Earthquakes in Tonga — March 2025

21 earthquakes were recorded in Tonga during March 2025, an average of 0.7 per day.

21 reached magnitude 4 or above and 6 reached magnitude 5 or above. The average focal depth was 95 km.

The month's largest event in Tonga was a magnitude 7.3 earthquake near Pangai, Tonga on 30 March 2025 at 12:18 UTC. A magnitude 7.3 earthquake radiates roughly 1.3 million 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 21 recorded the previous month.

71% of events here are shallow (under 70 km), 19% intermediate (70–300 km) and 10% 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, 3 in the magnitude 5 range, 1 in the magnitude 6 range, 2 in the magnitude 7 range.

Activity peaked on 30 March, when 10 events were recorded.

2 event(s) this month carry a USGS link to NOAA tsunami information; the flag does not indicate whether a tsunami occurred.

The month's largest events were M7.3 near Pangai, Tonga on 30 March at 55 km; M7.0 near Pangai, Tonga on 30 March at 10 km; M6.1 near Pangai, Tonga on 30 March at 10 km.

That is 14% above the 18 events Tonga averages per month across the 21 months on record.