Deck 8: A Violent Pulse: Earthquakes

Question 1

The intersection between a fault plane and the ground surface is called the ____________.

A) dip line
B) plunge
C) fault trace
D) seismic interface

Answer 1

C

Question 2

The quantity of offset that occurs along a fault is termed ____________.

A) fault gouge
B) the fault gauge
C) displacement
D) accumulation

Answer 2

C

Question 3

If a fault is nearly vertical in orientation and the two walls of rock on opposite sides slide past one another horizontally,the fault is termed ____________.

A) normal
B) reverse
C) strike slip
D) thrust

Answer 3

C

Question 4

Earthquakes are a result of ____________.

A) a sudden change in atmospheric pressure
B) mantle upwelling
C) erosion
D) lithosphere-plate movement

Question 5

All discovered faults are likely to experience earthquakes in the next few hundred years.

Question 6

If,during an earthquake,a hanging wall slides upward relative to a footwall,the fault is termed ____________ if the fault is steep (closer to vertical than horizontal).

A) normal
B) reverse
C) strike slip
D) thrust

Question 7

A surface along which rock on opposed sides is offset by earthquake-induced slip is called a ____________.

A) joint
B) fault
C) fold
D) wall

Question 8

A primary force opposing motion on all faults is ____________.

A) magnetic attraction among iron-rich minerals
B) gravity
C) friction
D) van der Waals force

Question 9

If,during an earthquake,a hanging wall slides upward relative to a footwall,the fault is termed ____________ if the fault is shallow (much closer to horizontal than vertical).

A) normal
B) reverse
C) strike slip
D) thrust

Question 10

Faulting and earthquakes are examples of ____________.

A) brittle behavior
B) ductile behavior

Question 11

A fault cannot slip forever because __________ .

A) it exhibits no elastic behavior
B) once the elastic bending that has built up is released, the blocks no longer move
C) the vibration caused by the slipping eventually ceases
D) friction eventually slows and stops the movement

Question 12

At any point along the fault plane surface of an oblique (nonvertical)fault,the ____________.

A) hanging wall lies vertically above the footwall
B) footwall lies vertically above the hanging wall
C) hanging wall lies to the left of the footwall
D) footwall lies to the left of the hanging wall

Question 13

Of the following,which causes the most earthquakes?

A) the sudden formation of a new fault
B) a sudden slip on an existing fault
C) the explosion of a volcano
D) a giant landslide

Question 14

Aftershocks following a major earthquake ____________.

A) may continue for days after the initial earthquake
B) are mostly much smaller than the original earthquake
C) may occur on the same fault as the original earthquake, or a different fault
D) All of the above are correct.

Question 15

Faults that have moved recently or are likely to move in the future are referred to as ____________.

A) passive
B) active
C) normal
D) reverse

Question 16

The stress that builds on a preexisting fault that has previously ruptured _____________.

A) is great enough to cause new fractures
B) must overcome the force of friction to cause an earthquake
C) is analogous to a broken stick
D) is nonexistent

Question 17

Periods of intermittent sliding on a fault as a result of the release of stress during episodes of displacement,followed by stress buildup to the point that the fault is reactivated,is termed ____________.

A) chaotic faulting
B) thrust faulting
C) stick-slip behavior
D) reverse faulting

Question 18

Movement on a fault may occur without generating earthquakes.

Question 19

Geologists who specifically study earthquakes are called ____________.

A) seismologists
B) paleontologists
C) vulcanologists
D) speleologists

Question 20

If,during an earthquake,a footwall slides upward relative to a hanging wall,the fault is termed ____________.

A) normal
B) reverse
C) strike slip
D) thrust

Question 21

This fundamental principle of physics is the basis behind the effectiveness of a seismometer.

A) The change of momentum of a body is proportional to the impulse impressed on the body, and happens along the straight line on which that impulse is impressed.
B) The mutual forces of action and reaction between two bodies are equal, opposite, and collinear.
C) Every body persists in its state of being at rest or of moving uniformly straight forward, except insofar as it is compelled to change its state by force impressed.
D) To every action there is always an equal and opposite reaction.

