Deck 3: Earthquakes

Question 1

How many earthquakes are there every year?

A) About 15
B) About 150
C) About 1,500
D) About 15,000
E) About 1,500,000

Answer 1

E

Question 2

What is the difference between earthquake intensity and magnitude?

A) Only strong earthquakes have intensity; weak earthquakes have magnitude and intensity.
B) Intensity refers to the effects that earthquakes have, magnitude refers to energy released.
C) Intensity refers to energy released and magnitude refers to the effects that earthquakes have.
D) Only weak earthquakes have intensity; strong earthquakes have magnitude and intensity.

Answer 2

B

Question 3

Which seismic waves produce the smallest amplitude?

A) P-waves
B) S-waves
C) Surface waves
D) All seismic waves have the same magnitude.

Answer 3

A

Question 4

In which of the following faults does the hanging wall move down relative to the footwall?

A) Normal fault
B) Reverse fault
C) Thrust fault
D) Blind fault
E) Strike-Slip fault

Question 5

During an earthquake, strain is released and then accumulated again until the next earthquake. This is a statement about the

A) Earthquake cycle.
B) Strain cycle.
C) Richter cycle.
D) Water cycle.
E) Rock cycle.

Question 6

Which of the following is FALSE about slow earthquakes?

A) They are not able to cause damage.
B) They can produce earthquakes with moderate magnitude.
C) They are the result of tectonic creep.
D) They can produce considerable damage to structures.
E) They rupture over long periods of time.

Question 7

Earthquakes are found

A) only on convergent plate boundaries.
B) only on divergent plate boundaries.
C) only on transform fault boundaries.
D) only within tectonic plates.
E) on all plate boundaries and within tectonic plates.

Question 8

Which scale is most useful to describe the absolute size of an earthquake and the energy released during an earthquake?

A) Richter Scale
B) Moment Magnitude Scale
C) Modified Mercalli Scale
D) Fujita Scale
E) Saffir-Simpson Scale

Question 9

Which earthquake scale is based mostly on human opinion and perception of recent events?

A) Richter Scale
B) Moment Magnitude Scale
C) Modified Mercalli Scale
D) Fujita Scale
E) Saffir-Simpson Scale

Question 10

The distance to the epicenter of an earthquake is found by

A) locating the area where most of the damage is centered.
B) comparing the arrival times of the S-and P-waves.
C) comparing the magnitudes of the same seismic wave at different locations.
D) measuring the frequencies of seismic waves at different stations.
E) watching to see where the tsunami forms.

Question 11

Which of the following statements is FALSE about the magnitude of earthquakes?

A) Magnitudes of earthquakes are based on powers of ten.
B) An earthquake of magnitude 3 on the Richter scale involves twice the amount of ground shaking as a magnitude 2 earthquake.
C) Great earthquakes can have a magnitude of 8 or higher.
D) Both the Richter Scale and Moment Magnitude Scale are used to describe the magnitude of an earthquake.

Question 12

Which of the following is TRUE about seismographs taken far from the epicenter of the earthquake as compared to those that are closer?

A) There will not be any P-waves detected.
B) There will not be any S-waves detected.
C) The P and S waves will be closer together.
D) The P and S waves will be farther apart.
E) The amplitude of the waves will be larger.

Question 13

Vibration during an earthquake

A) always results in the development of a cliff at Earth's surface due to movement on a fault.
B) creates large open gashes in the Earth, which can swallow automobiles.
C) causes wet clay to become firmer; thus, when siting a house in an earthquake-prone region, it is best to build it over a landfill containing wet clay.
D) is usually most intense when the surface waves arrive.

Question 14

Which of the following best describes a fault?

A) giant gap or canyon at the Earth's surface
B) cave or large hole hidden under the ground
C) where the continent meets the ocean
D) giant underground chamber usually filled with magma
E) fractured rock that has been displaced, i.e., rocks on one side of the fracture have moved relative to the other side

Question 15

Which seismic waves are the last to reach a seismograph station?

A) P-waves
B) S-waves
C) Surface waves
D) Body waves
E) All seismic waves travel at the same speed and therefore reach any seismograph station at the same time.

Question 16

Which scale is most appropriate to describe earthquake damage to structures and effects on people?

A) Richter Scale
B) Moment Magnitude Scale
C) Modified Mercalli Scale
D) Fujita Scale
E) Saffir-Simpson Scale

Question 17

Vertical movement of rock occurs in all of the following faults EXCEPT

A) normal.
B) reverse.
C) strike-slip.
D) dip-slip.

Question 18

What is a blind fault?

A) Fault that cannot be seen at the surface
B) Inactive fault
C) Fault that is frequently active
D) Fault that is creeping slowly
E) Fault that is not moving

Question 19

According to the elastic rebound model, earthquakes are caused by energy released when

A) highly stressed (i.e.,bent) rock breaks and abruptly moves.
B) asthenosphere is dragged over lithosphere.
C) landslides rumble down the mountain slope.
D) dissolved gases escape violently from molten rock.

