M4.5 Earthquake 275 km E of Levuka, Fiji — February 23, 2023

On February 23, 2023 at 16:30 UTC, a magnitude 4.5 deep-focus earthquake struck 275 km E of Levuka, Fiji, at a depth of 455.1 km and coordinates -18.3996°, -178.1003°. This earthquake was detected by 33 seismic stations with excellent 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 5.5 mainshock that occurred 19 days ago 283 km E of Levuka, Fiji. Since the mainshock, the USGS has recorded 2 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