Question 22

Which type of fault does NOT,by definition,have a fault trace?

A) normal fault
B) reverse fault
C) blind fault
D) None of the above are correct; all faults have recognizable traces.

Question 23

Body waves include ____________.

A) both S- and P-waves
B) both L- and R-waves
C) both surface and interior waves
D) P-waves only

Question 24

How many seismic stations are necessary to find the epicenter of an earthquake?

A) one
B) two
C) three
D) four

Question 25

Which earthquake intensity scale assesses the effects of an earthquake on humans and human-made structures?

A) Richter scale
B) Mercalli scale
C) seismic-moment magnitude scale

Question 26

As a seismologist examining a seismogram,you would know that the third set of waves displayed ____________.

A) would cause the most damage
B) are S-waves
C) are P-waves
D) are an indication that the major earthquake is over and that the aftershocks have begun

Question 27

Which earthquake severity scale takes vibration caused only by the S-waves into account when estimating the size of an earthquake?

A) Richter scale
B) Mercalli scale
C) seismic-moment magnitude scale

Question 28

Generally,which type of earthquake waves travel fastest?

A) interior waves
B) R-waves
C) surface waves
D) body waves

Question 29

Which earthquake severity scale takes into account the type of rock that has been fractured?

A) Richter scale
B) Mercalli scale
C) seismic-moment magnitude scale

Question 30

In order for an earthquake to occur where you live,which of the following must be true?

A) You live in a seismic belt.
B) Energy must be released in the Earth's crust.
C) You live on the Pacific Ocean.
D) Slip must occur along a fault.

Question 31

The point within Earth where an earthquake takes place is termed the ____________.

A) hypocenter (focus)
B) epicenter
C) eye of the fault
D) vertex

Question 32

The key to finding the location of an earthquake's epicenter is measuring the ____________.

A) difference between the time that the P-wave arrives and the time that the S-wave arrives at the seismometer station
B) total time it takes for the P-wave and then the S-wave to arrive at the seismometer station
C) difference between the time the S-wave has reached one seismometer station and the time the S-wave has reached another station
D) difference between the time the P-wave has reached one seismometer station and the time the P-wave has reached another station

Question 33

All else being equal,an earthquake that strikes in the eastern United States would produce shaking that would be felt ____________ than one that occurred in the western United States.

A) over a greater distance
B) over a lesser distance
C) over the same distance

Question 34

Seismometers,being able to detect ground movements of a millionth of a millimeter,are useful to governments worldwide for detecting not only earthquakes,but _______________.

A) landslides
B) nuclear bomb tests
C) avalanches
D) bombing raids

Question 35

A coiled spring would be useful in illustrating a ____________ wave.

A) surface
B) body
C) shear
D) compressional

Question 36

Vertical motion seismographs record earthquakes through the production of a squiggly diagram called a ____________.

A) wave sheet
B) seismogram
C) pictogram
D) camera lucida

Question 37

Which type of seismic wave has the highest velocity?

A) L-wave
B) P-wave
C) R-wave
D) S-wave

Question 38

The point on Earth's surface directly above the point where an earthquake occurs is termed the ____________.

A) hypocenter (focus)
B) epicenter
C) eye of the fault
D) vertex

Question 39

Earthquake waves that pass through the interior of Earth are termed ____________.

A) interior waves
B) R-waves
C) surface waves
D) body waves

Question 40

Surface waves ____________.

A) travel more rapidly than body waves
B) produce most of the damage to buildings during earthquakes
C) are the first waves initially produced in an earthquake
D) are the first waves to arrive at a seismograph station after an earthquake

Question 41

Sandy substrate is susceptible to ____________ during an earthquake.

A) displacement
B) collapse
C) liquifaction
D) faulting

Question 42

Why do some earthquakes last longer than others?

A) The substrate in which it occurs is stronger.
B) The distance from the epicenter is greater.
C) The frequency of the waves is greater.
D) The distance from the focus is greater.

