GEOLOGY

Detailed explanation-1: -A volcanic arc is a chain of volcanoes, hundreds to thousands of miles long, that forms above a subduction zone. An island volcanic arc forms in an ocean basin via ocean-ocean subduction. The Aleutian Islands off the coast of Alaska and the Lesser Antilles south of Puerto Rico are examples.

Detailed explanation-2: -Beneath the ocean, massive tectonic plates converge and grind against one another, which drives one below the other.

Detailed explanation-3: -The formation of island arcs is dependent on plate tectonics. The majority of island arcs are located on subduction boundaries between two plates with oceanic lithosphere.

Detailed explanation-4: -When two oceanic plates collide against each other, the older and therefore heavier of the two subducts beneath the other, initiating volcanic activity in a manner similar to that which occurs at an oceanic-continental convergent plate boundary and forming a volcanic island arc.