M3.4 earthquake 80 km NNW of Isabela, Puerto Rico
A magnitude 3.4 earthquake struck 80 km NNW of Isabela, Puerto Rico at 23:10 local time (03:10 UTC) on 4 Sept 2026, at a depth of 6 km, according to USGS.
Data: USGS · updated 2026-09-05 12:28 UTC · reviewed
- Magnitude
- 3.4minor
duration magnitude (md) - Depth
- 6 km
- Status
- Reviewed
- Origin time
- 2026-09-05 03:10:36 UTC
- Local: 4 Sept 2026, 23:10:36 (America/Puerto Rico)
- Epicentre
- 19.102° N, 67.438° W
Circles show this event and others within 30 km from 7 days before to 30 days after. Lines: plate boundaries and GEM active faults. Open on the live map
Nearby places
| Place | Distance | Est. shaking |
|---|---|---|
| IsabelaPuerto Rico · pop. 12,505 | 80 km | INot felt |
| AguadillaPuerto Rico · pop. 16,073 | 81 km | INot felt |
| AreciboPuerto Rico · pop. 87,754 | 103 km | INot felt |
| MayagüezPuerto Rico · pop. 73,077 | 105 km | INot felt |
| Punta CanaLa Altagracia Province, Dominican Republic · pop. 100,023 | 117 km | INot felt |
| BarcelonetaPuerto Rico · pop. 22,322 | 119 km | INot felt |
| San JuanPuerto Rico · pop. 418,140 | 156 km | INot felt |
| Santo Domingo EsteSanto Domingo Province, Dominican Republic · pop. 700,000 | 263 km | INot felt |
Shaking is an estimate from the intensity prediction equation of Allen, Wald & Worden (2012), not an observation. Local ground and buildings can change it by a level or more. Likely felt out to about 22 km.
Every agency's solution
Agencies locate earthquakes with their own stations and methods, so their numbers differ. We match reports of the same event by time, distance and magnitude and show them side by side. The headline uses USGS · PR, which has been reviewed by an analyst.
| Agency | Magnitude | Depth | Epicentre | Time offset | Status |
|---|---|---|---|---|---|
| USGS · PRheadlinePuerto Rico Seismic Network via U.S. Geological Survey | 3.4 md | 6 km | 19.10° N, 67.44° W | – | Reviewed |
How big was it?
Often felt by people at rest close to the epicentre, rarely causes damage.
It released roughly the energy of 1.7 t of TNT. Magnitude is logarithmic: each whole step means about 32 times more energy and 10 times larger waves on a seismogram. Depth matters too: at 6 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.
M3.4 releases about 28× the energy of M2.4, and its waves are about 9.1× taller on a seismogram. Energy: 1.7 t of TNT vs 60 kg of TNT.
Each square is the energy of one M2.4. Energy from log₁₀E = 1.5M + 4.8.
Aftershocks and nearby activity
1 later earthquake within 30 km; the largest was M3.4 15 days ago. 3 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.
Mainshock M3.4
1 later earthquake nearby. Aftershock rates typically fall off roughly as 1/time (Omori's law).
| Time after mainshock (hours) | Magnitude | Depth (km) |
|---|---|---|
| 205.01 | 3.4 | 5 |
Did you feel it?
Reports from people help show where shaking was strong. They are anonymous and shown here in aggregate.
Reports close 14 days after an earthquake.
Reports on SeismoAtlas
No reports yet.
Event id pr71530933. First recorded here 28 Sept 2026, 17:32:12 UTC. Solutions: USGS · PR (usgs:pr71530933). Cite as: SeismoAtlas, “M3.4 earthquake 80 km NNW of Isabela, Puerto Rico”, https://seismoatlas.com/earthquake/pr71530933-m3-4-earthquake-80-km-nnw-of-isabela-puerto-rico, data from USGS.
JSON: /api/v1/events/pr71530933. SeismoAtlas is not an official warning service.