Tectonic Plates

4. _____ is the outer layer of Earth and is known as the crust.
5. The scientist who discovered seafloor spreading.
9. A supercontinent that was present before the continents separated.
10. An area with many cracks in Earth’s surface.
11. Rapid shaking of the Earth’s surface for a period of time.
12. An oceanic plate is a tectonic plate in the ocean.
15. When tectonic plates collide.
17. The largest ridge in the ocean is known as the __________ ______.
18. A ________ is created when two tectonic plates converge and one subducts.
19. The Rocky Mountains are an example of a(n) _______ ________.
20. A tectonic plate on land.

1. Tectonic plates that move apart.
2. When the seafloor moves outward from a certain point.
3. __________ proposed the idea of Pangea.
6. Plates under Earth’s surface that move to cause changes in the land.
7. A hot liquid rock under Earth’s surface.
8. A type of mountain that has magma emerging from the surface.
13. Tectonic plates that slide past each other.
14. When tectonic plates converge and one goes under the other.
16. A type of rock formed by the cooling of lava that is found in oceanic plates.