The pacific plate is one of the most special and unique tectonic plates on Earth. The reason is is that it has no continents held on it. It is the only major tectonic plate that over 99% of it is oceanic crust. The reason it is not 100% oceanic crust is because there is a little tail of land that we call California, you know," where the sun is hot, but the surfers are oh so cool." It has never sunken, as for it has always been underwater since the planet was born. It has not moved on it's own, but has glided with the other tectonic plates.