4.3

M4.3 Earthquake 148 km W of Neiafu, TongaMay 4, 2026

2026-05-04 03:58:51 UTC (1 hour ago) · approx. 3:58 PM UTC-12 local

MagnitudeM4.3(mb)
Time03:58 UTC3:58 PM UTC-12
Depth207.9 kmintermediate depth
Coordinates-18.817°, -175.383°
Felt byNo felt reports
Status✓ Reviewed by USGS

On May 4, 2026 at 03:58 UTC, a magnitude 4.3 intermediate depth earthquake struck 148 km W of Neiafu, Tonga, at a depth of 207.9 km and coordinates -18.8168°, -175.3830°.

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 5.4 mainshock that occurred 21 days ago 147 km W of Neiafu, Tonga. Since the mainshock, the USGS has recorded 4 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 -18.82°, -175.38°

Earthquake Details

Magnitude
4.3 mb
Depth
207.9 km
intermediate depth
Location
-18.8168°N
-175.3830°E

Technical Information

Event ID
us7000si2g
Event Type
earthquake
Status
✓ Reviewed
Significance
284
Stations Used
21
Azimuthal Gap
102.0°
Min Station Distance
5.170°
RMS Residual
0.66 sec
Last Updated
2026-05-04 04:20:47 UTC

Common Questions

How strong was the magnitude 4.3 earthquake near Neiafu, Tonga?

The magnitude 4.3 earthquake that struck 148 km W of Neiafu, Tonga on May 4, 2026 at 03:58 UTC had a depth of 207.9 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 M5.4 one earlier?

No. This magnitude 4.3 earthquake is an aftershock of the larger magnitude 5.4 mainshock that occurred earlier 147 km W of Neiafu, Tonga. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

What should I do after an earthquake?

If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.

Authoritative source: USGS event page (event ID: us7000si2g). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2026, May 4, 2026). M4.3 Earthquake 148 km W of Neiafu, TongaMay 4, 2026. Retrieved May 4, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000si2g/