Plate Tectonics

3. The outermost part of Earth that is mostly made up of granite.
5. Steep-walled depression around a volcano's vent.
6. The point of Earth's surface directly above an earthquake's focus.
8. A device used by scientists to record primary, secondary, surface waves from earthquakes.
9. The theory that explains how and why continents move
12. Rigid, outermost layer of the earth that is about 100km thick.
13. A common rock type within the oceanic crust.
16. The large opening formed when the top of a volcano collapses.
17. A scientist who studies earthquakes and seismic waves.
19. Surface along which rocks break and move?
20. There are ___ primary plates that form Earth's crust.

1. The name Alfred Wegener gave to the super-continent.
2. A geological process in which one edge of one crustal plate is forced below the edge of another.
4. A common rock type found within the continental crust.
7. A sudden movement along the boundary of a tectonic plate is called?
10. Tectonic plates float on the _?
11. Seismic sea wave
14. What lies directly beneath the crust?
15. Opening in the earth's surface that often forms a mountain when layers of lava and volcanic ash erupt and build up.
18. Measure of the energy released by an earthquake.