Earthquakes in Tonga — July 2025

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

17 reached magnitude 4 or above and 3 reached magnitude 5 or above. The average focal depth was 139 km.

The month's largest event in Tonga was a magnitude 5.5 earthquake near ‘Ohonua, Tonga on 06 July 2025 at 20:31 UTC. A magnitude 5.5 earthquake radiates roughly 2,682 tons of TNT equivalent in seismic energy.

That is close to the Tonga monthly average of 18 events over the period we cover, and down from the 26 recorded the previous month.

35% of events here are shallow (under 70 km), 53% intermediate (70–300 km) and 12% 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 14 in the magnitude 4 range, 3 in the magnitude 5 range.

Activity peaked on 15 July, when 3 events were recorded.

The month's largest events were M5.5 near ‘Ohonua, Tonga on 06 July at 10 km; M5.2 near Hihifo, Tonga on 10 July at 184 km; M5.2 near ‘Ohonua, Tonga on 03 July at 10 km.

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