M4.6 Earthquake 291 km WNW of Houma, Tonga — June 18, 2026
2026-06-18 21:09:15 UTC (2026-06-18) · approx. 9:09 AM UTC-12 local
On June 18, 2026 at 21:09 UTC, a magnitude 4.6 deep-focus earthquake struck 291 km WNW of Houma, Tonga, at a depth of 553.8 km and coordinates -19.9011°, -177.7541°. This earthquake was detected by 66 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 326, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.6 releases seismic energy equivalent to roughly 120 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 899 m — 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
-177.7541°E
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Common Questions
How strong was the magnitude 4.6 earthquake near Houma, Tonga?
The magnitude 4.6 earthquake that struck 291 km WNW of Houma, Tonga on June 18, 2026 at 21:09 UTC had a depth of 553.8 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -19.9011°, -177.7541°, which is 291 km WNW of Houma, Tonga. View all earthquakes in Tonga.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.6 earthquakes can continue for several days 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 4.6 event is significantly smaller than that historical record.
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Location
Authoritative source: USGS event page (event ID: us7000sueg). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, June 18, 2026). M4.6 Earthquake 291 km WNW of Houma, Tonga — June 18, 2026. Retrieved July 6, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000sueg/