In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate and sinks into the mantle as the plates converge.
A subduction zone is the biggest smash-up on Earth, marking the collision between two of the planet's tectonic plates, the pieces of crust that slowly move across the surface over millions of years.
In plate tectonics, a divergent boundary or divergent plate boundary (also known as a constructive boundary or an extensional boundary) is a linear feature that exists between two tectonic plates that are moving away from each other.
Divergent plate boundaries are locations where plates are moving away from one another.
A subduction zone is formed at a convergent plate boundary when one or both of the tectonic plates is composed of oceanic crust. The denser plate, made of oceanic crust, is subducted underneath the less dense plate, which can be either continental or oceanic crust.
Convergent plate boundaries are locations where lithospheric plates are moving towards one another.