M4.8 Earthquake in the Bonin Islands, Japan region — October 25, 2026

On October 25, 2026 at 02:36 UTC, a magnitude 4.8 deep-focus earthquake struck in the Bonin Islands, Japan region, at a depth of 498.9 km and coordinates 27.6872°, 139.7389°. This earthquake was detected by 89 seismic stations with good location accuracy and was assigned a USGS significance rating of 354, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 4.8 releases seismic energy equivalent to roughly 239 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.2 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 6.5 mainshock that occurred 2 hours ago in the Bonin Islands, Japan region. Since the mainshock, the USGS has recorded 2 aftershocks in this area. Aftershock activity is expected to continue for weeks to months as stresses on surrounding faults redistribute.

The epicenter is located in Japan, a region characterized by the intersection of four tectonic plates — Pacific, Philippine Sea, Eurasian, and North American — creating multiple subduction zones. The nearest mapped fault system is the Japan Trench. View all earthquakes in Japan.

Learn more: Magnitude scale · Aftershock sequences