The important movement and, as a consequence, overlap of tectonic plates in the Ring of Fire area is the cause for the concentration of volcanic activity.
When tectonic plates are pushed towards one another (converge), the edge of one plate is often forced beneath the edge of another. This is called subduction. Tectonic plates are made of rock, and when their edge is subducted under another plate, the rock melts into magma. When there is too much magma under the surface of the Earth, it can erupt through a volcano.
