Matching
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Match
each term with the correct description below. a. | P waves | f. | seismographs | b. | S
waves | g. | mantle | c. | seismic sea waves | h. | seismograms | d. | surface waves | i. | crust | e. | seismologists | j. | magnitude | | | | |
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1.
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largest
layer of Earth
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2.
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primary
waves
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3.
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paper record
of a seismic event
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4.
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outermost
layer of Earth
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5.
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tsunamis
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6.
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instruments
that record seismic activity
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7.
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amount of
energy an earthquake releases
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8.
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people who
study earthquakes and seismic waves
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9.
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secondary
waves
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10.
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waves that
travel outward from the epicenter
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Completion
Complete each sentence or
statement.
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11.
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____________________ move through Earth by causing particles of rocks to move back and
forth in the same direction as the waves.
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12.
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Normal
faults are created by ____________________.
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13.
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One way to
make your home seismic-safe is to put heavy items on ____________________ shelves.
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14.
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The San
Andreas Fault in California is an example of a(n) ____________________ fault.
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15.
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The Richter
scale is based on the height of the lines traced by a(n) ____________________.
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16.
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When rocks
break because of stress, the energy released is in the form of a(n)
____________________.
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17.
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An
earthquake with a(n) ____________________ of 7.2 releases about 30 times as much energy as an
earthquake that registers 6.2 on the Richter scale.
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18.
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When the
buildup of stress in Earth's crust is so great that rocks reach their _________________________, an
earthquake occurs.
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19.
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____________________ waves arrive at a seismograph station first.
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20.
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Most of the
destruction during an earthquake is caused by _________________________.
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21.
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The farther
apart primary, secondary, and surface waves are, the _________________________ the epicenter
is.
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22.
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____________________ move through Earth by causing particles in rocks to move at right
angles to the direction of the waves.
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23.
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No seismic
waves are detected in the _________________________.
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24.
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At a
____________________ fault, the rocks above the fault surface are forced up and over the rocks
surface.
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25.
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The slowest
seismic waves are ____________________.
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26.
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Primary and
secondary waves slow down when they hit the plasticlike layer of the upper mantle called the
____________________.
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27.
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The
______________________________ is the boundary between the mantle and the outer core.
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28.
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Seismologists use the _________________________ to describe the magnitude of
earthquakes.
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29.
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To locate an
earthquake's ____________________, scientist use information from the three seismograph
stations.
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30.
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The boundary
between the upper mantle and the crust is called _________________________.
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31.
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The radius
of the circle seismologists draw on a map is equal to the distance from a station to an earthquake's
____________________.
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32.
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____________________ forces cause strike-slip faults.
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Short Answer
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33.
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How are the
focus and epicenter of an earthquake different?
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34.
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Why would
securing gas appliances help make your home earthquake-safe?
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35.
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Which type
of fault is least likely to form mountains? Explain.
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36.
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How were
scientists able to use seismic information to develop a model of Earth's interior?
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37.
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How do
seismologists locate the epicenter of an earthquake?
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Problem
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Figure
11-1
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38.
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According to
Figure 11-1, what is the difference in seismic waves arrival time if the epicenter is 5,000 km
away?
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39.
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Using Figure
11-1, how far away is the epicenter if the difference in seismic wave arrival times is 7
minutes?
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Multiple Choice
Identify the
letter of the choice that best completes the statement or answers the question.
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40.
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Seismic
waves ____ when they reach the bottom of the crust. a. | stay the
same | c. | stop | b. | slow down | d. | speed up | | | | |
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41.
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The ____
waves are the first to reach a seismograph after an earthquake. a. | tsunami | c. | surface | b. | secondary | d. | primary | | | | |
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42.
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____ is the
force that causes plates to move sideways past each other. a. | Shear | c. | Compression | b. | Elastic limit | d. | Tension | | | | |
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43.
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The point in
Earth's interior where the energy release of an earthquake occurs is the ____. a. | epicenter | c. | focus | b. | inner core | d. | fault | | | | |
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44.
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Primary
waves ____ when they hit the liquid outer core. a. | stay the same | c. | speed up | b. | slow down | d. | stop | | | | |
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45.
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A person
located twice as far from an epicenter of an earthquake as another person will notice that the time
between the arrival of the primary and secondary waves will be ____. a. | the
same | c. | unnoticeable | b. | larger | d. | reduced | | | | |
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46.
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At a(n) ____
fault, rocks on either side of the fault surface move past each other. a. | elastic | c. | strike-slip | b. | normal | d. | reverse | | | | |
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47.
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____ is the
force that pulls rocks apart. a. | Compression | c. | Shear | b. | Tension | d. | Elastic limit | | | | |
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48.
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____ faults
are caused by tensional forces. a. | Strike-slip | c. | Elastic | b. | Reverse | d. | Normal | | | | |
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49.
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Secondary
waves ____ when they hit the liquid outer core. a. | speed up | c. | stop | b. | slow down | d. | stay the same | | | | |
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50.
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All of the
following will improve safety factors during an earthquake EXCEPT to ____. a. | take heavy objects down
from high shelves | b. | stand next to a window | c. | make sure hot-water
heater are held securely in place | d. | study an area's earthquake history | | |
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51.
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When the
force on rocks is great enough, they break, producing vibrations called ____. a. | strains | c. | faults | b. | earthquakes | d. | stresses | | | | |
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52.
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The
magnitude of an earthquake is measured by the ____. a. | Richter
scale | c. | moho
discontinuity | b. | modified Meralli scale | d. | elastic limit | | | | |
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53.
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Once the
elastic limit of rocks is passed, they break and move along surfaces called ____. a. | strains | c. | stresses | b. | earthquakes | d. | faults | | | | |
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54.
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____ is the
force that squeezes rocks together. a. | Shear | c. | Elastic limit | b. | Compression | d. | Tension | | | | |
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55.
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Along a(n)
____ fault, rock above the fault surface moves upward in relation to rock below the fault
surface. a. | elastic | c. | reverse | b. | normal | d. | strike-slip | | | | |
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56.
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Scientists
discovered changes in Earth's interior by studying ____. a. | tsunamis | c. | changes in seismic
waves | b. | tides | d. | all of the above | | | | |
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57.
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The height
of the lines traced on paper is a measure of the energy released or the ____ of the
earthquake. a. | intensity | c. | stress | b. | strain | d. | magnitude | | | | |
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58.
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Along a(n)
____ fault, rock above the fault surface moves downward in relation to rock below the fault
surface. a. | strike-slip | c. | elastic | b. | reverse | d. | normal | | | | |
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59.
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____ faults
are caused by shear forces. a. | Reverse | c. | Elastic | b. | Normal | d. | Strike-slip | | | | |
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60.
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____ faults
are caused by compressional forces. a. | Strike-slip | c. | Elastic | b. | Normal | d. | Reverse | | | | |
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61.
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The most
destructive seismic wave are ____. a. | primary waves | c. | surface waves | b. | secondary
waves | d. | P-waves | | | | |
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62.
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At least
____ seismographs are needed to accurately locate an earthquake epicenter.
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63.
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Most
earthquakes happen ____. a. | without warning | b. | in areas where
earthquakes have occurred in the past | c. | along plate boundaries | d. | all of the
above | | |
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