Seismic Activity in the Tonga Subduction Zone: The November 2022 Magnitude 7.3 Earthquake

Tonga lies along the Tonga-Kermadec subduction zone, one of the most seismically active regions on Earth. Here the Pacific Plate converges with and subducts beneath the Australian Plate at rates exceeding 15 cm per year, forming the Tonga Trench and driving frequent earthquakes and volcanic activity. The island arc sits within the Pacific Ring of Fire, where intermediate-depth events between 30 and 70 km are common as the downgoing slab deforms. On 11 November 2022 at 10:48 UTC, a magnitude 7.3 earthquake struck approximately 205 km east-southeast of Neiafu, Tonga, at a depth of 37 km. This event occurred within the subducting Pacific Plate and released significant energy consistent with thrust faulting typical of the region’s tectonics. No major tsunami was generated, and impacts remained limited owing to the offshore location and moderate depth. The Tonga region has experienced recurrent large earthquakes throughout recorded history, reflecting ongoing plate convergence. Volcanic processes are intimately linked; the January 2022 Hunga Tonga–Hunga Ha’apai eruption illustrated the interplay between subduction-driven magmatism and seismicity. Monitoring by regional seismic networks continues to track aftershock sequences and slab dynamics, improving hazard assessment for nearby island communities.

References

USGS Earthquake Catalog Global CMT Project Tonga Geological Services reports