Name: ____________________
Topic 12: Earth’s Dynamic Crust and Interior (p.213 – 244)
p.213
1. What is the relationship between the crust and the lithosphere?
The crust is part of the lithosphere.
2. The concept of original horizontality assumes that Sedimentary rock and some
extrusive igneous rocks, such as lava flows, form in horizontal layers parallel to Earth’s
suface.
3. FOLDED rock layers are bent or curved. TILTED rock layers are slanted or tipped.
FAULTED rock layers are offset or displaced along a type of crack called a fault. A fault is a
crack in a mass of rock along which THERE HAS BEEN DISPLACEMENT, SHIFTING,
OR MOVEMENT OF THE ROCK LAYERS.
p.214
4. Sketch horizontal, tilted, folded and faulted strata (figure 12-1)
p.215 – Earthquakes and Igneous Activity, Including Volcanoes
5. Define Earthquake:
NATURAL RAPID SHAKING OF THE LITHOSPHERE CAUSED BY THE
RELEASE OF ENERGY STORED IN THE ROCKS
6. Earthquakes start at the FOCUS , from which the waves of energy are emitted. The
location on the Earth’s surface directly above the focus is called the EPICENTER.
7. Label the fault, focus and epicenter on the diagram below (based on figure 12-2).
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EPICNETER
FAULT
FOCUS
p.216 – Earthquake Waves
8. P-waves, also called PRIMARY WAVES, cause the particles they travel through
to vibrate IN THE DIRECTION THE WAVES ARE MOVING . The slower S-waves,
also called SECONDARY WAVES, cause the particles they travel through to vibrate
AT RIGHT ANGLES TO THE DIRECTION THE WAVES ARE MOVING.
9. P-waves always travel (FASTER / slower) than S-waves through the same material.
10. How does the density of the material seismic waves travel through affect the velocity of
the waves? THE MORE DENSE THE MATERIAL, THE FASTER THE VELOCITY
11. Put a check in the box if the wave can travel through matter in this state.
P-wave
S-wave
Solid
√
√
Liquid
√
Gas
√
p.217 – Location of an epicenter
12. What information can be determined by knowing the time interval between the arrival of
the p-waves and the s-waves?
DISTANCE TO THE EPICENTER
Figure 12-4 is very similar to p.11 of the ESRT’s. Make sure you can use the Earthquake PWave and S-Wave Travel Time chart
13. To find the position of the epicenter, at least THREE seismograph locations must be
used.
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14. Study figure 12-5. Explain how the distance from the epicenter of three seismograph
locations can be used to locate the epicenter of an earthquake. THE THREE CIRCLES
INTERSECT AT ONE LOCATION
You need to be able to calculate an Earthquakes Origin Time. The general equation is:
Arrival Time
- _Travel Time__
Origin Time
p.218
15. What is an earthquake’s magnitude a measure of? How does a seismograph indicate the
magnitude of an earthquake? STRENGTH OF AN EARTHQUAKE – HEIGHT OF THE
WIGGLES ON THE SEISMOGRAPH
16. Can earthquakes be accurately predicted? Explain. NOT REALLY, GENERAL
LONG-TERM PREDICTIONS HAVE BEEN MADE BECAUSE EQ’S OCCUR IN
SPECIFIC ZONES.
p.219
17. What are some prevention / planning strategies that can be done on a community level to
protect its citizens? PROPER BUILDING CONSTRUCTION
p.220
18. In figure 12-8, what produced the tsunami? UNDERWATER EARTHQUAKE
19. Define Volcano: A MOUNTAIN COMPOSED OF EXTRUSIVE IGNEOUS
ROCK.
20. List at least two natural hazards associated with volcanic eruptions: FLOWING LAVA
OR VOLCANIC ASH. MUDSLIDES
p.221
21. When magma moves upward before volcanic eruptions, it pushes rock out of the way,
causing hundreds of EARTHQUAKES.
p.226 – A model of Earth’s Interior
22. How have scientists learned about the Earth’s interior?
STUDY OF SEISMIC WAVES
23. How is the study of the Earth’s interior similar to studying the human body with x-rays?
USING ENERGY WAVES TO VISUALIZE WHAT WE CAN’T SEE WITH OUR
OWN EYES.
p.227
24. What is the boundary / interface that separates the mantle from the crust? MOHO
25. What happens to seismic waves in the asthenosphere? & Why? DECREASE IN
VELOCIYTY. BECAUSE THE ASTHENOSPHERE IS PARTIALLY MELTED
ROCKS.
