Earthquakes in Tonga — June 2025

24 earthquakes were recorded in Tonga during June 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 184 km.

The month's largest event in Tonga was a magnitude 5.9 earthquake near Houma, Tonga on 06 June 2025 at 19:28 UTC. A magnitude 5.9 earthquake radiates roughly 10,676 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 level with the 24 recorded the previous month.

33% of events here are shallow (under 70 km), 42% intermediate (70–300 km) and 25% 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, 6 in the magnitude 5 range.

Activity peaked on 17 June, when 2 events were recorded.

The month's largest events were M5.9 near Houma, Tonga on 06 June at 359 km; M5.5 near Houma, Tonga on 28 June at 238 km; M5.3 near Houma, Tonga on 25 June at 201 km.

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