How does hot spot make a chain of volcanoes?

Answer 1

A hot spot, unlike other forms of volcanism that rely on plate subduction, is due to rising heat from a specific location in the mantle which is very localized, not broadly regionalized. The Hawaiian Islands are a great example of the resultant landforms created by a hot spot that exists under oceanic crust. While the crust moves over the hot spot due to plate tectonics, volcanic mountains build up on the ocean floor, eventually breaching the surface of the water. As the crust moves away, the existing volcanic mountains become inactive and are replaced with newer volcanic mountains, the older ones slowly eroding below the surface of the ocean.

Answer 2

If I use the example of Hawaii, a chain of islands all produced by volcanic activity from a hotpot.

Hot spots form as a magma plume erupts through the surface and produces a fissure vent on the ocean floor. The basaltic magma from this vent frequently erupts and over time builds up to form an island, built around one or more volcanoes.

As the tectonic plates gradually move the island that has built up is pushed away from the hotpot, while the hotspot remains in the same place as it is charged from within the mantle.

So it is the movement of the Earths crust due to the movement of the tectonic plates that creates chain island/ volcanoes as lava continues to erupt from the vent creating more and more islands. This island/ volcano building process is still continuing today as the Mauna Loa volcano on Hawaii is still erupting today and continues to form the landscape.