Geology Chapter 12 MG – Flashcards
Unlock all answers in this set
Unlock answersquestion
Which of the following describes the curved path of seismic waves through the mantle?
answer
Waves are concave up because rock density increases with depth.
question
How do waves refract in rocks?
answer
Waves refract toward the boundary when moving from less to more dense material. Waves refract away from the boundary when moving from ore to less dense material.
question
Why does a shadow zone occur for P-waves?
answer
P-waves refract as they go through the outer core.
question
Which of the following behaviors of seismic waves help scientists determine the location of layers in the Earth?
answer
Waves stopping (truncating), refracting (bending), reflecting (bouncing).
question
Which of the following layers consist of mostly solid material?
answer
Asthenosphere, lithosphere, mantle, inner core.
question
Which of the following best describes the trend in the speed of seismic waves as they travel toward the center of the earth?
answer
Speeds both increase and decrease as a seismic wave moves toward the center of the earth.
question
Which of the following statements accurately describes P and S-waves.
answer
S-waves do not travel through the outer core whereas P-waves do.
question
Approximately how fast do P-waves travel through the mantle.
answer
13 km/s
question
Approximately how fast do S-waves travel through the outer core?
answer
0km/s - S-waves do not travel through the outer core.
question
Which layer of the Earth makes up more than 82% of the volume of the planet?
answer
Mantle
question
The _____ is a seismic boundary between the crust and the mantle where there is a dramatic increase in seismic wave velocity.
answer
Moho Boundary
question
Which of the following describes the trend of the Earth's temperature (based on the geotherm) moving toward the center of the Earth?
answer
Temperature increases with increasing depth but at different rates.
question
Which of the following describes the relationship between the geotherm and the iron melting curve?
answer
Most rocks are cooler than the melting temperature of iron.
question
What does the iron melting curve tell us about the state of rocks in the Earth?
answer
When the iron melting curve is to the left of the geotherm, rocks are molten. When the iron melting curve is to the right of the geotherm, rocks are solid.
question
Which of the following layers contains mostly molten or liquid rock?
answer
Outer core
question
Which of the following statements describes the relationship between the strengths or rocks and how close the temperature is to the melting point of iron?
answer
Rocks that are warm, or close to the melting point of iron, are weak. Rocks that are cold, or further away from the melting point of iron, are strong.
