QuakeIndex

Earthquake · reviewed by a seismologist

M 2.7md

Earthquake near San Juan, PR

No earthquake was likely felt in San Juan in the 24 hours to 12:52 pm AST (16:52 UTC). The last one was M 4.1, 99 km (62 mi) SE, at 5:44 am AST on 28 October 2026, estimated intensity II (weak) in town; 5 felt reports to USGS. Every earthquake near San Juan

This page: a magnitude 2.7 earthquake was recorded 35 km (22 mi) northeast of San Juan, PR, at 9:01 am AST on 9 August 2017 (13:01 UTC), 50 km deep. 1 person has reported feeling it to USGS.

USGS: 30 km N of Loíza, Puerto Rico

38 km (23 mi) NNE of San Juan, PR · 34 km (21 mi) NNE of Carolina, PR

9:01 am AST, Aug 9, 2017 · · 50 km deep · released about 360 lb of TNT

Every earthquake near San Juan Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Loíza Municipio 29 kmCarolina Municipio 35 kmSan Juan Municipio 36 kmRío Grande Municipio 38 kmCataño Municipio 39 kmCanóvanas Municipio 42 kmToa Baja Municipio 42 kmLuquillo Municipio 42 kmTrujillo Alto Municipio 43 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
9:01 am AST on 9 August 2017 ()
Where
35 km (22 mi) northeast of San Juan, PR · earthquakes near San Juan
Magnitude
M 2.7 (md)
Depth
50 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Loíza Municipio, 29 km S
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1557 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 it was probably too small to be felt, even directly above it. In San Juan, 35 km away, the estimate is intensity II (weak). 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 360 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 42,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 30,000× the energy of this one
  3. Around the size people start to feel M 3.0 2.6× the energy of this one
  4. This earthquake M 2.7 about 360 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.

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 18.7036, -65.8933. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Loíza Municipio, PR 29 km (18 mi) S earthquakes near Loíza Municipio
Carolina Municipio, PR 35 km (22 mi) SSW earthquakes near Carolina Municipio
San Juan Municipio, PR 36 km (23 mi) SSW earthquakes near San Juan Municipio
Río Grande Municipio, PR 38 km (23 mi) SSE earthquakes near Río Grande Municipio
Cataño Municipio, PR 39 km (25 mi) SW earthquakes near Cataño Municipio
Canóvanas Municipio, PR 42 km (26 mi) S earthquakes near Canóvanas Municipio

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

Aftershocks so far

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

  1. 2.8 71 km N of Suárez, Puerto Rico
  2. 2.9 53 km NNW of San Juan, Puerto Rico
  3. 3.1 62 km N of Loíza, Puerto Rico
  4. 2.0 3 km SSE of Carolina, Puerto Rico
  5. 3.2 41 km N of Brenas, Puerto Rico
  6. 3.2 57 km N of San Juan, Puerto Rico
  7. 2.9 1 km WSW of Cataño, Puerto Rico
  8. 3.3 4 km NE of Brenas, Puerto Rico
  9. 3.1 1 km SW of Trujillo Alto, Puerto Rico
  10. 3.3 74 km N of San Juan, Puerto Rico
  11. 2.9 24 km N of Loíza, Puerto Rico
  12. 3.0 67 km NNE of Suárez, Puerto Rico
  13. 3.1 47 km N of Loíza, Puerto Rico
  14. 3.0 44 km N of Loíza, Puerto Rico
  15. 2.9 76 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.