Deck 13: Earthquakes and Earth Structure

Question 1

-Point A, where slip initiated during the earthquake, is called the __________.

A) dip
B) epicenter
C) focus
D) strike

Answer 1

C

Question 2

-Point B is called the earthquake __________.

A) dip
B) epicenter
C) focus
D) strike

Answer 2

B

Question 3

Where does slip initiate during an earthquake?

A) epicenter
B) focus
C) strike

Answer 3

B

Question 4

-What causes the up-and-down wiggles on the seismogram?

A) electromagnetic pulses
B) tsunami waves
C) ground vibrations
D) variations in air pressure

Question 5

-Which set(s) of waves travels through the Earth's interior?

A) set A
B) set B
C) sets A and B
D) sets A, B, and C

Question 6

-Which set(s) of waves is/are most likely surface waves?

A) set A
B) set B
C) set C
D) Sets A, B, and C are all surface waves.

Question 7

What is the moment magnitude of an earthquake proportional to?

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

Question 8

What type of machine records the seismic waves generated by earthquakes?

A) gravimeter
B) compass
C) seismograph

Question 9

At a seismograph station, what type of seismic waves arrive before the surface waves?

A) P waves but not S waves
B) S waves but not P waves
C) both P waves and S waves

Question 10

What type of information can be gained by examining the first motion (push or pull) of P waves arriving at different seismograph stations?

A) moment magnitude
B) type of faulting
C) amount of slip

Question 11

For two earthquakes located the same distance away, the ground shaking produced by a Richter magnitude 4 earthquake would be ___ times greater than the ground shaking produced by a magnitude 3 earthquake.

A) 1.33
B) 4
C) 10

Question 12

About how often do magnitude 8 earthquakes occur?

A) twice a year
B) once every 3 years
C) once every 30 to 100 years

Question 13

-What type of seismic wave is depicted by the ray path in the diagram?

A) a P wave
B) an S wave
C) a surface wave
D) all of the above

Question 14

-The two kinks in the seismic wave path are examples of seismic __________.

A) isostasy
B) reflection
C) refraction
D) tomography

Question 15

What causes the sharp increases in the velocity of S waves at 400 and 670 kilometers depth in the mantle?

A) changes in the composition of the mantle
B) changes in the mineral structures
C) changes in the pressure of the mantle
D) changes in the temperature of the mantle

Question 16

The S wave shadow zone is caused by the

A) inner core.
B) lower mantle.
C) outer core.

Question 17

P waves travel through peridotite at about ___ km/s.

A) 4
B) 6
C) 8

Question 18

The following question refers to the cross section of the Earth in the following figure.

-Which region of the Earth does not transmit S waves?

A) region A
B) region B
C) region C

Question 19

Seismic tomography can detect relatively warm regions of the mantle because S waves

A) do not pass through these regions.
B) travel more slowly through these regions.
C) travel more rapidly through these regions.