Question 20

Which of the following statements is FALSE about P-waves?

A) P-waves are the fastest of the waves.
B) P-waves can move through solid, liquids, or gases.
C) P-waves are a type of compressional wave that moves with a push/pull motion.
D) P-waves cause the most damage in an earthquake.

Question 21

If you knew that an earthquake was coming, where is the safest place to be?

A) In the basement
B) Under a doorway
C) In your backyard away from any buildings or power lines
D) In the garage
E) In your bathtub

Question 22

Which of the following places in the U. S. has the lowest seismic hazard?

A) Seattle, WA
B) St. Louis, MO
C) Los Angeles, CA
D) Minneapolis, MN
E) Charleston, SC

Question 23

Which of the following human activities is NOT known to cause earthquakes?

A) Underground nuclear explosions
B) Injecting liquid waste deep into the ground
C) Building a water reservoir
D) Excavating large amounts of materials to make buildings

Question 24

What causes megathrust earthquakes?

A) Strike-slip faults from subduction
B) Strike-slip faults from a transform plate boundary
C) normal faults at a divergent plate boundary
D) subduction at a convergent plate boundary
E) These are intraplate earthquakes.

Question 25

Mexico City was built on mud deposits. How will this affect the earthquake hazard there?

A) Earthquakes will be dampened there.
B) There will not be any earthquakes there.
C) Earthquakes shaking will be increased.
D) The ground will be susceptible to supershear, which will cause sonic booms that increase damage.
E) There will be more earthquakes due to brittle rupture of the mud.

Question 26

Which of the following is NOT an effect of earthquakes?

A) Ground rupture
B) Liquefaction
C) Volcanoes
D) Fires
E) Disease

Question 27

Which of the following is NOT a reasonable way for communities to deal with the earthquake hazard?

A) retrofit old buildings
B) enact building codes for new construction
C) provide insurance for potential victims
D) educate people on what to do during an earthquake
E) avoid living in an area where there are any earthquakes

Question 28

Which of the following is FALSE about the shaking from earthquakes?

A) Shallow earthquakes tend to cause more ground shaking than deep ones.
B) Places closer to the epicenter experience more ground shaking.
C) The direction that the rupture moves along a fault can affect the amount of shaking.
D) Bedrock causes more ground shaking than mud because the seismic waves are transmitted more efficiently in bedrock.

Question 29

Which kind of material would be prone to liquefaction during an earthquake?

A) Water-saturated sand
B) Dry compacted clay
C) Sedimentary rock with horizontal layering
D) Volcanic rock that is very porous
E) Any earth material (rock or sediment) that is saturated with water

Question 30

Where along a fault are you most likely to see a large earthquake?

A) The area on the fault that has been constantly moving
B) The area on the fault that has not moved in a long time
C) The area on the fault where small and frequent earthquakes are common
D) The area on the fault that has just had a very large earthquake

Question 31

In general, there is more ground shaking from an earthquake with

A) decreasing depth from the surface and decreasing distance to the epicenter.
B) increasing depth from the surface and decreasing distance to the epicenter.
C) increasing depth from the surface and increasing distance to the epicenter.
D) decreasing depth from the surface and increasing distance to the epicenter.

Question 32

Which of the following hazards from an earthquake can threaten areas that may not be close enough to feel shaking?

A) Fires
B) Elevation changes
C) Tsunami
D) Liquefaction
E) Ground rupture

Question 33

Which of the following could threaten an area after the initial shocks from an earthquake subside?

A) Fires
B) Landslides
C) Tsunamis
D) Aftershocks
E) All of the answer choices are correct.

Question 34

What causes earthquakes in San Francisco?

A) Dip-slip faults from subduction
B) Strike-slip faults from a transform plate boundary
C) megathrust earthquakes from a divergent plate boundary
D) megathrust earthquakes from a convergent plate boundary
E) These are intraplate earthquakes.

Question 35

During an earthquake will one side of the fault always rise up relative to the other side?

A) Yes. Earthquakes are always associated with upward movement along the fault.
B) Yes. Earthquakes are always associated with subduction.
C) No. Faults in earthquakes never move up and down.
D) No. Faults in earthquakes sometimes are preceded by ground uplift, but not always.
E) No. Faults that rise up are usually associated with volcanoes and not earthquakes.

Question 36

Strong earthquakes have been felt in Southeast Missouri, what causes these earthquakes?

A) Dip-slip faults from subduction
B) Strike-slip faults from a transform plate boundary
C) megathrust earthquakes from a divergent plate boundary
D) megathrust earthquakes from a convergent plate boundary
E) These are intraplate earthquakes.

Question 37

Which of the following is NOT a reason why building a reservoir would increase earthquakes?

