Deck 10: A Violent Pulse: Earthquakes

Question 1

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 ________ fault.Refer to the figure below for an example of such a feature.

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

Answer 1

C

Question 2

At any point along the surface of any nonvertical fault such as is shown in the figure below,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

Answer 2

A

Question 3

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

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

Answer 3

B

Question 4

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

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

Question 5

A primary force opposing motion on all faults is ________.

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

Question 6

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 7

Most earthquakes are a result of ________.

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

Question 8

Faulting and earthquakes are examples of ________ and generally occur when rocks are relatively ________.

A)brittle deformation;cold
B)ductile deformation;cold
C)brittle deformation;hot
D)ductile deformation;hot

Question 9

Geologists who specifically study earthquakes are called ________.

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

Question 10

During an earthquake,if a footwall slides upward relative to a hanging wall (as shown in the figure below),the fault is termed a ________ fault.

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

Question 11

The quantity of motion that occurs along a fault is termed ________.

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

Question 12

Periods of intermittent sliding on a fault because of stress release during episodes of slip,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 13

During an earthquake,if the hanging wall slides upward relative to the footwall,the fault is termed a ________ fault if the fault is steep (closer to vertical than horizontal).Refer to the figure below for an example of such a feature.

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

Question 14

Which type of seismic wave has the fastest velocity?

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

Question 15

Slow and steady movement on a fault that does not generate earthquakes is termed ________.

A)antislip
B)creep
C)stick-slip
D)elastic rebound

Question 16

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

A)normal fault
B)reverse fault
C)blind fault
D)All faults have recognizable traces.

Question 17

As shown in the figure below,a coiled spring would be useful in illustrating any ________ wave.

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

Question 18

Which of the following statements is NOT true? Aftershocks after a major earthquake ________.

A)may continue for days,weeks,or years 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)typically occur only on reverse faults in subduction zones as a result of high pressures

Question 19

During an earthquake,if a hanging wall slides upward relative to a footwall,the fault is termed a ________ fault if the fault is shallow (much closer to horizontal than vertical).Refer to the figure below for an example of such a feature.

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

Question 20

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

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

Question 21

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 22

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 23

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 24

Earthquake waves that travel along Earth's surface are termed ________.

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

Question 25

If an earthquake's magnitude is measured based on the Richter scale,how is this abbreviated?

A)ML
B)MS
C)mb
D)MR

Question 26

Which earthquake scale uses the amplitudes of several different waves,the amount of slip,and the dimensions of the slipped area on the fault and is therefore considered the most accurate magnitude scale?

A)the Richter scale
B)the Mercalli scale
C)the moment magnitude scale
D)the surface-wave magnitude scale

Question 27

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

A)the Richter scale
B)the Mercalli scale
C)the moment magnitude scale
D)the surface-wave magnitude scale

Question 28

The vast majority of earthquakes occur ________.

A)along transform-plate boundaries only
B)near hot spots
C)along passive margins
D)along any plate boundary

Question 29

Vertical motion seismographs record earthquakes by producing a squiggly diagram called a ________.

A)wave sheet
B)seismogram
C)pictogram
D)seismograph

Question 30

Which earthquake scale is used to assess the effects of an earthquake on humans and human-made structures?

A)Richter scale
B)Mercalli scale
C)moment magnitude scale
D)surface-wave magnitude scale

Question 31

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

A)over a greater distance
B)over a lesser distance
C)over the same distance
D)There is no consistent pattern of shaking distance in these two regions.

Question 32

Generally,which type of earthquake waves travel with the slowest velocity?

A)S-waves
B)P-waves
C)surface waves
D)All earthquake waves travel at the same speed.

Question 33

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

A)Wegener belt
B)seismic gap
C)Wadait-Benioff zone
D)Richter zone

Question 34

Why do subduction zones have the potential to create the largest earthquakes on Earth?

A)The convergence creates exceedingly large amounts of friction.
B)Subduction zones create the highest pressures of any plate boundary.
C)Subduction zones are coldest with increasing depth,so the potential rupture area is very large.
D)This is not true.Transform faults (like the San Andreas)can produce the largest earthquakes.

Question 35

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

A)the Richter scale
B)the Mercalli scale
C)the moment magnitude scale
D)the surface-wave magnitude scale

Question 36

Earthquake waves that pass through Earth's interior are termed ________.

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

Question 37

The greatest earthquake ever recorded by seismographs occurred in 1960 in ________ and measured a magnitude of ________.

A)Japan;9.3
B)Alaska;9.5
C)Chile;9.5
D)Portugal;9.8

Question 38

According to the moment magnitude scale (Mw),a magnitude 8 earthquake would be 1,000 times greater than a magnitude ________ earthquake.

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

Question 39

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)20 km south of New Madrid
C)20 km beneath New Madrid
D)200 km beneath New Madrid

Question 40

At a minimum,how many seismic stations are necessary to locate the epicenter of an earthquake?

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

Question 41

Which geological setting would you NOT expect to produce a large amount seismic activity?

A)a rift valley
B)a mid-ocean ridge
C)a collisional mountain belt
D)the interior of a tectonic plate

Question 42

Seismic retrofitting is the process of ________.

A)predicting future earthquakes
B)strengthening existing buildings and structures
C)mapping areas prone to earthquakes
D)fitting earthquake data after an event to see if it should have been predicted

Question 43

On December 26,2004,a magnitude 9.3 earthquake generated a tsunami that devastated coastlines on the ________ Ocean.

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

Question 44

Which of the following is NOT true concerning the long-term forecasting of earthquakes? Long-term forecasting ________.

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)is not possible

Question 45

Tsunamis are more destructive than wind-driven storm waves primarily because ________.

A)tsunamis always have larger heights (amplitude)
B)tsunamis have longer wavelengths and thus larger volumes of water are involved
C)the tides that cause tsunamis can be very erratic and unpredictable
D)tsunamis also generate seismic waves that can destroy buildings

Question 46

Medium- and deep-focus earthquakes occur along only ________.

A)convergent-plate boundaries
B)divergent-plate boundaries
C)transform-plate boundaries
D)hot spots

Question 47

Which of the following is NOT true about tsunamis?

A)They can be generated by uplift of the seafloor during an earthquake.
B)They are just as dangerous away from the coast where water depths are great.
C)They can travel at speeds approaching that of a jet in the open ocean.
D)They grow taller as they approach coastlines because friction slows the wave.

Question 48

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 49

A tsunami is ________.

A)a sea wave generated by an earthquake,landslide,or meteor impact that may destroy coastal cities thousands of kilometers from its source
B)a sloshing of water back and forth within a lake or a bay
C)a wave caused by unusually large tidal forces
D)the tendency of wet,clay-rich soils to behave like a liquid during an earthquake

Question 50

Wet and unconsolidated substrates are uniquely susceptible to ________ during an earthquake.

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