
  8. 3.5 82 km NNW of San Antonio, Puerto Rico
  9. 3.5 95 km NNW of San Antonio, Puerto Rico
  10. 3.3 73 km NNW of San Antonio, Puerto Rico
  11. 3.6 71 km N of San Antonio, Puerto Rico
  12. 3.4 86 km N of San Antonio, Puerto Rico
  13. 4.1 79 km N of San Antonio, Puerto Rico
  14. 3.4 56 km N of San Antonio, Puerto Rico
  15. 3.4 90 km N 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.