M5.5 Earthquake south of the Fiji Islands — March 22, 2025

On March 22, 2025 at 01:15 UTC, a magnitude 5.5 deep-focus earthquake struck south of the Fiji Islands, at a depth of 347.3 km and coordinates -26.0219°, -178.7644°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. This earthquake was detected by 88 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 465, placing it among routine seismic activity.

Physical scale: An earthquake of magnitude 5.5 releases seismic energy equivalent to roughly 3 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 3.8 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 5.8 mainshock that occurred 13 days ago south of the Fiji Islands. 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 Fiji, a region characterized by the Fiji Fracture Zone at the junction of the Pacific and Australian plates, with deep-focus seismicity from the subducted slab. View all earthquakes in Fiji.

Learn more: Magnitude scale · Aftershock sequences