MASS WASTING

Question 1

The processes by which rock, soil, or unconsolidated materials move downhill under the influence of gravity are called

Answer 1

mass wasting

Question 2

What is the dominant force that causes mass movement?

Answer 2

GRAVITY

Question 3

Which of the following is not an important factor in causing mass movements?

A. temperature of slope materials
B. nature of slope materials
C. amount of water in materials
D. steepness and instability of slopes

Answer 3

A. temperature of slope materials

Question 4

A hill consisting of loose, dry sand that slopes at the angle of repose and has no vegetation ______.
A. is stable unless oversteepened by excavation
B. may flow if it becomes saturated with water
C. will be more stable if vegetation takes root on the hill
D. all of these

Answer 4

D. all of these

Question 5

Angular pebbles form steeper slopes than coarse sand

Answer 5

TRUE

Question 6

The angle of repose does not depend upon

Answer 6

particle composition

Question 7

situations is most likely to undergo mass wasting?
A. a dry, moderate slope of unconsolidated material
B. a wet, moderate slope of unconsolidated material
C. a dry, steep slope of unconsolidated material
D. a wet, steep slope of unconsolidated material

Answer 7

D. a wet, steep slope of unconsolidated material

Question 8

As the amount of water in a pile of quartz sand increases, the angle of repose will

Answer 8

first increase and then decrease

Question 9

The accumulation of rocks at the base of a cliff is called

Answer 9

TALUS

Question 10

Solifluction occurs in

Answer 10

cold regions

Question 11

Which of the following mass movements is the fastest?

Answer 11

debris avalanche

Question 12

A slow slide of unconsolidated material that travels as a unit is called

Answer 12

SLUMP

Question 13

The most important stress opposing a slope’s shear stress is imparted by:

Answer 13

gravity

Question 14

Water can encourage mass flow by:

Answer 14

reducing friction between grains
undercutting a steep slope
weathering bedrock to clay minerals

Question 15

A talus cone is produced by a:

Answer 15

ROCK SLIDE

Question 16

Loose, uncemented geologic material is said to be

Answer 16

unconsolidated

Question 17

most important factor in causing mass movements?

Answer 17

water content

Question 18

The process by which masses of rock and soil move downhill under the influence of gravity is called

Answer 18

mass wasting

Question 19

One of the most effective ways to stabilize a slope is to

Answer 19

control and remove water

Question 20

The characteristic slope of a pile of dry sand is called the

Answer 20

ANGLE OF REPOSE

Question 21

Damp sand has a higher angle of repose than dry sand because of

Answer 21

surface tension

Question 22

Surface tension is greatest when

Answer 22

sand is moist, but not saturated with water

Question 23

During an earthquake, water-saturated sand can behave like a liquid, a process called

Answer 23

liquefaction

Question 24

Which of the following statements about mudflows is false?

mudflows tend to move slower than debris flows

mudflows are most common in semi-arid regions

mudflows contain large amounts of water

mudflows can carry large boulders

Answer 24

mudflows tend to move slower than debris flows

Question 25

round debris forms steeper slopes than angular debris

Answer 25

FALSE

Question 26

large debris forms steeper slopes than small debris

Answer 26

TRUE

Question 27

dry debris forms steeper slopes than water-saturated debris

Answer 27

TRUE

Question 28

moist debris forms steeper slopes than dry debris

Answer 28

TRUE

Question 29

Which of the following has the steepest angle of repose?

Answer 29

angular quartz pebbles

Question 30

rock types forms the steepest slopes?

Answer 30

granite

Question 31

Which of the following slopes is least stable? a slope where the sedimentary layers dip parallel to the slope a slope where the sedimentary layers are horizontal a slope where the sedimentary layers dip perpendicular to the slope all of these slopes have the same stability

Answer 31

a slope where the sedimentary layers dip parallel to the slope

Question 32

Most of the damage associated with the 1964 Anchorage, Alaska earthquake was caused by

Answer 32

landslides triggered by the earthquake

Question 33

In the cross section above of the upper part of the Grand Canyon, units B and D are most likely composed of

Answer 33

SHALE

Question 34

What is the difference between an earthflow and a debris flow? Earthflows travel faster than a debris flow Earthflows travel slower than a debris flow Earthflows consist of finer material than debris flows Earthflows consist of coarser material than debris flows

Answer 34

Earthflows consist of finer material than debris flows

Question 35

How fast is soil creep? a1 to 10 millimeters per year 1 to 10 meters per year 1 kilometer per hour over 10 kilometers per hour

Answer 35

a1 to 10 millimeters per year

Question 36

Which of the following types of mass movement could a person not outrun?

Answer 36

debris avalanche

Question 37

Why are mudflows and debris avalanches common on volcanic slopes? because there is abundant unconsolidated volcanic ash because earthquakes associated with volcanic eruptions can trigger mass movements volcanic eruptions trigger melting of ice and snow all of these

Answer 37

all of these

Question 38

Solifluction may occur when ________.. the surface layer freezes while the deeper soil remains unfrozen the surface soil layer thaws while the deeper soil remains frozen rapid downhill movement of unconsolidated material moving as unit rapid downhill movement of unconsolidated material moving like a fluid

Answer 38

the surface soil layer thaws while the deeper soil remains frozen

Question 39

only occurs in permafrost regions.

Answer 39

SOLIFLUCTION

Question 40

Why are few mass movement preserved in the geologic record? mass movements have only occurred recently due to human activities mass movement deposits erode easily mass movements were rare in the past due to low rainfall mas movement deposits are destroyed by large animals

Answer 40

mass movement deposits erode easily

Question 41

Mass movements frequently occur at which of the following plate tectonic settings? convergent divergent transform all of the above

Answer 41

all of the above