Strong M7.1 earthquake hits Tonga, potential tsunami threat
A strong earthquake registered by the USGS as M7.1 hit off the coast of Pangai, Tonga, at 12:18 UTC on March 30, 2025. The agency is reporting a depth of 10 km (6.2 miles). EMSC is reporting the same magnitude and depth.
Image credit: TW/SAM, Google
The epicenter was located 90 km (56 miles) SW of Pangai (population 1 738) and 169 km (105 miles) WNW of Nuku’alofa (population 22 400), Tonga
1 000 people are estimated to have felt strong shaking, 38 000 moderate, and 65 000 light.
Based on preliminary earthquake parameters (M7.3), hazardous tsunami waves are possible for coasts located within 300 km (185 miles) of the earthquake epicenter, NWS PTWC said at 12:29 UTC.
The tsunami threat from this earthquake has now passed, PTWC reported at 13:22 UTC.
The USGS issued a Green alert for shaking-related fatalities and economic losses. There is a low likelihood of casualties and damage.
Overall, the population in this region resides in structures that are highly vulnerable to earthquake shaking, though some resistant structures exist. The predominant vulnerable building types are unknown/miscellaneous types and wood construction.
Recent earthquakes in this area have caused secondary hazards, such as tsunamis, that might have contributed to losses.
Update
09:30 UTC, March 31
The quake was followed by multiple strong aftershocks, including M6.2 at 15:04 and M5.8 at 15:33 UTC.
Estimated population exposure to earthquake shaking
Selected cities exposed
Regional seismicity
References:
1 M7.1 earthquake Tonga – USGS – March 30, 2025
2 M7.1 earthquake Tonga – EMSC – March 30, 2025
3 M7.3 earthquake Tonga – Tsunami Threat Message – PTWC – March 30, 2025
Teo Blašković founded The Watchers in 2011 and edited it until 2026, covering seismic and volcanic activity, extreme weather, space weather and near-Earth objects. Articles on this page are his archive.
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