Deck 10: Earthquakes

Question 1

The loss of life resulting from recent earthquakes in Turkey was a function of the extreme magnitude of the initial earthquake and subsequent aftershocks.

Answer 1

False

Question 2

Earthquakes occur because brittle rocks near earth surface undergo elastic deformation and rebound following rupture.

Answer 2

True

Question 3

Earthquake waves can be recorded because ground motion causes the seismograph to shake.

Answer 3

False

Question 4

Seismic waves are like water waves in that they radiate outward across Earth's surface from the point of disturbance.

Question 5

The focus of most earthquakes is less than 100 km.

Question 6

Earthquakes generated along divergent plate boundaries are typically shallow focus.

Question 7

The majority of earthquakes occur along the circum-Pacific belt and are due to convergent plate activity.

Question 8

The San Andreas fault is not part of the circum-Pacific belt.

Question 9

P-waves cause most of the structural destructive due to earthquakes.

Question 10

Seismographs record both body and surface waves.

Question 11

Earthquake epicenters can be located if seismographs are located within a few hundred km of the earthquake.

Question 12

Prediction of instances of especially high tides is a scientifically accepted method used to predict earthquakes.

Question 13

Earthquake control relies on our ability to redirect Earth stresses to less populated areas.

Question 14

The dilatancy model for earthquake prediction is based on the premise that rocks decrease in volume when subjected to very high pressures.

Question 15

If the frequency of earthquakes can be increased along a fault segment, earthquake magnitude should decrease.

Question 16

Opening of large crevasses is a significant source of danger created by earthquakes.

Question 17

According to the elastic rebound theory

A) rocks will bend before they break.
B) rocks will snap back into their original shape after faulting.
C) rocks will break when their capacity to store energy of deformation has been exceeded.
D) A and C
E) all of the above

Question 18

When an earthquake occurs

A) energy in the form of waves radiates from the point of release
B) deformed rocks rebound releasing energy
C) surface waves produce body waves
D) A and B
E) B and C

Question 19

The angle of dip of a Benioff Zone is a reflection of

A) the presence or absence of a subduction zone.
B) the angle of dip of subducting oceanic crust.
C) the angle of convergence between two descending plates.
D) B and C
E) all of the above

Question 20

An example of one of the strongest earthquakes of intraplate origin known in North America in historical times is

A) the 1906 San Francisco earthquake.
B) the 1964 Anchorage, Alaska earthquake.
C) the 1811 New Madrid, Missouri earthquake.
D) the 1886 Charleston, Carolina earthquake.
E) the 1984 Mount St. Helens, Washington earthquake.

Question 21

How many earthquakes strong enough to be felt by someone are recorded by seismographs each year?

A) 3
B) 30
C) 300
D) 3,000
E) 30,000.

Question 22

Any one type of seismic wave will vary in its actual velocity depending on

A) the length of the route it has taken.
B) the material through which it has traveled.
C) whether it has traveled through Earth or along its surface.
D) the depth of the hypocenter.
E) A and B

Question 23

The magnitude of an earthquake is another term for

A) its intensity.
B) the damage created.
C) the energy released.
D) the duration of trembling.
E) A and C

Question 24

An earthquake of magnitude 7 releases times as much energy as a magnitude 3 earthquake.

A) 10
B) 100
C) 1000
D) 10000

Question 25

According to the dilatancy model of earthquake precursors, immediately prior to the earthquake

A) seismic wave velocity decreases
B) electrical resistivity decreases
C) small seismic events decrease
D) animals move out of their burrows
E) all of the above

Question 26

A successful earthquake prediction must include which of the following parameters?

A) a time-frame for occurrence
B) location
C) strength
D) B and C
E) all of the above

Question 27

The most destructive earthquakes are almost always (shallow-, intermediate-, deep-)___________focus.

Question 28

Seismic waves travel more (slowly, rapidly)___________ through rocks of higher density and more (slowly, rapidly)___________ through rocks of greater elasticity.

Question 29

S-wave velocity is (slower, faster) ___________than that of P-waves and the former can only pass through materials that are (solid, liquid, gas) ___________.

Question 30

Surface waves have velocities that are (faster, slower) ___________than body waves.

Question 31

The___________ of an earthquake on the Richter Scale is determined by measuring the ___________ of the largest seismic wave at a standard distance from the epicenter.

Question 32

The magnitude of an earthquake is measured by the ___________of the largest seismic wave recorded at a distance of ___________from the epicenter.

Question 33

Dipping seismic zones along convergent plate boundaries are known as ___________ ___________.

Question 34

A___________ results from a rapid release of energy in a body of water.

Question 35

What controls whether an earthquake is shallow-, intermediate-, or deep-focus?

Question 36

Why are earthquakes generated at divergent and transform plate boundaries nearly always shallow-focus?

Question 37

Why do so few earthquakes occur within plate interiors and along spreading ridges?

Question 38

What are three possible precursors for earthquakes? Explain their relation to the pending earthquake.

Question 39

What single model of pre-earthquake phenomenon accounts for several of the changes observed prior to many earthquakes?

Question 40

What are the two most important factors determining the amount of damage that can occur in an area during an earthquake as demonstrated again by recent earthquakes in California?

Question 41

Did current building codes in California prevent or mitigate the damage caused by the 1989 Loma Prieta and 1994 Northridge earthquakes? Explain.

Question 42

Who first proposed the elastic rebound theory of earthquakes?

Question 43

What is seismology?

Question 44

Generally, what determines the duration of an earthquake?

Question 45

What is the hypocenter, or focus, of an earthquake?

Question 46

What is the epicenter of an earthquake?

Question 47

Why is elasticity of rocks critical to the elastic rebound theory?

Question 48

What was the focal depth of the strongest earthquake recorded in the United States (1964 Alaska)?

Question 49

What is the relationship, if any, between plate boundaries and earthquakes?

Question 50

What are the two primary types of seismic waves?

Question 51

What are the two types of body waves?

Question 52

What properties of the material through which they pass determine the velocities of P- and S-waves?

Question 53

Which are the fastest seismic waves, which can travel through solids, liquids and gases?

Question 54

Which type of seismic waves cause particles at or near the surface of Earth to vibrate back and forth in a horizontal plane perpendicular to the direction of wave travel.

Question 55

A seismograph records what type(s) of seismic waves (underline all that are applicable): P-waves, S-waves, L-waves, R-waves

Question 56

How much more energy is released for every integer increase of magnitude on the Richter Scale?

Question 57

What was the approximate magnitude of the 1906 San Francisco earthquake?

Question 58

What caused most of the damage in the 1906 San Francisco earthquake?

Question 59

Describe the relation between frequency and magnitude of earthquakes.

Question 60

Explain the relation between frequency and magnitude of earthquakes.

Question 61

Why are Benioff zones inclined or dipping?

Question 62

What are tsunami?

Question 63

What causes tsunami?

Question 64

Why are tsunami so destructive?

Question 65

The disaster movie "The Poseiden Adventure"begins with a cruise liner being overturned by a tsunami. Why could the supposed effect of a tsunami's passage in the open ocean never have occurred?

Question 66

What is the single most important construction modification that should be made to reduce building damage and loss of life from earthquakes?

Question 67

What are four preventive measures that should be taken in constructing new buildings of various types and on various ground materials in regions of high-risk for earthquakes?

Question 68

What is paleoseismology?

Question 69

Where, in North America, do geologists feel there is good evidence for a magnitude 7 or greater earthquake having occurred about 1000 years ago?

Question 70

What is the likelihood of Southern California slipping into the ocean during a giant earthquake in the future?