Deck 13: Earthquakes

Question 1

What does the elastic rebound theory describe?

A)the build-up and release of stress during an earthquake
B)the fluctuations in groundwater prior to an earthquake
C)the formation of mountain ranges by successive earthquakes
D)the uplift of the crust in response to erosion

Answer 1

A

Question 2

Energy waves that are released during an earthquake are called

A)shock waves.
B)elastic waves.
C)stress waves.
D)seismic waves.

Answer 2

D

Question 3

What is the maximum amount of slip on a fault during an earthquake?

A)approximately 1 meter
B)approximately 20 meters
C)approximately 100 meters
D)approximately 200 meters

Answer 3

B

Question 4

The moment magnitude of an earthquake is proportional to

A)the area of the fault break.
B)the seismic energy released during the rupture.
C)the area of the fault break and the seismic energy released during the rupture.
D)neither the area of the fault break nor the seismic energy released during the rupture.

Question 5

How many seismograph stations are needed to locate the epicenter of an earthquake?

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

Question 6

What type of seismic waves are S waves?

A)compressional waves
B)shear waves
C)surface waves
D)tsunamis

Question 7

How do rock particles move during the passage of an S wave through the rock?

A)back and forth parallel to the direction of wave travel
B)back and forth at right angles to the direction of wave travel
C)in a rolling circular motion
D)in a rolling elliptical motion

Question 8

Rocks that undergo elastic deformation will

A)return to their original shape once the stress is released.
B)cause a large magnitude earthquake.
C)undergo permanent deformation.
D)cause a small magnitude earthquake.

Question 9

Approximately how many magnitude 7 earthquakes occur each year?

A)one
B)10
C)100
D)1000

Question 10

Who developed the procedure used to measure the size of an earthquake?

A)Henri Darcy
B)Charles Darwin
C)James Hutton
D)Charles Richter

Question 11

Which of the following statements regarding aftershocks is true?

A)The number and sizes of aftershocks both decrease with time.
B)The number of aftershocks decreases with time,while the sizes of aftershocks increase with time.
C)The number of aftershocks increases with time,while the sizes of aftershocks decrease with time.
D)The number and sizes of aftershocks both increase with time.

Question 12

The ground motion during a Richter magnitude 8 earthquake is ______ times greater than the ground motion during a Richter magnitude 6 earthquake.

A)2
B)10
C)100
D)1000

Question 13

Which of the following correctly lists the order in which seismic waves arrive at a seismograph station?

A)P waves,surface waves,S waves
B)P waves,S waves,surface waves
C)S waves,P waves,surface waves
D)surface waves,P waves,S waves

Question 14

Which of the following types of waves is a compressional sound wave?

A)P waves
B)S waves
C)surface waves
D)all of the above

Question 15

An earthquake's Richter magnitude is based on

A)the amount of energy released during an earthquake.
B)the amount of ground movement caused by seismic waves.
C)the distance between the earthquake and the seismograph station.
D)the observed effects on people and structures.

Question 16

The amount of ground displacement in an earthquake is called the

A)dip.
B)epicenter.
C)focus.
D)(fault)slip.

Question 17

The energy released during a magnitude 8 earthquake is approximately ______ times larger than the energy released during a magnitude 6 earthquake.

A)two
B)10
C)100
D)1000

Question 18

If an earthquake occurred in Seattle,Washington,how long would it take for the first seismic waves to arrive at a seismograph station in Miami,Florida,approximately 5000 kilometers away?

A)approximately 8 seconds
B)approximately 8 minutes
C)approximately 8 hours
D)approximately 8 days

Question 19

Which of the following types of seismic waves are the slowest?

A)P waves
B)S waves
C)surface waves
D)P waves,S waves,and surface waves all travel at the same speed.

Question 20

Which of the following types of seismic waves arrive at a seismograph first?

A)P waves
B)S waves
C)surface waves
D)All of these waves arrive at the same time.

