subduktiovyöhykset

Subduktiovyöhykkeet, also known as subduction zones, are geological areas where one tectonic plate slides beneath another and sinks into the Earth's mantle. This process is a fundamental mechanism of plate tectonics and is responsible for many of the Earth's most dramatic geological features and phenomena.

When an oceanic plate converges with another plate, either oceanic or continental, subduction typically occurs. Because oceanic crust is denser than continental crust, an oceanic plate will usually subduct beneath a continental plate. If two oceanic plates collide, the older, colder, and therefore denser plate will subduct beneath the younger, warmer one. As the denser plate descends into the hotter mantle, it heats up and releases water. This water lowers the melting point of the surrounding mantle rock, causing it to melt and form magma.

This magma rises to the surface, erupting to form volcanic arcs on the overriding plate. These volcanic arcs are often located parallel to the subduction zone. The friction and stress generated by the movement of the plates along the subduction zone also lead to powerful earthquakes, which can be shallow or deep, depending on the depth of the subducting plate. The Mariana Trench, the deepest part of the world's oceans, is a prime example of a subduction zone where the Pacific Plate is subducting beneath the Mariana Plate.