Earth Science

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Across
  1. 3. number that rates the strength of an earthquake
  2. 5. precess where new material at a ridge or rift, pushed older material aside and tectonic plates move away from the ridge
  3. 8. layer formed when early Earth cooled, the lighter elements, such as silicon and oxygen, separated from the molten material and floated to the top
  4. 11. process of Earth's magnetic fields moving from time to time and completely reversing its direction
  5. 12. sudden, ground shaking release of built-up energy at or under Earth's surface
  6. 15. process where convection currents cause more magma to rise, the new magma forces apart the hardened material and continuously pushes older rock aside
  7. 18. usually found along subduction zones where there are convergent plate boundaries
  8. 19. a long chain of volcanic islands
  9. 20. an area where molten rock rises to Earth's surface (weak spot)
  10. 21. not found at plate boundaries bit instead form over hotspots
  11. 22. one of the driving forces behind Earth's movement
  12. 26. cause ground to compress and stretch in direction of wave
  13. 27. refers to extent of ancient glaciers and to rock markings left behind
  14. 28. study of earthquakes and seismic waves
  15. 29. location inside Earth where an earthquake starts
  16. 31. where magma cools and hardens when it breaks through Earth's surface
  17. 34. plates that are spreading apart
  18. 35. study of magnetic properties of ancient rocks
  19. 38. Earth's thickest layer; solid
  20. 39. faults at a transform plate
  21. 40. when the age of a tectonic plate subduct deep into the mantle and pulls the rest pf the plate along with it
  22. 41. record of ground motion produced by seismometers
  23. 42. reading centre that occurs on land
  24. 43. lies at Earth's centre; solid iron with some nickel
Down
  1. 1. devices that measure amount of ground movement caused by and earthquake
  2. 2. vibrations produced by energy released from earthquakes
  3. 4. a long chain of volcanoes
  4. 6. breaks in rock layers due to movement on either side
  5. 7. a deep underwater valley
  6. 9. the action of one plate being pushed under another
  7. 10. a pattern of stripes in the direction that iron-containing minerals pointed on the sea floor; repeated on both side of the Mid-Atlantic Ridge
  8. 13. area of subduction
  9. 14. layer below mantle; liquid with mixture of iron and nickel
  10. 16. occur when magma erupts through cracks in the lithosphere where there are diverging plate boundaries
  11. 17. cause ground to compress and stretch in right angles to the direction of the waves
  12. 23. plates that collide
  13. 24. large, movable slabs of rock that Earth is broken into
  14. 25. openings in Earth's surface, that, when active, spew out gases, chunks of rock, and melted rock
  15. 30. region where tectonic plates are in contact
  16. 32. point on Earth's surface directly above the focus
  17. 33. pertly molten layer in the upper mantle
  18. 36. made up of crust, and uppermost mantle; formed by tectonic plates
  19. 37. molten rock from beneath Earth's surface