Exam 3

Question 1

what is the molten rock beneath the earth’s surface called?

Answer 1

magma

Question 2

What is the name for a basaltic lava flow that has a ropy, folded surface?

Answer 2

pahoehoe

Question 3

The eruption of vast quantities of superheated steam is called a ___________

Answer 3

phreatic explosion

Question 4

Which volcanic environment will, on average, produce the most felsic lavas?

Answer 4

continental arc

Question 5

At what boundary within the earth is believed that mantle plumes originate?

Answer 5

mantle-outer core boundary

Question 6

Small vents on volcanoes that emit gas fumes and steam are called_________

Answer 6

fumaroles

Question 7

the amount of ground displacement in an earthquake is called the _________

Answer 7

slip

Question 8

Which plate boundaries are associated with earthquake activity?

Answer 8

convergent, divergent, transform

Question 9

earthquakes that originate at depths greater than 100 kilometers are associated with __________ boundaries

Answer 9

convergent

Question 10

What does the elastic rebound theory describe?

Answer 10

the build up and release of stress during an earthquake

Question 11

What type of seismic wave causes the most building damage?

Answer 11

surface waves

Question 12

the average time between large earthquake events along a fault is known as the _________ interval

Answer 12

recurrence

Question 13

What type of seismic waves are S waves?

Answer 13

shear waves

Question 14

What causes large scale variations in the earth’s geoid?

Answer 14

variations in gravity

Question 15

If the earth’s atmosphere did not contain greenhouse gases, the earth’s surface would be_________

Answer 15

approximately 33 degrees celsius cooler

Question 16

What is the Cryosphere?

Answer 16

ice caps and glaciers

Question 17

What is the earth’s albedo?

Answer 17

the fraction of solar energy reflected by the earth’s surface

Question 18

which of the following do we think has most changed the carbon cycle over the past 150 years?

Answer 18

burning of fossil fuels

Question 19

Which of the following removes carbon from the atmosphere?

Answer 19

photosynthesis

Question 20

The two most common chemical elements in the earth’s atmosphere are _____ and ______

Answer 20

nitrogen and oxygen

Question 21

What is the general process by which rocks are broken down at the earth’s surface?

Answer 21

weathering

Question 22

Which of the following statements about weathering is false?

Answer 22

the presence of soil slows down weathering of the underlying bedrock

Question 23

Which of the following statements about mass movements is false?

Answer 23

mass movements require wind or running water

Question 24

Which of the following forces is the dominant cause of mass movement?

Answer 24

gravity

Question 25

Shallow earthquakes, less than 20 km deep, are associated with ___________.

Answer 25

convergent, divergent, transform

Question 26

What is the approximate distance from the surface to the center of the Earth?

Answer 26

6400 km

Question 27

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

Answer 27

P wave

Question 28

Which of the following statements about the Moho (Mohovoricic discontinuity) is false?

Answer 28

The Moho marks the top of a partially molten layer.

Question 29

What principle is based on the continents being less dense than the underlying mantle?

Answer 29

Isostasy

Question 30

Which layer in the earth does not transmit S waves?

Answer 30

outer core

Question 31

Calculations suggest that the inner core________

Answer 31

spins at a faster rate than the rest of the earth

Question 32

Where is the earth's magnetic field generated?

Answer 32

outer core

Question 33

The Earth's magnetic field shields the surface of the Earth from _________.

Answer 33

solar winds

Question 34

Solidified fragments of volcanic material ejected into the air are called _________.

Answer 34

pyroclasts

Question 35

How many seismograph stations are needed to locate the epicenter of an earthquake?

Answer 35

3

Question 36

The area on the surface of the Earth where P waves and S waves are not recorded by seismograms following an earthquake event are referred to as _______.

Answer 36

shadow zones

Question 37

The Mercalli intensity scale measures ____.

Answer 37

the amount of destruction caused by an earthquake

Question 38

What is a traveltime curve?

Answer 38

graph of travel-time vs. distance

Question 39

Based on seismic tomographic images, how deep do subducting slabs extend?

Answer 39

to the core mantle boundary

Question 40

Which of the following is not a greenhouse gas?

Answer 40

sulfure dioxide

Question 41

Which of the following minerals, present in a granite, is not altered by chemical weathering?

Answer 41

quartz

Question 42

What minerals are responsible for the orange-brown colors of weathered surfaces in the desert?

Answer 42

iron oxides

Question 43

The Milankovitch cycles are dependent on the Earth's ________.

Answer 43

orbital eccentricity, precession, angle of tilt

Question 44

Which of the following minerals is most likely to form a clay mineral during weathering?

Answer 44

feldspar

Question 45

Organic matter in the Earth's topsoil is called ______

Answer 45

humus