Tonga Trench

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The Tonga Trench is located in the Pacific Ocean and is 10,882 meters (35,702 ft) deep at its deepest point, known as Horizon Deep.

The trench and its forearc form an active subduction zone between two plates of the lithosphere, the Pacific Plate being subducted below the Tonga Plate at the northeastern corner of the Australian Plate. The Tonga Trench extends north-northeast from the Kermadec Islands north of the North Island of New Zealand. The trench turns west north of the Tonga Plate and becomes a transform fault zone. The convergence is taking place at a rate estimated at approximately 15 centimeters (6 in) per year (by Lonsdale, 1986); however, recent Global Positioning Satellite measurements indicate in places a convergence of 24 centimeters (10 in) per year across the northern Tonga Trench, which is the fastest plate velocity recorded on the planet (Bevis et al., 1995). Such oceanic trenches are important sites for the formation of what will become continental crust and for recycling of material back into the mantle. Along the Tonga Trench mantle-derived melts are transferred to the island arc systems, and abyssal oceanic sediments and fragments of oceanic crust are collected.

The trench is the last resting place of the Radioisotope thermoelectric generator from the aborted Apollo 13 mission.

The Kermadec Trench, to the south, is basically an extension of the Tonga Trench.

[edit] References

Wriget, Dawn J., et. al., 2001, Bathymetry of the Tonga Trench and Forearc: A Map Series, as published in Marine Geophysical Researches, 2000. PDF version
Bird, P., An updated digital model of plate boundaries, Geochem. Geophys. Geosyst., 4(3), 1027, doi:10.1029/2001GC000252, 2003.[1] also available as a PDF file (13 mb) [2]