M4.9 Earthquake 200 km S of ‘Ohonua, Tonga — April 28, 2026
2026-04-28 16:18:24 UTC (3 hours ago) · approx. 4:18 AM UTC-12 local
On April 28, 2026 at 16:18 UTC, a magnitude 4.9 shallow crustal earthquake struck 200 km S of ‘Ohonua, Tonga, at a depth of 10.0 km and coordinates -23.1275°, -175.2728°. This earthquake was detected by 44 seismic stations with good location accuracy and was assigned a USGS significance rating of 369, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 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
-175.2728°E
Technical Information
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Common Questions
How strong was the magnitude 4.9 earthquake near ‘Ohonua, Tonga?
The magnitude 4.9 earthquake that struck 200 km S of ‘Ohonua, Tonga on April 28, 2026 at 16:18 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -23.1275°, -175.2728°, which is 200 km S of ‘Ohonua, Tonga. View all earthquakes in Tonga.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 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 4.9 event is significantly smaller than that historical record.
What should I do after an earthquake?
If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.
Authoritative source: USGS event page (event ID: us7000sgqy). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, April 28, 2026). M4.9 Earthquake 200 km S of ‘Ohonua, Tonga — April 28, 2026. Retrieved April 28, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000sgqy/