Subduction Zone

A subduction zone is the convergent boundary where one plate, usually older, denser oceanic lithosphere, descends beneath another into the mantle, marked at the surface by a deep ocean trench and inland by a volcanic arc. The descending slab generates the world’s largest earthquakes (including the great tsunami-producing megathrust events) and recycles crust and water into the mantle. Slab pull is the dominant force driving plate motion.