A) Water from the reservoir would add extra weight to existing faults.
B) Water from the reservoir would add extra weight creating new fractures.
C) Water from the reservoir might lubricate existing fractures.
D) Water from the reservoir would lower levels of the groundwater and promote the development of underground caves.

Question 38

If you lived on an active fault and felt a small earthquake, what would that mean?

A) It's a foreshock. A big earthquake is coming.
B) The fault is releasing energy and won't shake again
C) The fault is the type to only cause small earthquakes and there are no worries for big ones.
D) Your fault is becoming more active and more earthquakes are on the way.
E) The fault is releasing energy, but it is not enough to know what might happen next.

Question 39

Which of the following is NOT used to predict an earthquake?

A) Foreshocks
B) Changes in ground elevation
C) Locations of seismic gaps along a fault
D) Gravitational attraction between the Moon and the Earth

Question 40

Which of the following is the most realistic approach to minimizing earthquake hazards?

A) Publicize any prediction and immediately evacuate cities near the earthquake zone
B) Require all new construction to be built on landfill
C) Require any city near a plate boundary to be relocated
D) Bolt together each side of a fault to prevent future earthquakes
E) Legislate strict building codes that require strong and flexible buildings

Question 41

There is 20 times more ground shaking associated with a magnitude 7 earthquake on the Richter scale compared to a magnitude 5 earthquake.

Question 42

Earthquakes can be predicted on a short term basis with considerable accuracy by careful measurement of precursor phenomena such as foreshocks and ground deformation.

Question 43

Whenever there is movement along a fault, an earthquake is felt.

Question 44

P-waves are the fastest seismic waves produced.

Question 45

Earthquake magnitude on the Richter scale is determined by the size of the area damaged from an earthquake.

Question 46

Surface waves are the slowest seismic waves, but they have the largest amplitude and usually cause the most destruction in an earthquake.

Question 47

Blind faults are dangerous because they do not always extend to the surface and thus could be undetected.

Question 48

One of the worst oil spills in U.S. history was when a magnitude 8 earthquake struck near the Alaska pipeline and caused multiple large ruptures.

Question 49

You can determine the location of the epicenter of an earthquake by analyzing seismograph data from any single location.

Question 50

All earthquakes in the U.S. are situated on the West Coast near the San Andreas Fault.

Question 51

Earthquakes are only found along tectonic plate boundaries.

Question 52

Earthquakes may expose new mineral resources for people to mine.

Question 53

Earthquakes along the east coast of the U.S. are generally felt at greater distances from the epicenter tan similar sized earthquakes in California.

Question 54

Earthquakes around the world are extremely common events with an estimated number of more than a million earthquakes every year.

Question 55

There are about 2,000 earthquakes of magnitude 8 or higher every year; fortunately most of them occur in unpopulated areas.

Question 56

Earthquakes are caused exclusively by plate tectonic activity and cannot be caused by human activities.

Question 57

Because Japan is so well prepared for earthquakes, it receives little earthquake damage despite experiencing many earthquakes each year.

Question 58

The San Andreas Fault is considered a potentially active fault because it has not produced a major quake in over 500 years.

Question 59

For earthquakes with a similar magnitude, earthquakes at deep depths tend to cause more damage than shallow earthquakes.

Question 60

Seismic gap refers to a region where no seismic activity ever occurs.

Question 61

Explain the difference between earthquake magnitude and intensity.

Question 62

Areas of the Mississippi Valley located in Southeast Missouri have seen historic earthquakes with magnitudes as great as those in California. Explain why a high magnitude earthquake in this area could cause more widespread disaster than in the west.

Question 63

Explain what a blind thrust fault is and why it is dangerous to those who live near them.

Question 64

Explain how seismologists locate the epicenter of any earthquake.

Question 65

San Francisco, CA is home to many earthquakes. Explain why the area is prone to earthquakes. Much of the area is built on soft wet fine-grained sediment and they have tall buildings. Explain what kinds of hazards earthquakes might have on the region.

Question 66

Earthquake prediction is an area of intense scientific research.

Question 67

The mayor of Peaceful, California (population = 300,000) has asked you to develop a comprehensive plan for earthquake mitigation in her community. During historic times Peaceful, which is located along the San Andreas fault, has experienced a few large, damaging earthquakes and many small earthquakes. Describe several specific measures that you would recommend as part of your mitigation plan.

Question 68

It is possible to develop an earthquake warning system that would provide 15 - 60 seconds of warning to an urban area before the arrival of damaging earthquake waves if the earthquake occurred far enough away.

Question 69

Describe the steps in the earthquake cycle.

Question 70

Not all earthquakes are preceded by foreshocks.

Question 71

Explain how earthquakes may be beneficial to human interests.

Question 72

Explain why fires are associated with earthquakes.

Question 73

The probability of a major flood in any given year is the same whereas the probability of a major earthquake in any given year changes over time. Explain both how and why the probability of a major earthquake changes over time.

Question 74

Explain what steps people should take to prevent personal disaster from a seismically active area.