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26. Beneath the mantle Earth’s core is divided into two parts – the INNER
and the OUTER .
27. Study figure 12-11. What is a shadow zone? And why does it exist? A REGION
WHERE NO SEISMIC WAVES ARE RECORDED. S-WAVES CANNOT TRAVEL
THROUGH THE LIQUID OUTER CORE.
p.228
28. Why is it believed that the inner core is solid? THE WAY THE P-WAVES TO
LOCATIONS ON THE OPPOSITE SIDE OF THE WORLD FROM THE FOCUS.
Use figure 12-11 to answer 29 - 31
29. What type of seismic
waves are recorded here?
P & S WAVES
30. What kind of seismic
waves are recorded here?
NONE
31. What kind of seismic waves
are recoded here?
P- WAVES ONLY
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p.229 – Plate Tectonics
32. Is there a difference between plates, lithospheric plates, and tectonic plates? NO
33. Approximately how much do the lithospheric plates move each year? A FEW
CENTIMETERS A YEAR
p.230
34. Study figure 12-3. What do these diagrams show us about the positions of the
continents? THE CONTINENTS HAVE CHANGED POSITIONS THROUGHOUT
HISTORY
p.231
35. Define Divergent Plate Boundary: WHEN PLATES SEPARATE
36. What features other than lava flows are associated with divergent boundaries?
VOLCANOES, EARTHQUAKES, RIFT VALLEYS
37. When divergence is within the oceanic crust, the faulting and volcanic activity result in a
MID-OCEAN RIDGE, a mountain range at the bottom of the ocean that is composed mostly
of volcanoes and lava flows. The mid-ocean ridges often have a central depression or RIFT
VALLEY , as shown in figures 12-14b.
38. Define Convergent Plate Boundary: WHEN PLATES COLLIDE (COME
TOGETHER)
39. There are 3 varieties of convergent plate boundaries:
A. Oceanic   Oceanic
B. Continental   Continental
C. CONTINENTAL   OCEANIC
40. Which varieties result in Subduction? What decides which of the colliding plates is
subducted? OCEANIC & OCEANIC AND CONTINENTAL & OCEANIC
p.232
41. Sketch figure 12-14c.
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p.233
42. What happens when two continental plates collide? Name an example.
MOUNTAINS FORM  HIMALAYAS
43. What is the name of the famous Transform Plate Boundary in the United States?
SAN ANDREAS FAULT
44. What is the driving force behind Plate Tectonics?
CONVECTION CURRENTS IN THE MANTLE
45. Explain the similarity between Hawaii, Yellowstone, and possibly the Adirondacks.
HOT SPOTS – VOLCANIC ACTIVITY AWAY FROM PLATE BOUNDARIES
p.234 – Effects of Plate Tectonics (I think this is better titled Evidence for Plate Tectonics)
46. What about the appearance of the continents suggests the existence of a past
supercontinent? JIGSAW PUZZLE FIT
47. How can the fossil remains of a creature like Glossopteris lend credit to the theory of
plate tectonics? THE CREATURE IS FOUND ALL OVER THE GLOBE. UNLESS
THE CONTINENTS WERE ONCE CONNECTED IT IS UNLIKELY THAT THIS
ORGANISM WOULD GET TO ALL THE LANDMASSES.
48. What is strange about finding coal deposits near the poles and evidence of glaciation near
the equator? How does the theory of plate tectonics explain these observations? COAL IS
FORMED IN TROPICAL ENVIORMENTS.
THE FARTHER AWAY FROM THE RIDGE THE
OLDER THE ROCKS.
Age of bedrock
49. What is the relationship between age of the bedrock and the distance from the mid-ocean
ridge? Represent it graphically too.
Distance from mid-ocean ridge 
p.235
50. What happens to Earth’s magnetic poles every several thousands of years? It is the
symmetry of these magnetic reversals that supports Plate Tectonic Theory! Go back to figure
12-14a and 12-14b to recognize the symmetry between plate 1 and plate 2. EARTH’S
POLARITY FLIPS ABOUT EVERY 20,000 YEARS
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