• Anton Magus

    The Earth’s crust is criss-crossed by fault-lines and not uniformly thick everywhere. Where the continental plates join there are major fault-lines. Where the crust is thin and the continental plates join, the molten magma can reach the surface and push up into a volcano. If it pushes right to the surface, then pressure builds up and the volcano erupts. Iceland is on a joint in the continental plates which runs right down the mid-Atlantic Ocean. That’s why Iceland has volcanoes.