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11. What is the difference between the Earth’s lithosphere and asthenosphere?
* lithosphere is more-rigid; asthenosphere is more-plastic/easily deformed.
* It is on top of the asthenosphere.
12. What does the oceanic crust consist of and how thick is it?
* basalt, about 7 km thick
13. What does the continental crust consist of and how thick is it?
 “granite” composition (whole range of continental rocks, especially granite, gneiss,
schist) 30 to 60 or 70 km thick
14. What are the main types of lithospheric plate boundaries, in terms of relative motions?
Provide a real example of each (by name or location)
* convergent (continent – ocean plate collision): Cascadia subduction zone (Pacific
Ocean floor against North America)
* convergent (continent- continent collision): Himalayas
* divergent (rift or spreading, or extension): mid-oceanic ridge
* transform (lateral motion): San Andreas Fault
15. Along which type(s) of lithospheric plate boundary are basalt-flow eruptions abundant?
Provide a real example (name or location).
* spreading (Iceland/oceanic ridge)
16. In what tectonic environment that is not at a plate boundary, are major volcanoes
found? Identify one of these in an ocean basin and one on a continent.
* hotspots or mantle plumes
* in ocean basin: Hawaii;
* on continent: Yellowstone
17. List the three main tectonic environments for large earthquakes in western North
America and name a specific example of each.
Tectonic environment
Name or specific location
* subduction zone
Pacific Coast trench (Cascadia trench)
* spreading zone
Basin and Range
* transform fault
San Andreas Fault
18. In what tectonic environment that is not at a plate boundary are major volcanoes found?
Identify one of these in an ocean basin and one on a continent.
* mantle plume or hotspot
* An example in an ocean basin is Mauna Loa, Hawaii
* An example on continent is Yellowstone.
19. The lithosphere is composed of what two layers?
* Crust and upper mantle
20. With which type or types of boundary are active volcanoes generally associated?
* divergent (or spreading), convergent (or subduction)