The major geological relationships of the Tonga Trench (violet) which to the south becomes the Kermadec Trench (violet) at the Osbourn Trough and Louisville Ridge intersection. Blue represents ocean depths of a kilometer or so and brown shades are shallower. Land is shown in dark green and the black line delineates the continent of Zealandia.
The Tonga Trench constitutes the northern half of the Tonga-Kermadec subduction system, which extends 2,550 km (1,580 mi) between New Zealand and Tonga.[1]
The Tonga Trench is an oceanic trench located in the southwestern Pacific Ocean. It is the deepest trench in the Southern hemisphere and the second deepest on Earth after the Mariana Trench. The fastest plate-tectonic velocity on Earth is occurring at this location, as the Pacific plate is being subducted westward in the trench.
