Tectonic Plates
Tectonic plates are big sections of the Earth’s crust… it’s actually broken into pieces, and the pieces move. Earthquake! Learn more about the tectonic plates… the reason for mountains, earthquakes, the movement of continents, and more…
http://www.pbs.org/wgbh/aso/tryit/tectonics/
http://www.ucmp.berkeley.edu/geology/tectonics.html
http://www.seismo.unr.edu/ftp/pub/louie/class/100/plate-tectonics.html