Question 21

Which of the following earthquakes was the largest recorded earthquake?

A)1906 San Francisco,California
B)1960 Chile
C)1923 Tokyo,Japan
D)1976 Tangshan,China

Question 22

Shallow earthquakes,less than 20 km deep,are associated with

A)convergent plate boundaries.
B)transform plate boundaries.
C)divergent plate boundaries.
D)convergent,transform,and divergent plate boundaries.

Question 23

Tsunamis can be generated by

A)undersea earthquakes.
B)the eruption of an oceanic volcano.
C)undersea landslides.
D)undersea earthquakes,the eruption of an oceanic volcano,or undersea landslides.

Question 24

Which of the following measurements collected from seismograph stations gives scientists information regarding the type of faulting that occurred during an earthquake?

A)the amount of slip
B)the amplitude of the ground shaking
C)the first motion of the P waves
D)the time interval between the arrival of the P and S waves

Question 25

How fast do tsunamis travel across the ocean?

A)up to 5 kilometers per hour
B)up to 60 kilometers per hour
C)up to 800 kilometers per hour
D)up to 10,000 kilometers per hour

Question 26

Which of the following statements about tsunamis is false?

A)An early warning system for tsunamis has been developed for the Pacific region.
B)Tsunamis are produced by tidal forces,which is why they are also called tidal waves.
C)Tsunamis can reach heights in excess of 20 meters when they reach the shore.
D)Tsunamis travel slower than P and S waves.

Question 27

Earthquakes that originate at depths greater than 100 km are associated with ______ plate boundaries.

A)convergent
B)transform
C)divergent
D)convergent,divergent,and transform

Question 28

How much warning could a "real-time earthquake warning system" provide before destructive seismic waves arrive?

A)approximately 1 minute
B)approximately 1 hour
C)approximately 1 day
D)approximately 1 week

Question 29

What was the approximate magnitude of the 1994 Northridge earthquake in Los Angeles?

A)magnitude 6
B)magnitude 7
C)magnitude 8
D)magnitude 9

Question 30

Which of the following statements is most accurate?

A)Both seismic hazards and seismic risks can be reduced.
B)Seismic hazards can be reduced,but seismic risks cannot.
C)Seismic risks can be reduced,but seismic hazards cannot.
D)Neither seismic hazards nor seismic risks can be reduced.

Question 31

Which of the following regions has the greatest seismic hazard?

A)central United States
B)northeastern United States
C)southeastern United States
D)western United States

Question 32

Which of the following specifies the level of ground shaking that a structure must be able to withstand?

A)building code
B)elastic rebound
C)intensity scale
D)magnitude scale

Question 33

Which of the following statements about earthquakes is true?

A)Earthquakes can be caused by normal,reverse,and strike-slip faulting.
B)Most earthquakes occur in intraplate settings.
C)S waves travel faster than both P waves and surface waves.
D)The time and location of most major earthquakes can be predicted several days in advance.

Question 34

Which of the following pieces of evidence recently led scientists to propose that great earthquakes occur in Oregon,Washington,and British Columbia every 500 to 600 years?

A)dramatic increases in the number of small (M = 6)earthquakes
B)geologic records of flooded,dead coastal forests
C)groundwater records showing dramatic fluctuations in the water table
D)seismograph records of great earthquakes that were previously underestimated

Question 35

Which of the following statements best describes the current state of earthquake prediction?

A)Scientists can accurately predict the time and location of almost all earthquakes.
B)Scientists can accurately predict the time and location of approximately 50 percent of all earthquakes.
C)Scientists can accurately predict when an earthquake will occur,but not where.
D)Scientists cannot accurately predict most earthquakes.

Question 36

Which of the following countries has the least risk of earthquakes?

A)Australia
B)China
C)Japan
D)United Sates

Question 37

Which of the following events released the most energy?

A)the eruption of Mount St.Helens
B)the explosion of the Hiroshima atomic bomb
C)the 1964 Alaska earthquake
D)All of the above released similar amounts of energy.

