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.
Subduction often results in spectacular natural geographic phenomena. Geological subduction is exemplified by the Himalayan Mountains, the earthquakes of the American Pacific coast and the volcanic activity that gave rise to the island of Japan. Subduction is one of the most immense physical processes on Earth, shaping the face of the Earth itself.