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Subduction is the driving force behind plate tectonics, and without it, plate tectonics could not occur. [12] Oceanic subduction zones are located along 55,000 km (34,000 mi) of convergent plate margins, [13] almost equal to the cumulative plate formation rate 60,000 km (37,000 mi) of mid-ocean ridges. [14]
Subduction of the Nazca plate beneath the South American plate to form the Andes. Subduction of the Pacific plate beneath the Australian plate and Tonga plate, forming the complex New Zealand to New Guinea subduction/transform boundaries. Collision of the Eurasian plate and the African plate formed the Pontic Mountains in Turkey.
Slab pull is a geophysical mechanism whereby the cooling and subsequent densifying of a subducting tectonic plate produces a downward force along the rest of the plate. In 1975 Forsyth and Uyeda used the inverse theory method to show that, of the many forces likely to be driving plate motion, slab pull was the strongest. [1]
Some troughs look similar to oceanic trenches but possess other tectonic structures. One example is the Lesser Antilles Trough, which is the forearc basin of the Lesser Antilles subduction zone. [8] Also not a trench is the New Caledonia trough, which is an extensional sedimentary basin related to the Tonga-Kermadec subduction zone. [9]
A volcanic arc is part of an arc-trench complex, which is the part of a subduction zone that is visible at the Earth's surface. A subduction zone is where a tectonic plate composed of relatively thin, dense oceanic lithosphere sinks into the Earth's mantle beneath a less dense overriding plate. The overriding plate may be either another oceanic ...
This subduction zone was responsible for the 2004 Indian Ocean earthquake and tsunami. [15] In parts of the megathrust south of Java , referred to as the Java Trench , for the western part, M w 8.9 is possible, while in the eastern Java segment, M w 8.8 is possible, while if both were to rupture at the same time, the magnitude would be M w 9.1.
Multiple earthquakes occur along this subduction boundary with the seismic hypocenters located at increasing depth under the island arc: these quakes define the Benioff zone. [ 10 ] [ 11 ] Island arcs can be formed in intra-oceanic settings, or from the fragments of continental crust that have migrated away from an adjacent continental land ...
The role of water and other volatiles in the melting of existing crustal rock in the wedge above a subduction zone is a most important part of the cycle. Along with water, the presence of carbon dioxide and other carbon compounds from abundant marine limestone within the sediments atop the down going slab is another source of melt inducing ...