M5.6 Earthquake 135 km NE of Hihifo, Tonga — March 22, 2026
2026-03-22 16:00:18 UTC (2026-03-22) · approx. 4:00 AM UTC-12 local
On March 22, 2026 at 16:00 UTC, a magnitude 5.6 shallow crustal earthquake struck 135 km NE of Hihifo, Tonga, at a depth of 10.0 km and coordinates -14.9521°, -173.0721°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. This earthquake was detected by 17 seismic stations with good location accuracy and was assigned a USGS significance rating of 482, placing it among routine seismic activity. The nearest populated place is Nofoali`i (population 2,018).
Physical scale: An earthquake of magnitude 5.6 releases seismic energy equivalent to roughly 4 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 4.4 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
Nearest Populated Places
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Population exposure (USGS PAGER)
Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.
| Shaking intensity (MMI) | Description | Population exposed |
|---|---|---|
| MMI 3 | weak | 209,603 |
Earthquake Details
-173.0721°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 5.6 earthquake near Hihifo, Tonga?
The magnitude 5.6 earthquake that struck 135 km NE of Hihifo, Tonga on March 22, 2026 at 16:00 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 -14.9521°, -173.0721°, which is 135 km NE of Hihifo, Tonga. The nearest populated place is Nofoali`i (population 2,018). View all earthquakes in Tonga.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.6 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 5.6 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: us6000siia). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, March 22, 2026). M5.6 Earthquake 135 km NE of Hihifo, Tonga — March 22, 2026. Retrieved May 10, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000siia/