Earthquakes in Tonga — October 2025

8 earthquakes were recorded in Tonga during October 2025, an average of 0.3 per day.

8 reached magnitude 4 or above and 1 reached magnitude 5 or above. The average focal depth was 275 km.

The month's largest event in Tonga was a magnitude 5.2 earthquake near ‘Ohonua, Tonga on 03 October 2025 at 02:43 UTC. A magnitude 5.2 earthquake radiates roughly 951 tons of TNT equivalent in seismic energy.

That is below the Tonga monthly average of 18 events over the period we cover — a comparatively quiet month, and down from the 14 recorded the previous month.

25% of events here are shallow (under 70 km), 38% intermediate (70–300 km) and 38% 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 7 in the magnitude 4 range, 1 in the magnitude 5 range.

Activity peaked on 31 October, when 2 events were recorded.

The month's largest events were M5.2 near ‘Ohonua, Tonga on 03 October at 10 km; M4.8 near Hihifo, Tonga on 31 October at 57 km; M4.7 near Houma, Tonga on 25 October at 541 km.

That is 57% below the 18 events Tonga averages per month across the 21 months on record.