Question 1

What is mass wasting?
A) Recycling of ancient earth materials to make slopes for development
B) Loss of mass from a soil during chemical weathering
C) Downslope movement of rock, soil, and sediment
D) Land lost due to explosive volcanic eruptions
E) Movement of sediment along the coast due to offshore ocean currents

Accepted Answer

Mass wasting, also known as slope movement, is the downslope movement of rock, soil, and sediment. This can occur due to a variety of factors such as gravity, water, and vibrations.

Question 2

Which of the following mass wasting processes does NOT necessarily involve water? A) Earth flow B) Debris flow C) Creep D) Rock fall

Accepted Answer

Rock fall is the only mass wasting process that does not necessarily involve water. Earth flow, debris flow, and creep all involve the presence of water to some extent.

Question 3

Which of the following describes a slump?
A) Rocks break off of cliffs and fall to the base of a slope.
B) Rocks and soil move downslope very slowly.
C) Rapid downslope movement of snow and ice, sometimes with the addition of rock, soil, and vegetation
D) Blocks of rock break off and move together, sliding along a curved path.
E) Mud becomes saturated with water and flows quickly into a streambed.

Accepted Answer

A slump is characterized by the movement of a mass of rock or soil down a slope along a curved surface, which results in the tilting of the slump block away from the slope. This movement is typically more cohesive compared to other types of landslides, with the material moving as a single unit or block.

Question 4

Which of the following is the most rapid form of mass wasting?
A) Rock fall
B) Rock slide
C) Creep
D) Earthflow
E) Slump

Accepted Answer

Rock fall is the most rapid form of mass wasting as it involves the sudden and free fall of rock material from a steep slope or cliff. The rocks can reach speeds of up to 240 km/h and can cause significant damage and danger to people and property below.

Question 5

In which location would you expect to have the most landslides at the END of the given sequence of events? For all areas, assume that each event (drought, wildfire and heavy rain) is identical. A) Location in the mountains that first experiences a long drought, then experiences wildfires, and then experiences heavy rain B) Location in the mountains that first experiences wildfires, then experiences heavy rain, and then experiences a long drought C) Location in the plains that first experiences a long drought, then experiences wildfires, and then experiences heavy rain D) Location in the plains that first experiences wildfires, then experiences heavy rain, and then experiences a long drought

Accepted Answer

The location in the mountains that first experiences a long drought will have dry soil that is more prone to landslides when heavy rain finally comes. Additionally, the wildfires will have likely destroyed vegetation and roots that help hold soil in place, further increasing the likelihood of landslides.

Question 6

Does adding vegetation to a slope make it more or less stable?
A) More stable because the roots will draw water deeper into the ground instead of allowing water to saturate the surface
B) More stable because the vegetation roots will hold together loose soil
C) Less stable because the vegetation adds weight to the slope
D) Less stable because the vegetation will keep more water at the surface of the slope
E) It depends on the slope, adding vegetation could make the slope either more or less stable.

Accepted Answer

The answer of Does adding vegetation to a slope make...

Question 7

Which of the following environments is NOT susceptible to mass wasting? A) A steep and rocky slope B) A moderate slope made of fill materials C) A gentle slope with deep soils D) A slope that has many buildings on it E) Relatively flat-lying area

Accepted Answer

Relatively flat-lying areas are not susceptible to mass wasting because there is no significant slope for gravity to pull materials downhill.

Question 8

Which of the following is the slowest mass wasting process?
A) Avalanche
B) Slump
C) Creep
D) Earth flow
E) Fall

Accepted Answer

Creep is the slowest mass wasting process, as it involves a gradual, almost imperceptible movement of soil and sediment downhill. Other processes like avalanches and falls are more rapid and sudden in nature.

Question 9

Which of the following is the most important driving force in landslide?
A) Weight of the slope in the downslope direction
B) Friction
C) Cohesion
D) Viscosity
E) Shear strength

Accepted Answer

The weight of the slope in the downslope direction is the most important driving force in a landslide, as it directly contributes to the potential for the slope material to move downward due to gravity.

Question 10

Which of the following is NOT a term for a segment type on a slope? A) Free face B) Convex C) Elliptical D) Concave E) Talus

Accepted Answer

Free face, convex, concave, and talus are all terms used to describe segment types on a slope, but elliptical is not.

Question 11

Adding earth material to the lower part of a slope which has the potential for a landslide would
A) increase the resisting force.
B) decrease the resisting force.
C) increase the driving force.
D) decrease the driving force.

Accepted Answer

Adding earth material to the lower part of a slope increases the resisting force by adding mass and support to the slope, which helps to stabilize it and counteract the forces that are pushing the slope material downward.

Question 12

In which location would you expect to have the most landslides? For each area, assume the total amount of rain per year is identical.
A) Mountains with very light rain showers every day
B) Mountains with heavy rainstorms followed by long dry periods
C) Plains with very light rain showers every day
D) Plains with heavy rainstorms followed by long dry periods

Accepted Answer

Mountains with heavy rainstorms followed by long dry periods are more prone to landslides because intense rainfall can quickly saturate the soil, especially on slopes, undermining their stability and leading to landslides. The long dry periods can further destabilize the soil by causing it to crack and lose cohesion, making it more susceptible to movement during heavy rains.

