Plate boundaries are where the action is. A large fraction of all earthquakes, volcanic eruptions, and mountain building occurs at plate boundaries. It is also where most of the people on Earth live.

Plate tectonics is the theory used to explain the structure of the Earth’s crust and many of the associated phenomenon. The rigid lithosphere is split into 15 major plates that slowly move on top of ...

It’s right there in the name: “plate tectonics.” Geology’s organizing theory hinges on plates—thin, interlocking pieces of Earth’s rocky skin. Plates’ movements explain earthquakes, volcanoes, ...