Earthquakes in Puerto Rico — September 2026

273 earthquakes were recorded in Puerto Rico during September 2026, an average of 9.1 per day.

2 reached magnitude 4 or above and 0 reached magnitude 5 or above. The average focal depth was 15 km.

The month's largest event in Puerto Rico was a magnitude 4.8 earthquake near Guánica, Puerto Rico on 18 September 2026 at 13:19 UTC. A magnitude 4.8 earthquake radiates roughly 239 tons of TNT equivalent in seismic energy.

That is well above the Puerto Rico monthly average of 176 events over the period we cover — an unusually active month, and up from the 158 recorded the previous month.

96% of events here are shallow (under 70 km), 4% intermediate (70–300 km) and 0% deep-focus (over 300 km). Almost everything here is crustal. That is characteristic of transform faulting or continental deformation rather than subduction — and it means shaking at the surface is strong for the magnitudes involved.

By band, the catalogue holds 51 in the magnitude 1 range, 176 in the magnitude 2 range, 44 in the magnitude 3 range, 2 in the magnitude 4 range.

Activity peaked on 18 September, when 67 events were recorded.

The month's largest events were M4.8 near Guánica, Puerto Rico on 18 September at 7 km; M4.6 near Guánica, Puerto Rico on 18 September at 10 km; M3.8 near Culebra, Puerto Rico on 11 September at 90 km.

That is 55% above the 176 events Puerto Rico averages per month across the 23 months on record.