Plate Tectonics

5. The large, relatively stationary area of volcanic activity away from plate boundaries
6. A type of plate boundary where two plates move toward each other
7. The circulation in the mantle driven by heat differences, believed to move the plates
9. The largest type of landmass, combining all or most continents
10. The name given to the single massive landmass 200 million years ago
11. A measure used to quantify the magnitude of an earthquake
13. A large, circular volcanic depression capable of massive eruptions
16. A vent in the Earth's crust that releases molten rock, ash, and gases
17. A fracture or zone of weakness in Earth's crust
18. A type of plate boundary where two plates are moving away from each other
19. Molten rock that has erupted onto Earth's surface
21. The ground shaking caused by a rapid release of energy in the Earth's crust

1. The process where one oceanic plate sinks beneath another plate
2. The layer of Earth's crust that forms the continents
3. A seismic vibration produced by the sudden release of energy during rock rupture
4. Boundary where plates slide horizontally past one another
8. The theory describing the slow movement of continents over geologic time
12. The large, rigid sections of Earth's lithosphere that move relative to one another
14. The dense, heavy plate type that makes up the ocean floor
15. The large depression in the Earth's surface that holds ocean water
20. Molten rock found beneath the Earth's surface