Kermadec–Tonga subduction zone

[3] At the northern end of the zone the vector of the Pacific plate collision with the Australian changes to north–south from east–west, to the east of Fiji and south of Samoa.

A number of microplates exist between the two major plates and host various back-arc structures of which the largest are the volcanic Tonga–Kermadec Ridge, the actively spreading Lau Basin and the Havre Trough.

The subduction process seems to be driven primarily by the excess weight of the cold/old oceanic plate entering the hot mantle of the Earth.

With the largest underwater volcano chain, the region surrounding the Kermadec–Tonga subduction zone is one of the most geologically diverse areas in the world.

[7] The Kermadec Sanctuary was proposed in 2015 by the Prime Minister of New Zealand, John Key, at the United Nations in New York, which would create an area off limits to aquaculture, fishing, and mining.

[7] In September 2016, the enactment of the Kermadec Sanctuary was delayed due to failed negotiations over the Māori people's rights.