Flexi Says: Two oceanic plates may collide. In this case, the older plate is denser. This plate subducts beneath the younger plate. As the subducting plate is pushed deeper into the mantle, it melts. The magma this creates rises and erupts. This forms a line of volcanoes, known as an island arc. Japan, Indonesia, the Philippine Islands, and the Aleutian Islands of Alaska are examples of island arcs.
