Earthquake · reviewed by a seismologist
M 3.1md
Earthquake near San Juan, PR
No earthquake was likely felt in San Juan in the 24 hours to 6:57 pm AST (22:57 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 3.1 earthquake was recorded 35 km (22 mi) southwest of San Juan, PR, at 5:00 am AST on 19 August 2017 (09:00 UTC), 32 km deep.
USGS: 5 km NE of Orocovis, Puerto Rico
35 km (21 mi) WSW of San Juan, PR · 24 km (15 mi) WSW of Bayamón, PR
- When
- 5:00 am AST on 19 August 2017 ()
- Where
- 35 km (22 mi) southwest of San Juan, PR · earthquakes near San Juan
- Magnitude
- M 3.1 (md)
- Depth
- 32 km below the surface
- Felt
- no reports yet
- Nearest
- Corozal Municipio, 6 km NNE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 3285 days ago
Earthquake alerts for San Juan, PR
Get a notification in this browser when USGS records an earthquake near San Juan, PR. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 24 km (15 mi) from the epicentre. 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.
Likely felt in: Corozal 10 km, intensity II · Ciales 15 km, intensity II · Coamo 20 km, intensity II · Vega Baja 21 km, intensity II · San Antonio 22 km, intensity II · Dorado 24 km, intensity II · Sumidero 24 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 1,200 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.1 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 280,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 12,000× the energy of this one
- Magna, Utah 2020 M 5.7 8,800× the energy of this one
- This earthquake M 3.1 about 1,200 lb of TNT
- Around the size people start to feel M 3.0 this one released 1.3× 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
No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 5.8 12 km N of Garrochales, Puerto Rico · 40 km NNW of this epicentre
- 5.1 3 km W of Aguas Buenas, Puerto Rico · 23 km E of this epicentre
- 5.0 3 km N of Brenas, Puerto Rico · 27 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 18.2610, -66.3536. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Corozal Municipio, PR | 6 km (3 mi) | NNE | earthquakes near Corozal Municipio |
| Barranquitas Municipio, PR | 8 km (5 mi) | SE | earthquakes near Barranquitas Municipio |
| Morovis Municipio, PR | 9 km (6 mi) | NW | earthquakes near Morovis Municipio |
| Orocovis Municipio, PR | 10 km (6 mi) | WSW | earthquakes near Orocovis Municipio |
| Naranjito Municipio, PR | 11 km (7 mi) | ENE | earthquakes near Naranjito Municipio |
| Comerío Municipio, PR | 15 km (9 mi) | ESE | earthquakes near Comerío Municipio |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
37 earthquakes have been recorded within 50 km since this one.
- 3.0 4 km SSE of Cayey, Puerto Rico
- 1.9 3 km NNW of Potala Pastillo, Puerto Rico
- 1.6 1 km E of Capitanejo, Puerto Rico
- 2.7 11 km S of Jauca, Puerto Rico
- 2.4 1 km SSW of Potala Pastillo, Puerto Rico
- 2.2 6 km SSE of Jauca, Puerto Rico
- 2.9 7 km S of Jauca, Puerto Rico
- 3.1 12 km S of Santa Isabel, Puerto Rico
- 3.1 Puerto Rico region
- 3.3 12 km NNE of Tierras Nuevas Poniente, Puerto Rico
- 2.5 5 km E of Bayamon, Puerto Rico
- 3.1 1 km SW of Trujillo Alto, Puerto Rico
- 2.4 3 km SW of Santa Isabel, Puerto Rico
- 2.5 2 km ESE of Mariano Colón, Puerto Rico
- 2.3 3 km WNW of Santo Domingo, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.