4.1

M4.1 Earthquake 160 km W of Neiafu, TongaAugust 21, 2026

2026-08-21 13:26:17 UTC (2026-08-21) · approx. 1:26 AM UTC-12 local

MagnitudeM4.1(mb)
Time13:26 UTC1:26 AM UTC-12
Depth272.2 kmintermediate depth
Coordinates-18.416°, -175.485°
Felt byNo felt reports
Status✓ Reviewed by USGS

On August 21, 2026 at 13:26 UTC, a magnitude 4.1 intermediate depth earthquake struck 160 km W of Neiafu, Tonga, at a depth of 272.2 km and coordinates -18.4155°, -175.4853°.

Physical scale: An earthquake of magnitude 4.1 releases seismic energy equivalent to roughly 21 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 406 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at -18.42°, -175.49°

Earthquake Details

Magnitude
4.1 mb
Depth
272.2 km
intermediate depth
Location
-18.4155°N
-175.4853°E

Technical Information

Event ID
us7000tcb4
Event Type
earthquake
Status
✓ Reviewed
Significance
259
Stations Used
18
Azimuthal Gap
141.0°
Min Station Distance
5.275°
RMS Residual
0.69 sec
Last Updated
2026-08-29 20:35:03 UTC

Common Questions

How strong was the magnitude 4.1 earthquake near Neiafu, Tonga?

The magnitude 4.1 earthquake that struck 160 km W of Neiafu, Tonga on August 21, 2026 at 13:26 UTC had a depth of 272.2 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 4.1 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 4.1 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000tcb4). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2026, August 21, 2026). M4.1 Earthquake 160 km W of Neiafu, TongaAugust 21, 2026. Retrieved August 29, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000tcb4/