1. Chapter 14

2. 1. Which type of body wave travels the fastest?
S wave
P wave
They travel at the same speed.

3. 2. Which body wave travels through solids and liquids?
S wave
P wave
They both do.

4. 3. Which of the following phenomena led to the conclusion that the outer core is liquid?
P-wave shadow zone
S-wave shadow zone
Earth’s gravitational field
wave refraction

5. 4. When a P wave encounters a denser rock layer it:
travels faster.
travels more slowly.
travels at the same speed.
bounces upward and does not transmit into the underlying denser layer.

6. 5. Density changes between Earth’s layers cause waves to be ____, and waves are ____ by layer boundaries.
reflected; refracted
refacted; reflected
Both types of change primarily cause reflection.
Both types of change primarily cause refraction.

7. 6. The Mohorovičić discontinuity separates the:
crust and mantle.
inner and outer core.
mantle and outer core.
lithosphere and asthenosphere.

8. 7. Why can’t continental crust be subducted?
It is too buoyant and can’t sink into the asthenosphere.
Continental crust is denser than the asthenosphere.
This is a bogus question. Continental crust can be subducted, just like oceanic crust.

9. 8. The lithosphere includes parts of which compositional layer(s)?
crust
crust and mantle
mantle
mantle and core
core

10. 9. The asthenosphere includes parts of which compositional layer(s)?
crust
crust and mantle
mantle
mantle and core
core

11. 10. From where are mantle plumes sourced?
outer core
inner core
upper mantle
core-mantle boundary

12. 11. The most effective mode of transport of heat from Earth’s interior to surface is:
conduction of the crust.
convection of the mantle.
convection of the inner core.
convection of the crust.

13. 12. Earth does not cool and completely solidify because ______.
increasing pressure continues to heat Earth
the crust insulates Earth from space
convection of the mantle maintains Earth’s heat
decay of radioactive elements produces sufficient heat to maintain higher temperatures

14. 13. The increase in temperature from Earth’s surface to the core is called the:
hydrotherm.
heliotherm.
geotherm.
endotherm.

15. 14. The center of Earth is probably:
1000–1500 degrees.
2500–3000 degrees.
3500–4000 degrees.
5000–7000 degrees.

16. 15. Scientists use seismic tomography to determine:
the concentration of faulting in the mantle.
differences in mantle chemistry.
temperature differences in the mantle.
None of the above.

17. 16. True or False: Based on seismic tomography data, the deepest parts of the mantle appear uniform in seismic velocity.
True
False

18. only into the athenosphere into the lower mantle into the outer core
17. How deeply into Earth does seismic tomography data indicate that subducted oceanic lithosphere maintains coherency?
only into the athenosphere
into the lower mantle
into the outer core
into the inner core

19. 18. Earth’s magnetic field occurs due to:
convection of the outer core.
convection of the mantle.
the rotation of Earth.
the separate rotation of the inner core.

20. 19. Earth’s magenetic field is dominantly a(n) ____ field.
octopole
hexapole
quadropole
dipole

21. 20. Reversals in Earth’s magnetic field can be used to date and correlate strata of which interval of Earth’s history?
the last 50 million years
the last 170 million years
the last 550 million years
the entire 4.6 billion years of Earth’s history