Chapter 19 – Earthquakes Study Guide
Modified True/False - Indicate whether the statement is true or false.
If false, change the identified word or phrase to make the statement true.
____
1. On a seismometer, the suspended mass tends to stay at rest during an earthquake because of inertia.
____
2. If two seismic stations receive data from an earthquake, the quake’s location can be computed if Pwaves, S-waves, and surface waves have been received.
____
3. The Richter Scale measures intensity, or the damaged caused by an earthquake.
____
4. Seismic belts are relatively narrow and tend to follow tectonic plate boundaries.
____
5. A stress line is a fracture in rock along which movement occurs
____
6. S-waves are refracted, or bent, by Earth’s outer core. _________________________
____
7. The fact that a significant earthquake has not occurred within a seismic gap indicates that an
earthquake is more likely to occur in the near future.
____
8. Stress is the forces per unit area acting on crustal rocks that can lead to earthquakes
____
9. The amount of damage done to structures as a result of an earthquake is the earthquake’s
magnitude. _________________________
____ 10. A tsunami is a wave generated by vertical motions of the seafloor
Multiple Choice - Identify the choice that best completes the statement or answers the question.
____ 11. The focus is the point where _______
a. the waves originate.
b. the surface waves originate and spread out.
c. the waves are attracted.
d. the most surface damage will
occur.
____ 12. Which type of material would be best to use for construction in an area prone to earthquakes?
a. Concrete
c. Brick
b. Wood
d. Stone
____ 13. The strain which causes a material to pull apart is known as ____.
a. tension
c. stress
b. compression
d. shear
____ 14. Movement occurs along fractures in rocks when stress _____ the rocks involved.
a. equals the strength of
c. is applies to
b. overcomes the strength of
d. is less than
Chapter 19 – Earthquakes Study Guide
Use the diagram to answer the questions.
____ 15. Which point marks the epicenter of the earthquake?
a. C
c. A
b. D
d. B
____ 16. At which point will the most damage as a result of the earthquake occur?
a. A
c. C
b. D
d. B
Use the diagram to answer the questions.
____ 17. What keeps the stable part of this seismometer from moving during an earthquake?
a. its location
c. its mass
b. gravity
d. inertia
____ 18. Which part of the seismometer does not shake during an earthquake?
a. the mass
c. the rotating drum
b. the spring
d. the frame
____ 19. The stress which causes a material to twist is known as ____.
a. Tension
c. Strain
b. compression
d. Shear
Chapter 19 – Earthquakes Study Guide
Use the graph to answer the questions 19-20.
____ 21. A seismogram is located 4500 miles away from the epicenter of an earthquake. What is the
difference in time between when the P-waves reach the seismogram and the S-waves reach the
seismogram?
a. 5 1/2 minutes
c. 6 minutes
b. 10 minutes
d. 22 minutes
____ 22. P-waves reaches a seismogram 6 minutes after an earthquake occurs and the S-waves arrive 3 and a
half minutes later. How far is the seismogram from the earthquakes epicenter?
a. 2000 km
c. 3000 km
b. 1000 km
d. 4000 km
Location
Earthquake
Strain Buildup
History
Rate
many earthquakes
slow
A
few earthquakes
moderate
B
many earthquakes
fast
C
many earthquakes
moderate
D
____ 23. Using the chart above, Organize the locations from lowest to highest hazard.
a. B, A, D, C
c. C, D, A, B
b. A, B, C, D
d. B, A, C, D
____ 24. Using the chart above, Location D just experienced an earthquake. Which location will most likely
experience the next earthquake?
a. Location C because it has the highest c. It is impossible to tell because the
hazard.
proximity of the other locations to D is
not known.
b. Location A because it is just below
d. It is impossible to tell because the data
location D in hazard level.
just gives the risks for earthquakes not
a predictable forecast.
