Deck 3: Earthquakes and Their Causes

Question 1

Normal faults are most common near subduction zones.

Answer 1

False

Question 2

The distance to the epicenter is determined by the time delay between the arrival of P and S waves.

Answer 2

True

Question 3

Transform boundaries are most closely associated with reverse thrust faults.

Answer 3

False

Question 4

Stresses cause rocks to deform; earthquakes occur as the rock can no longer deform and ruptures.

Question 5

A 6.0 Richter magnitude earthquake would be expected to produce the most property damage in a(n) ____.

A)intraplate zone
B)subduction zone
C)rift zone
D)transform fault zone
E)induction zone

Question 6

The Mercalli scale uses both subjective and objective measurements of intensity.

Question 7

Earthquakes always occur at plate boundaries.

Question 8

A ____ fault would be expected at a divergent boundary.

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

Question 9

Rock layers that are very susceptible to brittle failure would be expected to produce ____.

A)foreshocks and an earthquake but no aftershocks
B)foreshocks, an earthquake, and aftershocks
C)an earthquake with aftershocks but no foreshocks
D)foreshocks and aftershocks but not a typical earthquake
E)an earthquake without foreshocks or aftershocks

Question 10

The largest earthquakes occur in ____.

A)divergent zones
B)rift zones
C)sand boils
D)subduction zones
E)intraplate zones

Question 11

The first earthquake waves received by a seismograph near the epicenter are P waves.

Question 12

Long fault lines spread out stress and produce smaller earthquakes than short ones.

Question 13

A transform boundary would naturally produce ____ faults.

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

Question 14

The Richter magnitude is determined by measuring the amplitude of wave motion on a seismograph.

Question 15

The Cascadia fault in the Pacific Northwest is currently has ____.

A)a high chance of a catastrophic earthquake with a low chance of tsunamis
B)a high chance of a catastrophic earthquake with a high chance of tsunamis
C)a low chance of catastrophic earthquakes with a high chance of tsunamis
D)a low chance of catastrophic earthquakes with a low chance of tsunamis
E)no chance of a catastrophic earthquake

Question 16

Rock deformation is referred to as ____.

A)strain
B)rupture
C)stress
D)liquefaction
E)elastic rebound

Question 17

Earthquake motion occurs due to rock ____.

A)deformation
B)rupture
C)stress
D)strain
E)elasticity

Question 18

A previously undiscovered fault may be detected in a ____ event.

A)normal thrust
B)reverse thrust
C)liquefaction
D)blind thrust
E)strike-slip

Question 19

You would be at most risk of an earthquake due to a divergent boundary in which metropolitan area of the United States?

A)Seattle, Washington
B)Los Angeles, California
C)Miami, Florida
D)Salt Lake City, Utah
E)St. Louis, Missouri

Question 20

During an earthquake, solid rock produces more shaking and building damage than loose, water-saturated soils.

Question 21

Increased earthquake magnitude above 6.0 would be expected to produce which effect?

A)stronger shaking only
B)increased earthquake duration only
C)increased area of shaking only
D)increased strength, duration, and area of shaking
E)increased duration and area of shaking only

Question 22

Strain in a fault can be released slowly by _______________ if segments of the fault slip slowly and continuously.

Question 23

Which ground material would you expect to produce the most damage as a result of liquefaction?

A)dry clay
B)dry sand
C)wet sand
D)rocky soil
E)exposed bedrock

Question 24

____ waves have the largest amplitude of motion.

A)Compression
B)Shear
C)P
D)S
E)Surface

Question 25

The amount of positive or negative wave motion is referred to as the ____ of the wave.

A)period
B)frequency
C)wavelength
D)intensity
E)amplitude

Question 26

You would be most at risk of danger due to tsunami effects in which metropolitan area of the United States?

A)Miami, Florida
B)Boston, Massachusetts
C)St. Louis, Missouri
D)Seattle, Washington
E)Los Angeles, California.

Question 27

You would be at most risk of an intraplate earthquake in which metropolitan area of the United States?

