M4.5 Earthquake 150 km W of Neiafu, Tonga — April 16, 2026
2026-04-16 23:38:48 UTC (2 days ago)
Aftershock of the M5.5 mainshock.
On April 16, 2026 at 23:38 UTC, a magnitude 4.5 intermediate depth earthquake struck 150 km W of Neiafu, Tonga, at a depth of 219.9 km and coordinates -18.6205°, -175.4086°. This earthquake was detected by 39 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 312, placing it among routine seismic activity.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.5 mainshock that occurred 6 days ago 154 km W of Neiafu, Tonga. Since the mainshock, the USGS has recorded 9 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
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
-175.4086°E
Technical Information
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Common Questions
How strong was the magnitude 4.5 earthquake near Neiafu, Tonga?
The magnitude 4.5 earthquake that struck 150 km W of Neiafu, Tonga on April 16, 2026 at 23:38 UTC had a depth of 219.9 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -18.6205°, -175.4086°, which is 150 km W of Neiafu, Tonga. View all earthquakes in Tonga.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.5 one earlier?
No. This magnitude 4.5 earthquake is an aftershock of the larger magnitude 5.5 mainshock that occurred earlier 154 km W of Neiafu, Tonga. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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 4.5 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.