Earthquakes in Tonga — August 2025

17 earthquakes were recorded in Tonga during August 2025, an average of 0.5 per day.

17 reached magnitude 4 or above and 8 reached magnitude 5 or above. The average focal depth was 157 km.

The month's largest event in Tonga was a magnitude 5.7 earthquake near Neiafu, Tonga on 14 August 2025 at 04:38 UTC. A magnitude 5.7 earthquake radiates roughly 5,351 tons of TNT equivalent in seismic energy.

That is close to the Tonga monthly average of 18 events over the period we cover, and level with the 17 recorded the previous month.

41% of events here are shallow (under 70 km), 41% intermediate (70–300 km) and 18% 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 9 in the magnitude 4 range, 8 in the magnitude 5 range.

Activity peaked on 14 August, when 3 events were recorded.

The month's largest events were M5.7 near Neiafu, Tonga on 14 August at 101 km; M5.6 near Hihifo, Tonga on 18 August at 89 km; M5.6 near Neiafu, Tonga on 14 August at 10 km.

That is close to the 18 events Tonga averages per month across the 21 months on record.