Across
- 3. a deep underwater valley
- 5. is the action of one plate pushing below the other
- 6. waves- a body wave that travels about 6 km through earths crust
- 8. a seismometer produces a record of ground motion
- 10. plate boundary- occurs where tectonic plates collide
- 11. ridge- ridge lay right along the middle of the ocean floor
- 12. drift theory- states that the continents have not always been in their present locations but "drifted" there over a million years
- 13. refers both to the extent of ancient glaciers and to the rock makings they have left behind
- 15. fault- a fault that occurs at a transform plate boundary
Down
- 1. is a sudden, ground shaking release of built-up energy at or under Earths surface
- 2. plates- earths broken into large, movable slabs of rock
- 4. pull- as the edge of a tectonic plate sub ducts deep into the mantle, it pulls the rest of the plate with it
- 6. is the study of the magnetic properties of the ancient rocks
- 7. reversal- is the direction that can completely reverse
- 9. a partly molten layer in the upper mantle
- 14. belt- a long chain of volcanoes
- 16. molten rock from beneath the earths surface