Large mountains such as Mount Everest were caused by plates colliding together at a fast rate, however something like the Hawaiian Islands were formed by a hot spot occurring in the middle of the Pacific Plate. While the hot spot itself is fixed the plate is in a constant but slow rate of movement. So, as the plate moved over the hot spot the group of islands known as the Hawaiian Island chain were formed. The largest Island being the most recently active and the smaller islands eroding are due to many years of inactivity as they move away from the hot spot.
