M4.1 Earthquake 178 km W of Neiafu, Tonga — August 21, 2026
2026-08-21 15:21:18 UTC (2026-08-21) · approx. 3:21 AM UTC-12 local
On August 21, 2026 at 15:21 UTC, a magnitude 4.1 intermediate depth earthquake struck 178 km W of Neiafu, Tonga, at a depth of 271.1 km and coordinates -18.4604°, -175.6580°.
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.
Earthquake Details
-175.6580°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.1 earthquake near Neiafu, Tonga?
The magnitude 4.1 earthquake that struck 178 km W of Neiafu, Tonga on August 21, 2026 at 15:21 UTC had a depth of 271.1 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.
Actions
Location
Understanding This Data
Magnitude 4.1 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000tmj2). 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 178 km W of Neiafu, Tonga — August 21, 2026. Retrieved August 29, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000tmj2/