The crust of our planet is cracked into seven large and many other smaller slabs of rock called plates, averaging about 50 miles thick. As they move (only inches every year), and depending on the direction of that movement, they collide, forming deep ocean trenches, mountains, volcanoes, and generating earthquakes.
About the Author
John Moen is a cartographer who along with his wife are the orignal founders of worldatlas.com. He and his wife, Chris Woolwine-Moen, produced thousands of award-winning maps that are used all over the world and content that aids students, teachers, travelers and parents with their geography and map questions. Today, it's one of the most popular educational sites on the web.
This page was last updated on November 17, 2015.