The earth is covered with rigid plates that move across a weak layer in the mantle.  What happens when large chunks of the earth slide past one another?   Here's a hint.  Here's what they do to famous geologists.
Now...take a look at this page from the US Geological Survey (look at the map at the bottom of the page);  then think about these questions.

1. Can you tell where the plate margins are located? (go to Columbia University for the answer)
2. What is another cause of these earthquakes (here's a hint).
3. are 1 & 2 two related? (stumped?)

Now that we've seen what tectonics does on the surface, what about deep down in the earth?

Rocks deep in the earth are hotter and under pressure; here, the weak rocks bend while strong or brittle rocks break.  If two plates collide into one another, compression creates folds and faults (see this good lecture page).  All of the relief that we see in the Appalachian Mountains (or here) of Rockbridge County was created by folds and faults at great depth. They have subsequently been exposed by erosion.

The movement of plates is what drives the "rock cycle" and continually recreates new materials at the surface of the earth.  But this cycle depends on erosion, too, so go the the rivers and erosion part of your course.

Here's a full course on Plate Tectonics, if you need more info.

created by Dave Harbor