Across
- 7. a measure of the energy released by on earthquake
- 9. cone-shaped hill or mountain formed when hot magma, solids, and gas erupt onto Earth’s surface through a vent
- 11. instrument used to record seismic waves
- 12. point deep in side Earth where energy is released, causing an earthquake
- 15. drift Wegener's hypothesis that all continents were once connected
- 17. point on Earth’s surface directly above an earthquake’s focus
- 19. spot hot, molten rock material that has been forced upward from deep inside Earth, which may cause magma to break through Earth’s mantle and crust and may form volcanoes
- 20. spreading Hess's theory that new seafloor in formed when magma is forced upward toward the surface at a mid-ocean ridge
Down
- 1. movement of the ground that occurs when rocks inside Earth pass their elastic limit
- 2. safe describes the ability of structures to stand up against the vibrations caused by an earthquake
- 3. Large, ancient landmass that was composed of all the continents
- 4. volcano steep-sided volcano formed from alternating layers of violent eruptions of tephra and quieter eruptions of lava
- 5. cone volcano relatively small volcano formed by moderate to explosive eruptions of tephra
- 6. rigid layer of Earth about 100km thick, made of the crust and a part of the upper mantle
- 8. fracture that occurs when rocks break and that results in relative movement of opposing sides
- 10. molten rock flowing onto Earth’s surface
- 13. current, current in Earth's mantle
- 14. a large section of Earth's oceanic or continental crust about 100km thick, made of the upper mantle
- 16. powerful seismic sea wave the begins over an ocean-floor earthquake
- 18. long crack, fissure, or though that forms between tectonic plates moving apart at plate boundaries
- 20. volcano large, broad volcano with gently sloping sides that is formed by the buildup of basaltic layers