Chapter 15 Exam (Mass Movements)

The sum of all the underlying causes can push a slope to the brink of failure, and then an immediate cause may trigger the movement. The immediate causes for mass movements include __________.

All of these choices are correct

Clays are the least abundant of all sediments.

False

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Your lord and savior RnB

Before a landslide mass begins to move downhill, it must overcome __________.

inertia and friction

The immediate causes of slope failures, such as earthquakes or heavy rainfall, are called __________.

triggers

The Houston-Galveston, Texas, area has been sinking due to the __________.

withdrawal of groundwater by pumping

External processes that increase the odds of a slope failure include __________.

All of these choices are correct

Many hill-slope masses are weak due to preexisting geologic conditions such as __________.

All of these choices are correct

The natural materials most commonly associated with earth failures are __________.

Clay minerals

A rock at the top of a slope that starts to roll down, it is losing kinetic energy and gaining potential energy.

False

Creep is an ultra-slow, almost imperceptible upslope movement of the soil and lower bedrock zones.

False

Land subsidence is worsened by the cessation of groundwater pumping, because the additional water that is retained underground weakens the rock, making it subside more easily.

False

Quick clays are among the least mobile of all deposits and so provide favorable building sites.

False

The amount of water in pore spaces has no effect on mass movements of earth materials.

False

Water molecules can attach their positive sides against clay minerals because clay surfaces are also positively charged.

False

Which of the following is not true regarding slope failures involving snow?

The density of snow is always the same and so can be ignored when studying avalanches.

Which of the following statements is true regarding submarine mass movements?

There are many different kinds of submarine slope failures and they can cause major problems (e.g., tsunami).

Basal failure surfaces for landslides typically are either curved in a concave-upward sense or nearly planar.

True

Despite what some old movies show, quicksand does not suck people or other objects down.

True

Soils shrink in volume as they thaw, dry, or cool.

True

The main types of mass movement are downward, as in falling or subsiding, or downward and outward, as in sliding and flowing.

True

The orientation of rock layering within a hill can either enhance or hinder the chances of slope failure.

True

The volume of soil does not stay constant but instead swells and shrinks.

True

There are certain times when a hill containing clay minerals is weaker than at other times, and then gravity has a better chance of provoking a slope failure.

True

The Italian city of __________ is trying to save itself from slow subsidence and sea level rise.

Venice

Freshwater passing through uplifted sediments containing quick clay changes the sea salt content leaving quick clay with all but which of the following?

a higher salt content

Catastrophic subsidence into sinkholes tends to occur more often in areas underlain by __________.

acidic freshwater flowing through limestone

Which of the following is a poor choice when trying to reduce the likelihood of a slope failure?

adding water to the slope during a cold snap to freeze it in place

Clay crystals __________________.

are very small

Limestone is dissolved primarily as __________ reacts with water to form a weak acid.

carbon dioxide

If you are alone and get buried deeply in a snow avalanche, you will most likely __________.

die of suffocation

The underlying cause of the Rissa, Norway, landslide was __________.

dissolution of salt in the soil

Of the following types of mass movements, which can move fastest?

rock fall

The sum of the characteristics that hold a mass in place is referred to as __________.

shear resistance

Most of the deaths related to snow avalanches in the United States involve __________.

the elderly taking hikes in the mountains of the Pacific Northwest

The most likely explanation for how highly fluidized rock flows occur is that __________.

the jostling of fragments in the flowing mass provides energy that propagates as trapped sound waves and supports the particles, thus fluidizing the mass (acoustic fluidization)

In __________ masses move down and out by sliding on planes of weakness, such as faults, bedding, or clay-rich layers.

translational slides