2. Divergent: two plate are moving away from each other

3. This occurs at mid-ocean ridges Features formed include ridges and rift valleys as well as the formation of new oceans. Divergent: two plates are moving away from each other

4. Convergent: two plates come together Three kinds of collisions: 2 continental plates collide an oceanic and a continental plate collide 2 oceanic plates collide

5. Convergent: two plates come together 2 continental plates collide

6. Convergent: two plates come together 2 continental plates collide Features include: folded mountain range

8. Convergent: two plates come together an oceanic and a continental plate collide

9. Convergent: two plates come together an oceanic and a continental plate collide Features include: trench, volcanic arc (mountain range)

10. Convergent: two plates come together Features include: trench, island arc 2 oceanic plates collide

12. Oceanic-oceanic convergence

13. Transform: two plates slide past each other

14. Features include: faults and fracture zones

15. Movement of material caused by differences in temperature

16. The temperature of the lower mantle is higher than the temperature of the upper mantle SO, cooler mantle sinks, heats up, and rises. Upper Mantle 870 0 C Lower Mantle 2200 0 C The rising/sinking cycle of mantle makes a circular motion that moves the plates!

17. The constant motion of the Mantle moves the Crust around!

18. But the convection cells get help with ridge push and slab pull.

19. New parts of a plate rise because they are warm and the plate is thin. As hot magma rises to the surface at spreading ridges and forms new crust, the new crust pushes the rest of a plate out of its way. This is called ridge push. At mid-ocean ridges the oceanic lithosphere is higher than where it sinks into the asthenosphere so gravity helps the lithosphere slide down

20. Old parts of a plate are likely to sink down into the mantle at subduction zones because they are colder and thicker than the warm mantle material underneath them. This is called slab pull. Oceanic lithosphere is denser than the asthenosphere so the edges of oceanic lithosphere sink and pull the rest of the plate with it as it sinks.

21. The three most commonly used space-geodetic techniques -- very long baseline interferometry (VLBI), satellite laser ranging (SLR), and the Global Positioning System (GPS) -- are based on technologies developed for military and aerospace research, notably radio astronomy and satellite tracking. Among the three techniques, to date the GPS has been the most useful for studying the Earth's crustal movements. Twenty-one satellites are currently in orbit 20,000 km above the Earth as part of the NavStar system of the U.S. Department of Defense. These satellites continuously transmit radio signals back to Earth