How does the movement of the mantle affect human societies?

The movement of the mantle propels the tectonic plates. The location tectonic plates have allowed modern societies to exist in their present environments. The movement of the tectonic plates pushes oceanic crust into the mantle where a portion later rises as volcanic magma. These result in volcanic explosions that have at times helped human societies by providing fertile soil and at other times nearly wiped out human populations by the effects of the volcanic eruption.