The Pacific Coast is tiptoeing around not one but two of the largest seismic triggers of the region’s modern history.

This area, called the Cascadia Subduction Zone, hosts a megathrust fault, a place where tectonic plates move against each other in a highly dangerous way. The plates can periodically lock up and ...

According to plate tectonics theory, Earth's outer shell is divided into multiple plates that slowly glide ... For more animations from Scotese about tectonic plate motions — past and present ...