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M4.8 earthquake 5 km SW of Guánica, Puerto Rico

A magnitude 4.8 earthquake struck 5 km SW of Guánica, Puerto Rico at 09:19 local time (13:19 UTC) on 18 Sept 2026, at a depth of 7 km, according to USGS.

86 reports to USGS “Did You Feel It?”

Data: USGS · updated 2026-09-25 19:30 UTC · reviewed

Magnitude
4.8light
local magnitude (Richter) (ml)
Depth
7 km
Status
Reviewed
Origin time
2026-09-18 13:19:35 UTC
Local: 18 Sept 2026, 09:19:35 (America/Puerto Rico)
Epicentre
17.939° N, 66.945° W

Circles show this event and others within 32 km from 7 days before to 30 days after. Lines: plate boundaries and GEM active faults. Open on the live map

Nearby places

Distance and estimated shaking at nearby places
PlaceDistanceEst. shaking
GuánicaPuerto Rico · pop. 9,2245 kmVIStrong
YaucoPuerto Rico · pop. 20,29514 kmVModerate
PoncePuerto Rico · pop. 137,49135 kmIVLight
MayagüezPuerto Rico · pop. 73,07736 kmIVLight
AreciboPuerto Rico · pop. 87,75464 kmIIIWeak
San JuanPuerto Rico · pop. 418,140106 kmIIWeak
Santo Domingo EsteSanto Domingo Province, Dominican Republic · pop. 700,000313 kmINot felt
Santo DomingoNacional, Dominican Republic · pop. 2,201,941317 kmINot 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 103 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.

AgencyMagnitudeDepthEpicentreTime offsetStatus
USGS · PRheadlinePuerto Rico Seismic Network via U.S. Geological Survey4.8 ml7 km17.94° N, 66.95° W–Reviewed

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How big was it?

Widely felt near the epicentre: rattling windows and objects. Significant damage is unlikely.

It released roughly the energy of 239 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 7 km this was a shallow earthquake, which is felt more strongly at the surface than a deeper one of the same size.

M4.8 releases about 32× the energy of M3.8, and its waves are about 10× taller on a seismogram. Energy: 239 t of TNT vs 7.6 t of TNT.

Each square is the energy of one M3.8. Energy from log₁₀E = 1.5M + 4.8.

Aftershocks and nearby activity

59 later earthquakes within 32 km; the largest was M3.4 10 days ago. 6 in the 7 days before. Aftershock rates usually fall off roughly in proportion to 1/time.

Aftershocks

Mainshock M4.8

59 later earthquakes nearby. Aftershock rates typically fall off roughly as 1/time (Omori's law).

Aftershocks
Time after mainshock (hours)MagnitudeDepth (km)
0.062.58
0.262.910
0.812.68
0.902.59
3.632.68
3.642.78
4.023.46
5.072.88
5.082.56
6.092.76
6.153.07
8.362.58
8.942.57
9.142.67
13.882.59
13.902.513
14.242.57
15.493.07
15.793.18
16.203.18
27.202.88
33.452.69
34.902.57
55.223.08
58.322.57
83.192.111
83.722.215
87.762.017
96.431.811
97.412.17
98.441.87
102.022.28
107.742.18
109.902.27
111.602.117
112.932.57
123.701.78
124.952.314
127.522.18
127.602.37
129.952.08
134.201.99
149.942.112
152.042.68
152.942.46
154.982.37
164.952.09
167.692.17
191.182.49
196.352.18
206.242.16
208.771.27
208.772.08
208.781.27
209.102.37
230.051.77
234.302.27
243.802.017
250.002.37
  1. 3.45 km W of Guánica, Puerto Rico09-18 17:20
  2. 3.15 km SW of Guánica, Puerto Rico09-19 05:06
  3. 3.15 km W of Guánica, Puerto Rico09-19 05:31
  4. 3.05 km WSW of Guánica, Puerto Rico09-18 19:28
  5. 3.04 km SW of Guánica, Puerto Rico09-19 04:49
  6. 3.05 km WSW of Guánica, Puerto Rico09-20 20:32
  7. 2.95 km SW of Guánica, Puerto Rico09-18 13:35
  8. 2.84 km WSW of Guánica, Puerto Rico09-18 18:23
  9. 2.8Near Guánica, Puerto Rico09-19 16:31
  10. 2.75 km W of Guánica, Puerto Rico09-18 19:24
  11. 2.76 km WSW of Guánica, Puerto Rico09-18 16:57
  12. 2.67 km SW of Guánica, Puerto Rico09-24 21:21
  13. 2.63 km SW of Guánica, Puerto Rico09-18 14:08
  14. 2.65 km SW of Guánica, Puerto Rico09-19 22:46
  15. 2.65 km WSW of Guánica, Puerto Rico09-18 22:28
  16. 2.64 km W of Guánica, Puerto Rico09-18 16:57
  17. 2.5Near Guánica, Puerto Rico09-18 21:41
  18. 2.5Near Guánica, Puerto Rico09-18 14:13
  19. 2.55 km SSW of Guánica, Puerto Rico09-18 18:24
  20. 2.54 km W of Guánica, Puerto Rico09-20 00:13
  21. 2.54 km WNW of Guánica, Puerto Rico09-18 13:22
  22. 2.55 km SW of Guánica, Puerto Rico09-23 06:15
  23. 2.54 km W of Guánica, Puerto Rico09-20 23:38
  24. 2.54 km SSW of Guánica, Puerto Rico09-19 03:13
  25. 2.54 km SW of Guánica, Puerto Rico09-19 03:33

Did you feel it?

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Reports on SeismoAtlas

No reports yet.

USGS “Did You Feel It?” has 86 reports: add yours at USGS.

Event id pr2026261000. First recorded here 28 Sept 2026, 17:32:11 UTC. Solutions: USGS · PR (usgs:pr2026261000). Cite as: SeismoAtlas, “M4.8 earthquake 5 km SW of Guánica, Puerto Rico”, https://seismoatlas.com/earthquake/pr2026261000-m4-8-earthquake-5-km-sw-of-guanica-puerto-rico, data from USGS.

JSON: /api/v1/events/pr2026261000. SeismoAtlas is not an official warning service.