Deck 8: A Violent Pulse: Earthquakes

Question 1

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 1

A

Question 2

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 2

C

Question 3

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)Wadati-Benioff zone
D)Richter zone

Answer 3

C

Question 4

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 5

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

Question 6

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 7

The vast majority of earthquakes occur ________.

A)along transform-plate boundaries only
B)near hotspots
C)along passive margins
D)along all types of plate boundaries

Question 8

________ travel with a compressional motion.

A)Love waves
B)Rayleigh waves
C)P-waves
D)S-waves

Question 9

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 10

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 11

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

A)convergent-plate boundaries
B)divergent-plate boundaries
C)transform-plate boundaries
D)hotspots

Question 12

Earthquakes often occur along ________.

A)bedding planes
B)terminal moraines
C)fault zones
D)river valleys

Question 13

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

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

Question 14

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 15

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

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

Question 16

An increase in size of one unit of magnitude translates to ________ the ground motion.

A)1 time
B)2 times
C)32 times
D)10 times

Question 17

The recurrence of earthquakes along a single fault is referred to as ________.

A)stick-slip behavior
B)elastic-rebound theory
C)seismic repetition theory
D)slip-transfer theory

Question 18

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

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

Question 19

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 20

A primary force opposing motion on all faults is ________.

A)covalent bonds
B)gravity
C)friction
D)the Van der Waals force

Question 21

The Mercalli intensity scale tends to be very subjective and thus is generally only used for historical earthquakes that were near people but were not recorded by seismometers.Why might the Mercalli scale be subjective?

A)It relies on testimony from people.
B)It does not take into account distance.
C)It can only be used for large earthquakes.
D)It cannot be used in heavily populated areas.

Question 22

Which of the following does NOT affect the severity of damage from an earthquake?

A)weather
B)distance
C)duration
D)magnitude

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

According to the image below,where was the epicenter of the earthquake?

A)New York
B)Florida
C)Canada
D)South Carolina

Question 25

The moment magnitude is based on the ________ and ________ of the earthquake.

A)amplitude;rupture area
B)amplitude;distance
C)rupture area;amount of damage
D)amount of damage;distance

Question 26

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 north New Madrid

Question 27

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

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

Question 28

Which type of seismic wave has the fastest velocity?

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

Question 29

What is the magnitude of the earthquake shown in the image below?

A)5
B)24
C)220
D)6

Question 30

The ________the earthquake,the less severe the damage will be.

A)larger the magnitude of
B)shorter the duration of
C)farther you are from
D)closer you are to

Question 31

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 have very large areas for potential rupture and thus can produce large earthquakes.
D)This is not true.Transform faults (like the San Andreas)can produce the largest earthquakes.

Question 32

Earthquakes can often produce ________ by breaking gas lines.

A)landslides
B)flooding
C)sinkholes
D)fires

Question 33

According to the image below,which seismic wave phase is likely to cause the most damage?

A)P-wave
B)S-wave
C)surface wave
D)aftershock

Question 34

According to the diagram below,the energy released by the 1994 Northridge earthquakes was roughly the same as the energy released by ________.

A)the H-bomb
B)Mount St.Helens
C)the tornado
D)the hurricane

Question 35

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 36

Which seismic wave phase causes the ground to roll like a wave?

A)P-wave
B)S-wave
C)Rayleigh wave
D)Love wave

Question 37

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 38

The larger the ________ of the wave,the more severe the damage will be.

A)travel-time curve
B)epicenter
C)seismometer
D)amplitude

Question 39

________ occur(s)when earthquakes causes pore pressure to increase,which in turn causes grains to separate and compact.

A)Liquefaction
B)Aftershocks
C)Normal faults
D)Landslides

Question 40

A tsunami is ________.

A)a sea wave generated by a displacement of water
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 41

Why is an empty field the safest place to be in an earthquake?

Question 42

Explain why tsunamis are NOT tidal waves.

Question 43

Where is the best place to be in an earthquake?

A)in an empty field
B)in a brick house
C)in a doorway
D)on the beach

Question 44

Long-term prediction methods include ________.

A)early warning systems
B)behavior of animals
C)seismic risk assessment
D)recognition of foreshocks

Question 45

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 46

Why do deep-focus earthquakes occur along convergent plate boundaries? Why do they not occur along divergent or transform boundaries?

Question 47

How is the Mercalli intensity scale used to determine the magnitude of an earthquake? What errors might be associated with this technique?

Question 48

Much of the capitol city of Port-au-Prince was destroyed during the 2010 Haiti earthquake despite the fact that similarly sized earthquakes in other cities did very little damage.What caused so much damage during the Haiti earthquake?

A)A tsunami wiped out the city.
B)Landslides covered large areas.
C)The buildings were poorly built.
D)The residents did not evacuate in time.

Question 49

Early warning systems use computers to detect a nearby earthquake and send an emergency alert to warn of the event.Which seismic phase is the system detecting when it sends the alert?

A)Love wave
B)Rayleigh wave
C)P-wave
D)S-wave

Question 50

Why is an early warning system NOT considered a short-term earthquake prediction tool?

Question 51

Making better ________ is the best way to try to prevent earthquake damage.

A)seismometers
B)magnitude scales
C)buildings
D)seismograms

Question 52

The ________ of a fault gives the average time between events.

A)displacement
B)exceedance probability
C)recurrence interval
D)annual probability

Question 53

Earthquake ________ is a means of deciding where the ground is stable enough to build on in earthquake-prone areas.

A)mitigation
B)zoning
C)retrofitting
D)prevention

Question 54

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 55

Evidence of a past earthquake may be found by looking for offset beds or ________.

A)liquefaction
B)sand volcanoes
C)stress fractures
D)foliation