M5.1 Earthquake 221 km SE of Hihifo, Tonga — August 23, 2025
2025-08-23 15:49:54 UTC (2025-08-23) · approx. 4:49 AM UTC-11 local
On August 23, 2025 at 15:49 UTC, a magnitude 5.1 shallow crustal earthquake struck 221 km SE of Hihifo, Tonga, at a depth of 10.0 km and coordinates -17.1324°, -172.1242°. This earthquake was detected by 145 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 400, placing it among routine seismic activity.
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
Earthquake Details
-172.1242°E
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Common Questions
How strong was the magnitude 5.1 earthquake near Hihifo, Tonga?
The magnitude 5.1 earthquake that struck 221 km SE of Hihifo, Tonga on August 23, 2025 at 15:49 UTC had a depth of 10.0 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -17.1324°, -172.1242°, which is 221 km SE of Hihifo, 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.
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Location
Authoritative source: USGS event page (event ID: us6000r3ck). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, August 23, 2025). M5.1 Earthquake 221 km SE of Hihifo, Tonga — August 23, 2025. Retrieved November 12, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000r3ck/