M4.6 Earthquake in the Volcano Islands, Japan region — April 23, 2026

On April 23, 2026 at 16:49 UTC, a magnitude 4.6 shallow crustal earthquake struck in the Volcano Islands, Japan region, at a depth of 10.0 km and coordinates 23.1193°, 142.4501°. This earthquake was detected by 36 seismic stations with good location accuracy and was assigned a USGS significance rating of 326, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 4.6 releases seismic energy equivalent to roughly 120 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 899 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 5.5 mainshock that occurred 7 days ago in the Volcano Islands, Japan region. 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 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