Answer:
Subduction of one plate under another.
Step-by-step explanation:
Most of the volcanic activity that occurs in the ring of fire is a result of Subduction of one plate under another. Subduction zones produce volcanic arcs. The Subduction zones mark the collision between the two tectonic plates. These plates move slowly across the earth's surface over million of years. These Subduction zones occur around the border of the pacific ocean.