There is how the plate subduction happen, the oceanic crust is denser than continental crust. The different density two of them caused the oceanic crust go down to the continental crust. read more
Plate subduction occurs when two tectonic plates converge and at least one of them is an oceanic plate. Oceanic plates are formed at divergent plate boundaries from dense basaltic magma. This magma originates from the mantle beneath and fills the gap between the spreading plates. read more
Subduction is a geological process that takes place at the boundaries between tectonic plates in which one plate is forced underneath another. Subduction occurs when the massive pressures of entire continental or oceanic tectonic plates collide, over the course of millennia, and one slowly is subsumed underneath the other. read more
Subduction is the driving force behind plate tectonics, and without it, plate tectonics could not occur. Subduction zones dive down into the mantle beneath 55,000 kilometers of convergent plate margins (Lallemand, 1999), almost equal to the cumulative 60,000 kilometers of mid-ocean ridges. read more