M5.0 Earthquake 95 km NNE of Hihifo, Tonga — October 27, 2026

On October 27, 2026 at 09:07 UTC, a magnitude 5.0 shallow crustal earthquake struck 95 km NNE of Hihifo, Tonga, at a depth of 10.0 km and coordinates -15.1739°, -173.4094°. This earthquake was detected by 40 seismic stations with good location accuracy and was assigned a USGS significance rating of 385, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 5.0 releases seismic energy equivalent to roughly 477 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.7 km — a useful intuition for the size of the slip patch on the fault.

This earthquake is part of an ongoing aftershock sequence following the magnitude 5.2 mainshock that occurred 11 days ago 92 km NNE of Hihifo, Tonga. Since the mainshock, the USGS has recorded 2 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.

The epicenter is located in Tonga, a region characterized by the Tonga-Kermadec subduction zone, where the Pacific Plate descends at up to 240 mm per year — the fastest plate convergence on Earth. The nearest mapped fault system is the Tonga Trench. View all earthquakes in Tonga.

Learn more: Magnitude scale · Aftershock sequences