Question 38

Which of the following recent earthquakes killed the most people?

A)the 1989 Loma Prieta earthquake,northern California
B)the 1994 Northridge earthquake,southern California
C)the 1995 Kobe earthquake,Japan
D)the 2001 Gujarat earthquake,India

Question 39

What type of faulting would be least likely to occur along the mid-Atlantic ridge?

A)normal faulting
B)reverse faulting
C)strike-slip faulting
D)Normal,reverse,and strike-slip faulting are all likely to occur.

Question 40

What type of fault is the San Andreas fault in California?

A)a normal fault
B)a left-lateral strike-slip fault
C)a reverse fault
D)a right-lateral strike-slip fault

Question 41

The average time between large earthquake events along a fault is known as the ______ interval.

A)seismic
B)hazard
C)fault slip
D)recurrence

Question 42

Rocks subjected to ______ are ______.

A)strain; stressed
B)strain; stretched
C)stress; strained
D)stress; stretched

Question 43

The types of hazards caused by ground shaking are referred to as

A)seismic hazards.
B)secondary hazards.
C)primary hazards.
D)structural hazards.

Question 44

One of the things seismologists look for in a seismically active area for short-term forecasting is

A)the behavior of animals in the vicinity.
B)changes in the fault motion recorded by GPS stations.
C)the amount of time since the last major earthquake.
D)rapid deformation of the ground surface.

Question 45

Whether a building will withstand ground shaking during an earthquake depends on

A)the engineering of the building.
B)the intensity of the ground shaking.
C)the material on which the building was built.
D)the engineering of the building,the intensity of the ground shaking,and the material on which the building was built.

Question 46

Which of the following statements about stress and strain is true?

A)Stress affects all rock types,whereas strain only affects some rock types.
B)Stress and strain both describe the amount of deformation in a rock.
C)Stress is the amount of deformation that occurs in a rock,and strain is the amount of force applied to a rock.
D)Stress is the force that causes rocks to deform or undergo strain.

Question 47

The modified Mercalli intensity scale measures

A)the amount of destruction caused by an earthquake.
B)the amount of slip on a fault plane caused by an earthquake.
C)the amplitude of the surface waves.
D)the type of seismic wave in an earthquake.

Question 48

Fault mechanisms at subduction zones are called

A)megathrusts.
B)reverse thrusts.
C)compressional faults.
D)megafaults.

Question 49

The largest earthquakes occur at

A)transform boundaries.
B)intraplate settings.
C)convergent boundaries.
D)divergent boundaries.

Question 50

In southern California,great earthquakes occur on the San Andreas approximately every ______ years.

A)1 to 2
B)5 to 10
C)25 to 75
D)150 to 300

Question 51

Earthquakes that release large amounts of stored energy during short-lived creep events are termed

A)first motion earthquakes.
B)creep quakes.
C)silent earthquakes.
D)compression earthquakes.

Question 52

The size of an earthquake can be related to fault

A)type.
B)rupture area.
C)length.
D)width.

Question 53

How long was the ground rupture created during the San Francisco earthquake of 1906?

A)4 m
B)40 m
C)400 m
D)4000 m

Question 54

What type of seismic wave causes the most building damage?

A)P waves
B)surface waves
C)S waves
D)All seismic waves cause equal amounts of building damage.

Question 55

The 2004 Sumatra earthquake and tsunami were caused by an earthquake along a ______ fault.

A)normal
B)shear
C)subduction
D)megathrust

Question 56

Shallow,intermediate,and deep focus earthquakes occur at

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

Question 57

The 2004 Sumatra earthquake caused a surface displacement of the ocean floor on the order of

A)10 m.
B)100 m.
C)40 m.
D)400 m.

Question 58

Fires that break out following an earthquake event are considered

A)primary hazards.
B)secondary hazards.
C)structural hazards.
D)indirect hazards.