____ 25. A ____ fault forms as a result of horizontal compression.
a. blind
c. strike-slip
b. reverse
d. normal
Chapter 19 – Earthquakes Study Guide
____ 26. Deaths associated with earthquake deaths in sloping areas can result from ____.
a. tsunamis
c. formation of fault scarps
b. surface ruptures
d. landslides
____ 27. Measure of the energy released by a quake
a. magnitude
c. stress
b. intensity
d. strain
____ 28. A numerical scale of earthquake magnitude that takes into account the size of the fault rupture is the
____.
a. moment magnitude scale
c. Richter scale
b. modified Mercalli scale
d. epicentral distance scale
____ 29. The San Andreas Fault, a result of horizontal shear, is a ____ fault.
a. blind
c. reverse
b. normal
d. strike-slip
____ 30. Section of an active fault that has not experienced a significant earthquake for a long time
a. epicenters
c. strain
b. seismic gaps
d. seismic belts
____ 31. The locations of seismic belts are determined by plotting ____.
a. earthquake foci
c. earthquake epicenters
b. seismic gaps
d. epicentral distances
Matching - Match each item with the correct description below. You may use a term more than once.
a. surface wave
b. P-wave
c. S-wave
____ 32. Is refracted by Earth’s core
____ 33. Absence of this kind of waves results in a shadow zone
____ 34. Squeezes and pulls rocks in same direction as the wave travels
____ 35. Does not pass through Earth’s liquid outer core
____ 36. Does not pass through Earth’s interior at all
Completion - Complete each statement using the bold words
fault plane
normal fault
reverse fault
strike-slip fault
37. Along a(n) ____________________, movement is both horizontal and vertical, resulting in a
lengthening of the crust involved.
38. A(n) ____________________ forms as a result of horizontal compression and results in a shortening
of the crust involved.
39. In a(n) _________________________, the fracture is caused by horizontal shear and movement is
mainly horizontal.
40. The surface along which fault movement takes places is the ____________________.
Chapter 19 – Earthquakes Study Guide
Open Response Question
Use the diagram to answer the questions.
41. A. The three seismograms all detected P-waves and S-waves at different times. According to the
information, what point is the epicenter of the earth quake? Explain.
B. Suppose station #2 did not detect any P-waves or S-waves. Could the information from station
#1 and station #3 still be used to determine the location of the epicenter?
C. How has the P-waves and S-waves of an earthquake benefited the study of Earth’s interior?
D. Why is California more likely to experience earthquakes than Montana?
Chapter 19 – Earthquakes Study Guide
Answer Section
MODIFIED TRUE/FALSE
1. ANS: T
2. ANS: F
3. ANS: F
4. ANS: T
5. ANS: F
MULTIPLE CHOICE
11. ANS: A
12. ANS: B
13. ANS: A
14. ANS: B
15. ANS: A
16. ANS: C
17. ANS: D
18. ANS: A
19. ANS: D
6.
7.
8.
9.
110.
20.
21.
22.
23.
24.
25.
26.
27.
28.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
C
A or C
A
D
B
D
A
A
ANS:
ANS:
ANS:
ANS:
ANS:
F
T
T
F
T
29.
30.
31.
32.
33.
34.
35.
36.
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
ANS:
D
B
C
B
B
B
C
A
COMPLETION
37. ANS: normal fault
38. ANS: reverse fault
39. ANS: strike-slip fault
40. ANS: fault plane
OPEN RESPONSE
41. A. Point B is the epicenter of the earthquake because after all three seismograms calculated their
distance from the epicenter and drew a circle of all possible points that the epicenter could be, the
one spot where all three circles overlapped is point B.
B. They could still be used to determine the epicenter, but there would still need to be a third
seismogram reading in order to pinpoint the exact location of the epicenter. By using only two
stations, there would be two points of intersection where the epicenter would possibly be located.
C. By analyzing the changes in direction and speed of P-waves and S-waves, scientists have been able to
learn about Earth’s interior. Because S-waves to not travel through Earth’s center it was concluded that some
of Earth’s core is liquid which does not allow the back-and-forth motion of the wave to travel through it.
Also, as the waves slow down and then speed back up scientists were able to determine the composition and
thickness of the layers of Earth’s interior.
D. California lies along the Circum-Pacific Belt which is a tectonic plate boundary where 80 percent
of all earthquakes occur. The movements along these boundaries cause earthquakes. Since Montana
is not located above a boundary it is less likely to experience an earthquake.