Shallow M5.6 earthquake hits offshore Tonga

An earthquake registering M5.6 was recorded at 16:00 UTC on March 22, 2026, approximately 136 km (85 miles) northeast of Hihifo, Tonga. The event occurred at a shallow depth of 10.0 km (6.2 miles), based on the reviewed data from USGS.

The epicenter was positioned at 15.0°S, 173.0°W, placing it offshore in the northern waters of Tonga, distant from major populated areas but within a seismically active region of the Pacific Ocean.

Given the offshore location, the area is characterized by maritime shipping routes and minimal critical infrastructure, primarily related to fisheries and local sea transport. Major ports or airports are not in the immediate vicinity, with Hihifo and other islands forming the closest habitations.

There is no tsunami threat associated with this earthquake, based on its location and available data.

USGS issued a green alert for this event, indicating a low likelihood of casualties or damage. The maximum estimated intensity was IV, and the significance index is 482 (on a scale that runs through 1 000), reflecting the moderate magnitude and offshore location.

This area of Tonga is situated along the Tonga-Kermadec subduction zone, a segment of the Pacific “Ring of Fire” known for frequent seismic activity as the Pacific Plate subducts beneath the Indo-Australian Plate.

This information was last updated at 16:24 UTC on March 22, 2026.