A)Seattle, Washington
B)Miami, Florida
C)Salt Lake City, Utah
D)St. Louis, Missouri
E)Los Angeles, California

Question 28

Using the Richter magnitude scale, the amplitude of motion in a 7.0 magnitude earthquake is ____ times the motion in a 5.0 magnitude earthquake.

A)1.4
B)2
C)100
D)10
E)32

Question 29

A mud volcano is an effect of ____.

A)blind thrust earthquakes
B)reverse thrust earthquakes
C)liquefaction
D)slips in subsurface bedrock
E)shaking at the border of mountain ranges

Question 30

The distance to an earthquake is found by comparing the arrival time of ____ waves.

A)P and surface
B)S and surface
C)P and shear
D)S and shear
E)P and S

Question 31

In which order would you expect different types of earthquake waves to arrive at a site a distance away from the epicenter?

A)S waves, then P waves, then surface waves
B)S waves, then surface waves, then P waves
C)Surface waves, then P waves, then S waves
D)P waves, then surface waves, then S waves
E)P waves, then S waves, then surface waves

Question 32

Small earthquakes that precede a large earthquake are referred to as _______________.

Question 33

How many separate sites of seismograph recordings are required to locate the center of an earthquake?

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

Question 34

Eastern North American areas such as Missouri are at risk of suffering _______________ earthquakes.

Question 35

Using the Richter magnitude scale, what is the lowest earthquake magnitude where you would expect to encounter significant (but not catastrophic) property damage?

A)2
B)4
C)6
D)8
E)9

Question 36

_______________ refers to the change in rock shape due to stress.

Question 37

Using the Richter magnitude scale, a 3.0 magnitude earthquake releases about ____ times the energy as a 2.0 magnitude earthquake

A)1.5
B)2
C)32
D)10
E)100

Question 38

Which type of waves are called "body waves" because they move through the interior of Earth?

A)P waves only
B)S waves only
C)surface waves only
D)S waves and surface waves
E)S and P waves

Question 39

_______________ faults move rock above the fault up and over rock below with a steep fault surface incline.

Question 40

What is the most critical factor affecting the moment magnitude of an earthquake?

A)shear strength of the displaced rock
B)surface area of the earthquake rupture
C)magnitude of the P and S waves generated
D)seismographic amplitude
E)average slip distance of the fault

Question 41

The _______________ magnitude measures the total energy output of an earthquake.

Question 42

The map point directly above an earthquake's focus is called the _______________.

Question 43

You are located a few dozen kilometers from a magnitude 6.0 earthquake. Describe the sequence and effects that you will experience as a result of the different types of earthquake waves that will pass you.

Question 44

The _______________ scale uses only objective measurements to describe an earthquake's intensity.

Question 45

Describe some of the evidence for a major earthquake on the Cascadia fault around 1700, and the reason why the fault is considered to be extremely dangerous.

Question 46

Describe the key elements of what happens to rock before, during and after an earthquake in the elastic rebound theory.

Question 47

Describe four common types of faults and the key characteristics or motion of each.

Question 48

Earthquakes can cause _______________ in which soil that is ordinarily stable behaves like a fluid.

Question 49

The atomic bomb dropped on the city of Hiroshima, Japan at the close of World War II ("Little Boy") released energy equivalent to 15 kT (about 15 million kilograms of explosive). The largest nuclear weapon ever tested was a 50 MT (about 50 billion kilograms of explosive) weapon ("Tsar Bomba") developed by the Soviet Union in 1961. ​ Discuss the magnitude of an earthquake required to produce energy equivalent to each weapon, the frequency at which such earthquake occur, and differences you might expect in the way nuclear weapons and earthquakes cause harm to a population. Refer to Figure 3-28 in your text, which illustrates t he average number of earthquakes per year, worldwide, and a comparison of the amount of energy they expend.

Question 50

_______________ waves are the last to arrive as the result of an earthquake, producing a rolling motion of the ground.