M4.2 Earthquake in the Fiji region — September 8, 2025
2025-09-08 18:38:22 UTC (2025-09-08) · approx. 6:38 AM UTC-12 local
On September 8, 2025 at 18:38 UTC, a magnitude 4.2 deep-focus earthquake struck in the Fiji region, at a depth of 591.2 km and coordinates -20.5989°, -178.4263°.
Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 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 Fiji region. 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.
Earthquake Details
-178.4263°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.2 earthquake in the Fiji region?
The magnitude 4.2 earthquake that struck in the Fiji region on September 8, 2025 at 18:38 UTC had a depth of 591.2 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.2 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.5 one earlier?
No. This magnitude 4.2 earthquake is an aftershock of the larger magnitude 5.5 mainshock that occurred earlier in the Fiji region. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Actions
Location
Understanding This Data
Magnitude 4.2 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000quun). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, September 8, 2025). M4.2 Earthquake in the Fiji region — September 8, 2025. Retrieved November 30, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000quun/