Unit 4: Plate Tectonics

2. The point beneath Earth's surface where rock breaks under stress and causes an earthquake
7. a small volcano built primarily of pyroclastic material ejected from a single vent
12. A type of fault where the hanging wall slides downward; caused by tension in the crust
13. Point on Earth's surface directly above an earthquake's origin
16. A scale that rates an earthquake's magnitude based on the size of its seismic waves.
19. Movements within Earth's mantle that causes tectonic plates to collide, separate, or slide past each other are called __________ __________.
20. a wide, gently sloping mountain made of layers of lava and formed by quiet eruptions
21. a type of fault where rocks on either side move past each other sideways with little up or down motion
22. extremely deep areas in the ocean that are created by a subducting plate
24. A device that records ground movements caused by seismic waves as they move through Earth
26. a large crater caused by the violent explosion of a volcano that collapses into a depression
28. known for its layers of lava flows and cinders. Has pyroclastic flows.
30. occur under compressional force, rock gets thrust upward

1. the liquid layer of the Earth's core that lies beneath the mantle and surrounds the inner core
3. mountains formed by two continental plates colliding and forcing each other upwards.
4. The theory that the earth's crust is divided into plates that move.
5. An underwater moutain chain where new ocean floor is formed
6. boundary that occurs when two tectonic plates slide past each other.
8. One plate going under another plate
9. A type of seismic wave that moves the ground up and down or side to side (transverse)
10. valley A large valley shaped area of the Earth in which plates of the Earth's crust are moving away from each other, forming a system of cracks.
11. A dense sphere of solid iron and nickel at the center of Earth
14. A type of seismic wave that compresses and expands the ground.
15. a sudden and violent shaking of the ground, sometimes causing great destruction, as a result of plate movement.
17. thicker, less dense, older crust making the continents
18. The layer of hot, solid material between Earth's crust and core.
23. Type of plate boundary where two plates separate from each other.
25. A supercontinent containing all of Earth's land that existed about 225 million years ago.
27. boundary that occurs when two tectonic plates collide into each other.
29. thinner, more dense, younger crust making ocean floor