plate tectonics

2. A vent in the Earth's surface through which molten rock (lava) and gases are expelled.
4. Plate Boundary Where two plates move apart, creating new crust.
6. Spreading: The process where new oceanic crust is created at divergent boundaries.
8. The layer of the Earth between the crust and the core.
11. The outermost solid layer of the Earth.
12. The soft, plastic layer of the upper mantle beneath the lithosphere.
15. Drift The theory that continents have moved over time.
16. A shaking of the ground caused by the sudden movement of tectonic plates.
18. Plates Large, moving pieces of the Earth's lithosphere
20. Zone A convergent boundary where one plate slides under another.

1. The supercontinent that existed millions of years ago.
3. Fault: A boundary where plates slide past each other.
5. Waves Waves of energy that travel through the Earth during an earthquake.
7. The rigid outer layer of the Earth, including the crust and upper mantle.
9. A sudden shaking of the Earth's crust.
10. A fracture in the Earth's crust where movement has occurred.
13. Waves Energy released during an earthquake.
14. Plate Boundary Where two plates collide.
17. Spot A region of high volcanic activity
19. The innermost part of the Earth, consisting of a solid inner core and a molten outer core.