Across
- 2. A device that uses sound waves to measure the depth of the seafloor.
- 4. A field produced by a magnetic object that exerts a force on other magnetic materials or moving electrical charges.
- 6. Primary waves; arrive first at a seismograph
- 8. A line of volcanoes on a continent resulting from subduction beneath the continent.
- 9. The cycle in which the continents join into one supercontinent and then move apart to join together at the other side of the planet as another supercontinent.
- 12. The innermost, densest layer of a celestial body
- 13. An instrument that measures the magnetic field intensity.
- 14. A magnetic mineral that takes on Earth's magnetic polarity as it crystallizes.
- 16. The layer of solid, brittle rock that makes up the Earth's surface; the crust and the uppermost mantle.
- 19. The movement of material due to differences in temperature.
- 20. A deep gash in the seafloor; the deepest places on Earth.
- 22. The rocky outer layer of the Earth's surface.
- 23. Secondary waves; arrive second at a seismograph.
- 26. A circular pattern of warm material rising and cool material sinking.
- 30. A divergent plate boundary that breaks up a continent.
- 31. An enormous body of granitic rock.
- 33. The path on the globe showing where the magnetic pole appeared to move over time.
- 34. Fragments of planetary bodies such as moons, planets, asteroids, and comets that strike Earth.
- 35. Very flat areas that make up most of the ocean floor
- 36. A location where two lithospheric plates come together.
- 37. The area where two lithospheric plates come together and one sinks beneath the other.
- 39. A location where two lithospheric plates spread apart.
- 40. The crust that makes up the continents; thicker and less dense than oceanic crust.
Down
- 1. The crust that underlies the oceans; thinner and denser than continental crust.
- 3. A location where two plates come together.
- 5. The theory that the Earth's surface is divided into lithospheric plates that move on the planet's surface.
- 7. The type of plate boundary where two plates slide past one another.
- 10. Also called earthquake waves. Seismic waves transport the energy released during an earthquake. Seismic waves give scientists information on Earth's interior.
- 11. An earthquake fault; one plate slides past another.
- 15. The early 20th century hypothesis that the continents move about on Earth's surface.
- 17. The point on the Earth's surface directly above the focus of the earthquake.
- 18. The process in which energy moves from a location of higher temperature to a location of lower temperature as heat.
- 21. The direction of the Earth's magnetic field.
- 24. The mechanism for moving continents. The formation of new seafloor at spreading ridges pushes lithospheric plates on the Earth's surface.
- 25. A slab of Earth's lithosphere that can move around on the planet's surface.
- 27. The sinking of one lithospheric plate beneath another.
- 28. A line of ocean island volcanoes resulting from subduction beneath oceanic lithosphere.
- 29. Geologic activity that takes place away from plate boundaries.
- 32. A plume of hot material that rises through the mantle and can cause volcanoes.
- 38. The middle layer of the Earth; made of hot rock that circulates by convection.