1. Intro to Earth- Geosphere SJCHS

2. Geosphere Geosphere: Land on surface and interior of Earth

3. Geosphere Lithosphere: cool, rigid shell (made of rocks) Asthenosphere: part of mantle made of malleable rock Mesosphere: part of mantle made of solid rock

4. Geosphere Outer Core: Molten iron and nickel Causes Earth ’ s Magnetic field Inner Core: Solid iron and nickel

5. Plate Tectonics Theory of Plate Tectonics: Earth ’ s lithosphere is fragmented into a dozen plates that are moving

6. Plate Tectonics-History Early 1900s: Alfred Wegener proposes continental drift Continents were once one giant land mass (Pangaea) that had separated over time

7. Plate Tectonics-Evidence Continents look like a puzzle with pieces that fit together The same fossils were found on continents separated by oceans

8. Plate Tectonics-Evidence

9. Plate Boundaries Divergent Boundary: Plates are moving apart, forms new crust

10. Plate Boundaries Rifts: Surface cracking, can form oceans Mid ocean ridges: Newly formed (200 million years old) underwater mountain chains

11. Plate Boundaries

12. Convergent Boundaries: One plate sinks under another (subducts); forms trenches, mountains

13. Plate Boundaries

15. Transform-fault boundaries: 2 Plates sliding horizontally past each other

16. Plate Boundaries Active volcanoes and earthquakes tend to occur around most plate boundaries

20. Cause of Plate Tectonics Sea floor spreading or ridge pull: New lithosphere forms at mid ocean ridges (underwater mountains) causing plates to move

21. Cause of Plate Tectonics Convection in mantle causes motion of plates

22. Cause of Plate Tectonics Slab pull: As a plate subducts, it pulls the rest of the plate with it due to gravity

23. Volcano Volcano: A structure made of a combination of cooled molten rock and/or dust/rocks Fueled by magma that enters the crust from the mantle when a plate subducts

24. Volcano Lava: Molten rock Pyroclastic flow: A combination of hot ash, dust, and gases that travel at high speeds from eruption

25. Lava Basaltic: Thin lava, dark in color, high in temperature, flows quickly Rhyolitic: Thicker lava, light in color, lower temperature, flows slowly Andesitic: In-between other 2 types

26. Volcano Quiet eruptions: Lava only Explosive eruptions: Pyroclastic material and lava

27. Hot Spots http://www.pbs.org/wnet/nature/lessons/ feeling-hot-hot-hot/video-segments- violent-hawaii/1533/

28. Earthquake Earthquake: When a break between rocks (fault) moves causing ground vibrations (seismic waves)

29. Earthquake Body Waves: Travel through Earth P (primary) waves Fastest (6 km/s) Compressional waves: Cause change in volume and density of material

30. Earthquake S (secondary) waves Half speed of P waves Shear waves: Cause change in shape of material

31. Earthquake Surface waves: travel on surface of Earth half speed of S waves Can move ground vertically or horizontally

32. Earth Interior Can use seismic waves to determine composition of crust, mantle, core S waves only travel through solids P waves travel through solids and liquids P waves travel faster through solids, slower in liquids

33. Earthquake Earthquakes cause damage through shaking and liquefaction Liquefaction: Soil and sediment behaves like a liquid and cannot support structures

34. Earthquake Tsunami or Seismic Sea Wave A fault in the ocean slips or a large underwater land slide occurs Creates a fast moving wave (500-1000 km/hr) As waves reach shore, velocity decreases but height increases

35. http://www.youtube.com/watch?v=mFsdl7 _9l4I http://www.youtube.com/watch?v=mjOmv 4HXqCs http://www.youtube.com/watch?v=naQZ0 PR3S6w