Plate Tectonics

2. Earthquakes occur along _____ _____, cracks in Earth's crust where tectonic plates meet.
3. As the plates continue to _____, mountains will get taller and taller.
6. Earths' crust and upper part of the mantle are broken into large pieces called _____ _____.
7. Magma that has cooled on the surface is known as _____ rock.
9. _____ rocks are formed by magma from the molten interior of the Earth.
10. Most limestone is obtained by _____, where the rock is blasted out of the ground in huge pits.
12. The theory of continental drift was proposed by the German scientist _____.
13. Scientists describe the intensity of an earthquake using the _____ _____.
15. Earth's _____ is the rigid outer layer that is made up of the crust and the part of the mantle just below it.
18. An _____ is the sudden movement of Earth's crust.
19. _____ trapped in the rocks in this plate gets squeezed out. This causes some of the rocks to melt. The melted rock, or magma, is lighter than the surrounding rock and rises up.
20. What sedimentary rock is a valuable resource from the Earth's crust?
21. _____ are vents, or openings in Earth's crust, that release ash, gases and steam, and hot liquid rock called lava.

1. The deposited rocks build up in layers, called sediments. This process is called _____.
4. _____ _____ cause the tectonic plates to move.
5. When enough _____ builds up in the magma chamber, it forces its way up to the surface and erupts, often causing volcanic eruptions.
8. In the ocean, volcanoes erupt along cracks that are opened in the ocean floor by the spreading of two plates called a _____ _____ _____.
11. _____ is a large circle of explosive volcanoes around the Pacific Ocean.
14. _____form where two continental plates collide.
16. Innermost layer of Earth.
17. What was the supercontinent called?