PLATE TECTONICS

1. Occurs when two rocks are pressed together and one block rides up to overlay the other.
4. The lithosphere is divided into large plates that interact with one another and cause geological activity.
6. Is a current in the mantle that occurs when cooler, denser material sinks and warmer, less dense material rises.
8. Is the point at which two tectonic plates collide.
10. In mid ocean ridges a valley that runs along the centre of the ridge.
14. Mountain ridges run along the seafloor.
15. For earthquakes, a number that represents strength.
19. A devastating catastrophe caused by geological processes
20. is the gravitational and subduction-induced pulling of a tectonic plate.
21. A layer of earth between the crust and outer core, which is divided into upper and lower sections.
22. An instrument that measures and records ground vibration.
23. When new material at mid-ocean ridges pushes older material aside, tectonic plates shift.
24. The process by which magma rises to the surface at mid-ocean ridges and forms new ocean crust.

2. The point on earths surfaces above where an earthquake starts.
3. An opening in earths surface where magma and other materials are released.
5. WAVES The vibration caused by the release of energy during an earthquake.
7. Deep valleys on the seafloor.
9. A ground-shaking release of energy caused by a break in the crust.
11. The belief that the Earth's continents have been in the same place since the Earth's formation.
12. In earth science, the location within earth where an earthquake starts.
13. Two tectonic plates slide horizontally past each other.
16. The process of denser crust of a tectonic plate sliding beneath less dense crust of another plate; occurs at convergent plate boundaries and produces deep sea trenches.
17. Is the separation of two tectonic plates.
18. A large break in a rock.