M4.5 Earthquake 95 km W of Pangai, Tonga — August 25, 2024

On August 25, 2024 at 23:50 UTC, a magnitude 4.5 intermediate depth earthquake struck 95 km W of Pangai, Tonga, at a depth of 100.5 km and coordinates -19.8519°, -175.2630°. This earthquake was detected by 22 seismic stations with good location accuracy and was assigned a USGS significance rating of 312, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 4.5 releases seismic energy equivalent to roughly 85 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 767 m — 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 5.0 mainshock that occurred 16 days ago 65 km WSW of Pangai, Tonga. Since the mainshock, the USGS has recorded 0 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