M4.8 Earthquake 100 km NE of Hihifo, Tonga — April 18, 2026
2026-04-18 09:32:01 UTC (1 day ago)
Aftershock of the M5.0 mainshock.
On April 18, 2026 at 09:32 UTC, a magnitude 4.8 shallow crustal earthquake struck 100 km NE of Hihifo, Tonga, at a depth of 10.0 km and coordinates -15.2935°, -173.1530°. This earthquake was detected by 30 seismic stations with good location accuracy and was assigned a USGS significance rating of 354, placing it among routine seismic activity.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.0 mainshock that occurred 27 days ago 125 km NE of Hihifo, Tonga. Since the mainshock, the USGS has recorded 7 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
-173.1530°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.8 earthquake near Hihifo, Tonga?
The magnitude 4.8 earthquake that struck 100 km NE of Hihifo, Tonga on April 18, 2026 at 09:32 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 -15.2935°, -173.1530°, which is 100 km NE of Hihifo, Tonga. View all earthquakes in Tonga.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.8 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.0 one earlier?
No. This magnitude 4.8 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier 125 km NE of Hihifo, 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 4.8 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.