5.1

M5.1 Earthquake 270 km WNW of Haveluloto, Tonga — April 23, 2021

2021-04-23 23:11:56 UTC (2021-04-23) · approx. 11:11 AM UTC-12 local

MagnitudeM5.1(mb)
Time23:11 UTC≈ 11:11 AM UTC-12
Depth494.6 kmdeep-focus
Coordinates-20.434°, -177.700°
Felt byNo felt reports
Status✓ Reviewed by USGS

On April 23, 2021 at 23:11 UTC, a magnitude 5.1 deep-focus earthquake struck 270 km WNW of Haveluloto, Tonga, at a depth of 494.6 km and coordinates -20.4345°, -177.6995°.

Physical scale: An earthquake of magnitude 5.1 releases seismic energy equivalent to roughly 674 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 2.0 km — a useful intuition for the size of the slip patch on the fault.

The epicenter is located in Tonga, a region characterized by the Tonga-Kermadec subduction zone, where the Pacific Plate descends at up to 240 mm per year — the fastest plate convergence on Earth. The nearest mapped fault system is the Tonga Trench. View all earthquakes in Tonga.

Learn more: Magnitude scale · Aftershock sequences

Map showing earthquake epicenter at -20.43°, -177.70°

Earthquake Details

Magnitude
5.1 mb
Depth
494.6 km
deep-focus
Location
-20.4345°N
-177.6995°E

Technical Information

Event ID
us6000e46r
Event Type
earthquake
Status
✓ Reviewed
Significance
400
Azimuthal Gap
25.0°
Min Station Distance
4.826°
RMS Residual
0.86 sec
Last Updated
2025-12-22 18:57:01 UTC

Common Questions

How strong was the magnitude 5.1 earthquake near Haveluloto, Tonga?

The magnitude 5.1 earthquake that struck 270 km WNW of Haveluloto, Tonga on April 23, 2021 at 23:11 UTC had a depth of 494.6 km. For context, this was a moderate earthquake that could be widely felt.

Where did the earthquake occur?

The earthquake epicenter was located at -20.4345°, -177.6995°, which is 270 km WNW of Haveluloto, Tonga. View all earthquakes in Tonga.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.1 earthquakes can continue for days to weeks and gradually diminish over time.

Has Tonga had earthquakes this big before?

The largest recorded earthquake in Tonga was the M8.1 Tonga Trench earthquake of June 26, 1917. Today's magnitude 5.1 event is significantly smaller than that historical record.

Authoritative source: USGS event page (event ID: us6000e46r). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, April 23, 2021). M5.1 Earthquake 270 km WNW of Haveluloto, Tonga — April 23, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000e46r/