GEOLOGY

Detailed explanation-1: -The overridden plate (the slab) sinks at an angle of approximately 25 to 75 degrees to Earth’s surface. This sinking is driven by the temperature difference between the slab and the surrounding asthenosphere, as the colder oceanic lithosphere has, on average, a greater density.

Detailed explanation-2: -Where two tectonic plates converge, if one or both of the plates is oceanic lithosphere, a subduction zone will form. An oceanic plate will sink back into the mantle. Remember, oceanic plates are formed from mantle material at midocean ridges.

Detailed explanation-3: -When these collisions occur, the more dense plate slides below the other, which is a process called subduction. So for oceanic-oceanic boundaries, the more dense oceanic plate sinks below the less dense oceanic plate.

Detailed explanation-4: -As a result, low density owing to hydration reduces subduction rates, back-arc spreading, and slab stagnation on the phase boundary at 660-km depth, whereas low viscosity owing to hydration enhances rapid subduction, trench migration, and slab stagnation.

Detailed explanation-5: -When an oceanic plate converges with a continental plate, the oceanic crust will always subduct under the continental crust; this is because oceanic crust is naturally denser.