M6.3 Earthquake southeast of the Loyalty Islands — July 13, 2026

On July 13, 2026 at 14:45 UTC, a magnitude 6.3 shallow crustal earthquake struck southeast of the Loyalty Islands, at a depth of 10.0 km and coordinates -22.7889°, 171.5199°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. This earthquake was detected by 81 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 611, making it a moderate-impact event.

Physical scale: An earthquake of magnitude 6.3 releases seismic energy equivalent to roughly 43 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 13 km — a useful intuition for the size of the slip patch on the fault.

Active aftershock sequence: This earthquake is the mainshock of an ongoing aftershock sequence. In the 7 hours since the mainshock, the USGS has recorded 6 aftershocks within 20 km of the epicenter, including 6 of magnitude 3.0 or greater. The strongest aftershock was a magnitude 5.1 event 5 hours ago. Aftershock sequences from mainshocks of magnitude 6.3 typically continue for weeks to months and gradually diminish over time, though occasional larger aftershocks remain possible.