Earthquakes in Puerto Rico — September 2025

121 earthquakes were recorded in Puerto Rico during September 2025, an average of 4.0 per day.

4 reached magnitude 4 or above and 0 reached magnitude 5 or above. The average focal depth was 21 km.

The month's largest event in Puerto Rico was a magnitude 4.4 earthquake near Isabela, Puerto Rico on 30 September 2025 at 10:07 UTC. A magnitude 4.4 earthquake radiates roughly 60 tons of TNT equivalent in seismic energy.

That is below the Puerto Rico monthly average of 173 events over the period we cover — a comparatively quiet month, and down from the 185 recorded the previous month.

98% of events here are shallow (under 70 km), 2% 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 7 in the magnitude 1 range, 81 in the magnitude 2 range, 29 in the magnitude 3 range, 4 in the magnitude 4 range.

Activity peaked on 08 September, when 8 events were recorded.

The month's largest events were M4.4 near Isabela, Puerto Rico on 30 September at 25 km; M4.2 near Isabela, Puerto Rico on 30 September at 39 km; M4.2 near Suárez, Puerto Rico on 23 September at 35 km.

That is 30% below the 173 events Puerto Rico averages per month across the 21 months on record.