Answer:
A tectonic plate is moving over a mantle plume, which burns through the plate to create a chain of volcanoes.
Step-by-step explanation:
For a chain of volcanic islands to form, it is necessary for the tectonic plates to move on top of a mantle plume, thus creating a "cord" of islands, forming the chain of volcanic islands.
A plume mantle is also called a hot spot and is formed by a geological thermal aanomalia, which pulls the magma from the deepest layers to the surface.