4.3

M4.3 Earthquake in the Fiji regionAugust 3, 2025

2025-08-03 22:28:08 UTC (2025-08-03) · approx. 10:28 AM UTC-12 local

MagnitudeM4.3(mb)
Time22:28 UTC10:28 AM UTC-12
Depth554.9 kmdeep-focus
Coordinates-20.474°, -178.296°
Felt byNo felt reports
Status✓ Reviewed by USGS

On August 3, 2025 at 22:28 UTC, a magnitude 4.3 deep-focus earthquake struck in the Fiji region, at a depth of 554.9 km and coordinates -20.4738°, -178.2955°.

Physical scale: An earthquake of magnitude 4.3 releases seismic energy equivalent to roughly 43 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 558 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 8 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.

Map showing earthquake epicenter at -20.47°, -178.30°

Earthquake Details

Magnitude
4.3 mb
Depth
554.9 km
deep-focus
Location
-20.4738°N
-178.2955°E

Technical Information

Event ID
us7000qr4r
Event Type
earthquake
Status
✓ Reviewed
Significance
284
Stations Used
21
Azimuthal Gap
167.0°
Min Station Distance
4.392°
RMS Residual
0.39 sec
Last Updated
2025-10-17 22:51:42 UTC

Common Questions

How strong was the magnitude 4.3 earthquake in the Fiji region?

The magnitude 4.3 earthquake that struck in the Fiji region on August 3, 2025 at 22:28 UTC had a depth of 554.9 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 4.3 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 4.3 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.

Understanding This Data

Magnitude 4.3 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000qr4r). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2025, August 3, 2025). M4.3 Earthquake in the Fiji regionAugust 3, 2025. Retrieved October 17, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000qr4r/