Earthquakes in Tonga — April 2025

25 earthquakes were recorded in Tonga during April 2025, an average of 0.8 per day.

25 reached magnitude 4 or above and 10 reached magnitude 5 or above. The average focal depth was 133 km.

The month's largest event in Tonga was a magnitude 5.7 earthquake near Hihifo, Tonga on 04 April 2025 at 08:01 UTC. A magnitude 5.7 earthquake radiates roughly 5,351 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 up from the 21 recorded the previous month.

52% of events here are shallow (under 70 km), 40% intermediate (70–300 km) and 8% 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 15 in the magnitude 4 range, 10 in the magnitude 5 range.

Activity peaked on 02 April, when 3 events were recorded.

The month's largest events were M5.7 near Hihifo, Tonga on 04 April at 192 km; M5.3 near Hihifo, Tonga on 12 April at 73 km; M5.3 near ‘Ohonua, Tonga on 25 April at 10 km.

That is 35% above the 18 events Tonga averages per month across the 21 months on record.