Plate tectonics

4. A device used to record earthquake waves.
5. A boundary in which two plates move toward each other, causing one of the slabs of the lithosphere to subduct beneath an overriding plate.
8. The rigid outer part of the earth, consisting of the crust and upper mantle.
11. A sudden and violent shaking of the ground, sometimes causing great destruction, as a result of movements within the earth's crust or volcanic action
14. The thick part of the Earth’s crust, not located under the ocean.
17. A region where the crustal plates are moving apart.
19. A large natural elevation of the earth's surface rising abruptly from the surrounding level; a large steep hill.
20. Valley A large elongated depression with steep walls formed by the downward displacement of a block of the earth's surface between nearly parallel faults or fault systems.

1. The thin part of the Earth’s crust located under the oceans.
2. Soft, weak upper portion of the mantle where the lithospheric plates float and move around.
3. A depression in the seafloor produced by subduction process.
6. A break in a rock along which movement has occurred.
7. The sideways and downward movement of the edge of a plate of the earth's crust into the mantle beneath another plate.
9. Spot A concentration of heat in the mantle capable of creating magma.
10. tectonic A theory which suggests that Earth’s crust is made up of plates that interact in various ways, thus producing earthquakes, mountains, volcanoes, and other geologic features.
12. Rigid sections of the lithosphere that move as a unit.
13. A mountain or hill, typically conical, having a crater or vent through which lava, rock fragments, hot vapor, and gas are being or have been erupted from the earth's crust.
15. A boundary produced when two plates slide past to each other.
16. The outer portion of the Earth.
18. The science that studies Earth.