Earthquakes in Tonga — May 2025

24 earthquakes were recorded in Tonga during May 2025, an average of 0.8 per day.

24 reached magnitude 4 or above and 6 reached magnitude 5 or above. The average focal depth was 185 km.

The month's largest event in Tonga was a magnitude 6.4 earthquake near Neiafu, Tonga on 14 May 2025 at 04:15 UTC. A magnitude 6.4 earthquake radiates roughly 60,036 tons of TNT equivalent in seismic energy.

That is well above the Tonga monthly average of 18 events over the period we cover — an unusually active month, and down from the 26 recorded the previous month.

29% of events here are shallow (under 70 km), 50% intermediate (70–300 km) and 21% deep-focus (over 300 km). That proportion of deep-focus events is the signature of a subduction zone: only a cold slab descending into the mantle stays brittle enough to rupture at those depths.

By band, the catalogue holds 18 in the magnitude 4 range, 4 in the magnitude 5 range, 2 in the magnitude 6 range.

Activity peaked on 06 May, when 3 events were recorded.

The month's largest events were M6.4 near Neiafu, Tonga on 14 May at 243 km; M6.0 near ‘Ohonua, Tonga on 25 May at 12 km; M5.5 near Pangai, Tonga on 11 May at 10 km.

That is 30% above the 18 events Tonga averages per month across the 21 months on record.