Question 13

If you see a steep cliff with piles of rocks at the bottom, what kind of mass wasting has occurred?
A) Slump
B) Creep
C) Fall
D) Debris flow

Accepted Answer

Fall is the most likely type of mass wasting to occur in this situation. A fall occurs when a block of rock breaks away due to gravity and falls freely through the air before hitting the ground. The piles of rocks at the bottom are evidence of fallen rocks accumulating over time.

Question 14

Which of the following is NOT a way in which water contributes to slope failure? A) Water adds cohesion between the grains of the soil causing it to become unstable. B) Water adds weight to a slope increasing the driving force. C) Water can erode the base of a slope decreasing stability. D) Water can mix with the soil causing debris flows. E) Water can infiltrate slopes causing slumps.

Accepted Answer

Water does not add cohesion between the grains of soil, rather it reduces it by filling the spaces between grains and reducing the intergranular contact force. This makes the soil more susceptible to slope failure.

Question 15

Which of the following statements is FALSE about snow avalanches? A) Snow avalanches are very rare and seldom cause death. B) Snow avalanches can be caused by people. C) The incidence of snow avalanches depends on the temperature of the snow. D) Snow avalanches tend to follow the same paths. E) Snow avalanches require steep slopes of 25° or more.

Accepted Answer

Snow avalanches are not rare and can cause death. In fact, they are a common occurrence in mountainous regions during the winter season.

Question 16

Would adding mass to the top of a slope in the form of houses or buildings make the mass more or less likely to slide?
A) It would make it less likely to slide because the houses would add pressure on the slope keeping it stable.
B) It would make it less likely to slide because the houses make the slope less steep.
C) It would make it more likely to slide because the houses add weight to the slope making it more unstable.
D) It would make it more likely to slide because the houses would make the slope more steep.
E) Adding mass to the top of a slope would not make a difference in the stability of the slope.

Accepted Answer

Adding mass to the top of a slope, such as houses or buildings, increases the weight on the slope, potentially making it more unstable and more likely to slide. This additional weight can exceed the strength of the materials making up the slope, leading to a higher risk of landslides or slope failure.

Question 17

If you see a gently sloping hillside with tilting utility poles, broken retaining walls, and trees with curved tree trunks, what type of mass wasting has probably occurred?
A) Avalanche
B) Slump
C) Creep
D) Earth flow
E) Fall

Accepted Answer

Creep is indicated by slow, gradual downhill movement of soil and vegetation, which can cause tilting utility poles, broken retaining walls, and curved tree trunks.

Question 18

The Portuguese Bend landslide in California involved
A) gradual, continuous, downslope movement over a 30 year time period that resulted in damage to many homes.
B) a volcanic mudflow that killed over 20,000 people despite prior warnings of an imminent landslide threat.
C) an enormous debris slide that created a giant wave which killed ~2,500 people in a matter of a few minutes.
D) heavy rains in an area of folded and fractured limestone bedrock with clay layers and underground caves.

Accepted Answer

The Portuguese Bend landslide, which began in 1956, is characterized by gradual, continuous movement that has caused significant damage to property over the years. It is a classic example of a slow-moving landslide, primarily influenced by factors such as geology, groundwater, and human activities rather than a single catastrophic event.

Question 19

Which of the following involves downslope movement of a coherent, usually large block of earth material along a planar surface?
A) Rock fall
B) Rock slide
C) Creep
D) Earthflow
E) Slump

Accepted Answer

Rock slide involves the movement of rock material down a slope along a planar surface, typically when the rock separates from the bedrock and slides down under the force of gravity.

Question 20

Which of the following is NOT an important factor in the stability of a slope? A) Slope steepness B) Climate C) Direction of Sun exposure D) Vegetation E) Water

Accepted Answer

The direction of sun exposure is not typically considered an important factor in the stability of a slope. The other factors listed (slope steepness, climate, vegetation, and water) all play significant roles in slope stability.

Quiz 7: Mass Wasting

What is mass wasting?

Which of the following mass wasting processes does NOT necessarily involve water?

Which of the following describes a slump?

Which of the following is the most rapid form of mass wasting?

In which location would you expect to have the most landslides at the END of the given sequence of events? For all areas, assume that each event (drought, wildfire and heavy rain) is identical.

Does adding vegetation to a slope make it more or less stable?

Which of the following environments is NOT susceptible to mass wasting?

Which of the following is the slowest mass wasting process?

Which of the following is the most important driving force in landslide?

Which of the following is NOT a term for a segment type on a slope?

Adding earth material to the lower part of a slope which has the potential for a landslide would

In which location would you expect to have the most landslides? For each area, assume the total amount of rain per year is identical.

If you see a steep cliff with piles of rocks at the bottom, what kind of mass wasting has occurred?

Which of the following is NOT a way in which water contributes to slope failure?

Which of the following statements is FALSE about snow avalanches?

Would adding mass to the top of a slope in the form of houses or buildings make the mass more or less likely to slide?

If you see a gently sloping hillside with tilting utility poles, broken retaining walls, and trees with curved tree trunks, what type of mass wasting has probably occurred?

The Portuguese Bend landslide in California involved

Which of the following involves downslope movement of a coherent, usually large block of earth material along a planar surface?

Which of the following is NOT an important factor in the stability of a slope?