Question 43

Which of these areas of the United States would you expect to have the highest occurrence of seismic activity?

A) Southeast
B) West
C) Northeast
D) Central

Question 44

Which earthquake severity scale measures the amplitude of deflection of a seismograph pen,standardized to an idealized distance of 100 km between epicenter and seismograph?

A) Richter scale
B) Mercalli scale
C) seismic-moment magnitude scale

Question 45

A tsunami is ____________.

A) an earthquake-generated sea wave that can sometimes destroy coastal cities thousands of kilometers from its source
B) a sloshing of water back and forth within a lake or bay
C) the amount of change in elevation of local sea level caused by a surging wave
D) the tendency of wet, clay-rich soils to behave like a liquid during an earthquake

Question 46

Short-term predictions of earthquake behavior ____________.

A) have saved millions of lives in the past decade alone
B) have been largely unreliable
C) are primarily based on the behavior patterns of farm animals
D) are correct approximately 50% of the time

Question 47

Long-term prediction of earthquake behavior ____________.

A) is based on past earthquake activity
B) works on the principle that zones of past seismicity will be active in the future
C) includes the notion of seismic gaps-places where an earthquake is "overdue"
D) All of the above are correct.

Question 48

What geological setting(s)would you expect to produce seismic activity?

A) rift valley
B) basin
C) collisional mountain belt
D) All of the above are correct.

Question 49

Virtually all of the deaths attributed to major earthquakes have resulted from the collapse of buildings.

Question 50

Seismic retrofitting is the process of __________.

A) predicting earthquakes
B) strengthening existing buildings and structures
C) mapping areas prone to earthquakes
D) releasing energy

Question 51

According to the moment magnitude scale (Mw)-a magnitude 8 earthquake results in 1,000 times greater amplitude than a magnitude ____________ earthquake.

A) 9
B) 5
C) 7
D) 4

Question 52

How can damage and injury be minimized in areas prone to seismic activity?

A) earthquake zoning
B) engineering controls
C) warning systems
D) All of the above are correct.

Question 53

Earthquakes that occur in a band called a ____________ can be used to track the motion of subducted oceanic lithosphere.

A) Wegener belt
B) seismic gap
C) Wadati-Benioff zone

Question 54

Which of the following scales was used to measure the intensity of the listed earthquakes?

A) Mercalli
B) Seismic-moment
C) Richter
D) None of the above are correct.

Question 55

An earthquake occurs with an epicenter in the town of New Madrid,Missouri,in the interior of the North American Plate.Where might the hypocenter of this earthquake plausibly be found?

A) in New Madrid ("hypocenter" and "epicenter" mean precisely the same thing)
B) 10 km south of New Madrid
C) 20 km beneath New Madrid
D) 200 km beneath New Madrid

Question 56

Earthquakes are likely to occur along ____________.

A) convergent-plate boundaries only
B) divergent-plate boundaries only
C) transform-plate boundaries only
D) All of the above are correct.

Question 57

On December 26,2004,a magnitude 9 earthquake generated a tsunami that devastated coastlines along the ____________.

A) Atlantic Ocean
B) Arctic Ocean
C) Indian Ocean
D) Pacific Ocean

Question 58

Which earthquake severity scale varies from locality to locality for a single earthquake?

A) Richter scale
B) Mercalli scale
C) seismic-moment magnitude scale

Question 59

If you heard on the news today that an earthquake measured an 8.2 on the Richter scale,what other conclusions could you make based on knowledge garnered from this chapter?

A) that this was the only type of earthquake magnitude scale used
B) that there will be "moderate to serious damage" based on a subjective assessment of damage and effects
C) that, according to the Modified Mercalli Intensity Scale, maximum intensity will be at levels IX to X
D) that the earthquake will be described as "great"

Question 60

Medium- and deep-focus earthquakes occur along ____________.

A) convergent-plate boundaries only
B) divergent-plate boundaries only
C) transform-plate boundaries only
D) All of the above are correct.