Earthquake · reviewed by a seismologist
M 3.0md
Earthquake near San Juan, PR
USGS: 34 km NNE of San Juan, Puerto Rico
41 km (26 mi) N of San Juan, PR · 41 km (25 mi) N of Carolina, PR
- When
- 11:07 pm AST on 4 October 2026 ()
- Where
- 35 km (22 mi) NNE of San Juan, PR · earthquakes near San Juan
- Magnitude
- M 3.0 (md)
- Depth
- 43 km below the surface
- Felt
- no reports yet
- Nearest
- Loíza Municipio, 38 km SSE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2 hours ago
A magnitude 3.0 earthquake was recorded 35 km (22 mi) NNE of San Juan, PR, at 11:07 pm AST on 4 October 2026 (03:07 UTC). This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
How big was it?
This earthquake released about 950 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.0 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 350,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 16,000× the energy of this one
- Magna, Utah 2020 M 5.7 11,000× the energy of this one
- This earthquake M 3.0 about 950 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 4.8 on 2017-08-18 — about 500 times the energy of this one.
Before 2016, the USGS record lists 2 earthquakes of M5 or more within 50 km:
- 5.1 66 km N of Brenas, Puerto Rico · 48 km NW of this epicentre
- 5.0 3 km N of Brenas, Puerto Rico · 44 km SW 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 18.7735, -66.0352. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Loíza Municipio, PR | 38 km (23 mi) | SSE | earthquakes near Loíza Municipio |
| Cataño Municipio, PR | 38 km (24 mi) | SSW | earthquakes near Cataño Municipio |
| Toa Baja Municipio, PR | 39 km (24 mi) | SSW | earthquakes near Toa Baja Municipio |
| San Juan Municipio, PR | 39 km (24 mi) | S | earthquakes near San Juan Municipio |
| Dorado Municipio, PR | 41 km (25 mi) | SW | earthquakes near Dorado Municipio |
| Carolina Municipio, PR | 42 km (26 mi) | S | earthquakes near Carolina Municipio |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
No further earthquakes have been recorded within 50 km since this one.
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.