Question 59

What does the elastic rebound theory explain?

A)how seismographs work
B)how fault lines move
C)how elastic rocks are
D)why earthquakes occur

Question 60

When tensional forces act on a fault plane,they produce

A)reverse faults.
B)normal faults.
C)strike slip faults.
D)compression faults.

Question 61

The number of worldwide earthquakes _________ as the magnitude increases?

A)increases two-fold
B)increases 10-fold
C)decreases two-fold
D)decreases 10-fold

Question 62

The ideal seismograph would have to be located

A)deep underground.
B)under water.
C)on a mountain top.
D)in space.

Question 63

What is the first step in preparing for an impending earthquake according to the Southern California Earthquake Center?

A)take cover near a window
B)create a disaster kit
C)consult a building inspector
D)secure loose items

Question 64

As a rule of thumb aftershocks are typically ____ order(s)of magnitude ____ than the mainshock.

A)1; higher
B)1; lower
C)2; higher
D)2; lower

Question 65

With respect to earthquakes,a building code refers to

A)the design of seismographs.
B)building material.
C)building design.
D)building strength.

Question 66

What is the estimated recurrence interval for a fault line that has a slip rate of 3 cm/year and slips 3 m every time it moves?

A)5 years
B)10 years
C)100 years
D)1000 years

Question 67

The fault mechanism of an earthquake refers to the

A)the character of the fault.
B)the way the rocks deformed during the earthquake.
C)first motion of the fault (push up or down).
D)the movement felt at the seismic station.

Question 68

Modern seismographs can measure displacements the width of a(n)

A)street.
B)hand.
C)hair.
D)atom.

Question 69

Which of the following locations would be most likely to generate an earthquake magnitude 9 or higher?

A)Iceland
B)Hawaii
C)Sumatra
D)United States

Question 70

A telescope is to the astronomer what a(n)______ is to a seismologist.

A)earthquake
B)seismograph
C)seismic wave
D)Richter scale

Question 71

A fault line long-term slip rate of 5 cm/year and slips 2.5 m when it moves.What is the recurrence interval of the fault?

A)10 years
B)50 years
C)100 years
D)1000 years

Question 72

A seismic observatory typically has instruments that measure ______ motion(s).

A)up-down
B)horizontal north-south
C)horizontal east-west
D)up-down,horizontal north-south,and horizontal east-west

Question 73

As the distance to an earthquake increases,

A)the elapsed time before the P waves arrive decreases.
B)the time between the arrival of the P and S waves increases.
C)the amount of ground shaking increases.
D)the time between the arrival of the P and S waves decreases.

Question 74

What should you do during an earthquake?

A)Support yourself next to an exterior wall.
B)Drop,cover,and hold on.
C)Get on top of a table.
D)Get under an architectural façade.

Question 75

Following a mainshock of magnitude 6 one could expect aftershocks as strong as

A)5)
B)6)
C)7)
D)8)

Question 76

Assuming that the elastic rebound theory worked consistently for a given fault,one would expect earthquakes to repeat at fixed time intervals along that fault given a

A)constant slip rate.
B)specific rock type.
C)specific type of fault.
D)certain fault length.

Question 77

A fault line has recurrence interval of 100 years and a long-term slip rate of 5 cm/year.How much does the fault slip when it ruptures?

A)1 cm
B)5 m
C)100 m
D)1000 m

Question 78

Determination of fault mechanism of an earthquake requires that

A)stations are close to the focus.
B)stations are far from the focus.
C)the fault be of a specific type.
D)stations surround the focus.

Question 79

The elastic rebound theory describes

A)how earthquakes bounce off layers.
B)the elasticity of rocks.
C)the flexibility of a fault.
D)how earthquakes recur along an active fault.

Question 80

At what point do we assign a series of earthquakes their categories (i.e.,mainshock,foreshock,or aftershock)?

A)during the foreshocks
B)following the mainshock
C)following the aftershocks
D)before the episode