CHAPTER 12

You can use a landslide hazard map to help buy a piece of property by using it to determine if a. there are large rivers running by the property. b. the property is in a high-risk zone for landslides. c. the property is near a high-risk flood zone. d. the property has been exposed to fires recently

b. the property is in a high-risk zone for landslides

Which of the following types of mass movement often travels as a coherent mass down a curved surface? a. slump b. creep c. rock slide d. mudflow

a. slump

Imagine you have just bought some property and notice that the trees on the slope have curved trunks. What type of landslide event do you likely have on your property? a. liquefaction b. creep c. slump d. mudflow

b. creep

Which of the following types of mass movement takes place most gradually? a. slump b. creep c. rock slide d. mudflow

b. creep

Landforms built by an accumulation of sediment are called ________ landforms. a. erosional b. depositional c. mechanical d. eradication

b. depositional

Slumps typically arrive ____ at the bottom of a slope. a. vertically stacked b. intact c. flattened d. jumbled

b. intact

What type of energy drives plate motion? a. external b. internal c. gravitational d. radiative

b. internal

Some landslides include a mixture of loose sediment and very weathered rock called a. bedrock b. regolith c. solifluction d. substratum

b. regolith

The principal difference between a debris flow and a mudflow is a. the shape of the path taken by the moving mass. b. the grain size of the moving mass. c. that a debris flow contains abundant water, whereas a mudflow is dry. d. that a debris flow contains pyroclastic debris from a volcanic eruption.

b. the grain size of the moving mass

Which of the following is often a sign of mass movement? a. a crack in the ground surface b. water leaking out of a hillside c. new vegetation growth d. flat sloping ground

a. a crack in the ground surface

All of the following are evidence of a recent mass wasting event EXCEPT a. cobble-filled streams b. bowed trees c. head scarps d. piles of loose debris

a. cobble-filled streams

Weathering is a failure trigger because it ______ of the material. a. decreases the cohesion b. increases the friction c. decreases the weight d. takes vegetation off

a. decreases the cohesion

If all else is equal, a slope dipping ___ degrees made of ______ sand would be the most stable situation. a. 30; saturated b. 30; damp c. 30; dry d. 28; saturated

b. 30; damp

Why does adding a small amount of water to a substance increase its cohesion but adding a lot of water decrease its cohesion? a. A small amount of water decreases surface tension, allowing the grains to bond together, whereas too much water will increase surface tension and force the grains away from each other. b. A small amount of water increases surface tension and holds the grains together. Too much water between the grains will eliminate surface tension. c. Water has a small electrostatic force that disrupts the gravitational attraction of the grains and forces them to move away from each other. d. A small amount of water will precipitate cement into the pores of the material, whereas too much water will not allow that cement to form.

b. A small amount of water increases surface tension and holds the grains together. Too much water between the grains will eliminate surface tension.

Which of the following mountains is MOST likely to experience lahars? a. Mount Everest b. Mount St. Helens c. Mount Denali (Mount McKinley) d. The Matterhorn

b. Mount St. Helens

How does water get from the atmosphere into the groundwater system? a. Precipitation falls into rivers and then flows downriver into the groundwater system. b. Precipitation falls on the ground and infiltrates the ground surface to the groundwater system. c. Water from the ocean is sucked up into the groundwater system because of a pressure difference. d. Plants secrete water into the groundwater system in a process called evapotranspiration.

b. Precipitation falls on the ground and infiltrates the ground surface to the groundwater system.

After finishing a new construction project, why is the first task often to install new landscaping around the area? a. The plants will provide nutrients for animals that will carry away the soil. b. The roots will grow into the slope and work to keep the slope intact. c. The plants will add additional weight to the slope and keep it stable. d. The roots take in oxygen and release it into the soil to increase surface tension.

b. The roots will grow into the slope and work to keep the slope intact.

Well-rounded sand has a smaller _____ than irregularly shaped gravel. a. cohesion b. angle of repose c. mineral stability d. cross-sectional area

b. angle of repose

Why do some life activities strengthen the substrate and others weaken it? a. Burrowing creatures distribute stronger soil around, whereas plants digest and weaken soil. b. Burrowing creatures distribute stronger soil around, whereas plant roots wedge soil apart. c. Plant roots help anchor soil, whereas burrowing animals can weaken it. d. Some organisms secrete a binding agent in the soil, whereas plants digest and weaken soil.

c. Plant roots help anchor soil, whereas burrowing animals can weaken it.

Moisture among sediment grains a. always increases the likelihood of mass wasting. b. always decreases the likelihood of mass wasting. c. can promote stability if present in small amounts. d. can promote stability if the grains are saturated.

c. can promote stability if present in small amounts

Which of the following would decrease the resistance force? a. lowering the slope angle b. adding a small amount of water c. chemical weathering of the slope d. adding material to the base of the hill

c. chemical weathering of the slope

Geologists distinguish among different types of mass wasting based on factors such as ______ of the moving material and the rate of movement a. weight b. color c. composition d. name

c. composition

What type of mass movement is an area that shows bowed out tree trunks and misaligned fences? a. rock fall b. mudflow c. creep d. debris slide

c. creep

What type of mass movement is an area that shows bowed out tree trunks and misaligned fences? a. rock fall b. mudflow c. creep d. debris slide

c. creep

Unstable slopes start to move when the _____ force exceeds the ______ force that holds the material in place. a. downslope; gravity b. resistance; downslope c. downslope; resistance d. gravity; resistance

c. downslope; resistance

Which of the following increases the risk of mass movement? a. adding a small amount of moisture to loose, dry sediment b. waves breaking before they reach sea cliffs c. flooding the sediment with water to the point of saturation d. reducing the grade of the slope

c. flooding the sediment with water to the point of saturation

Currents and wind are created by the interaction of _____ and ______ energy. a. internal; external b. internal; gravitational c. gravitational; external d. convective; gravitational

c. gravitational; external

The difference in elevation in an area is called a. erosion b. deposition c. relief d. landform

c. relief

Which of the following consist(s) of large boulders placed at the base of slopes? a. rock dams b. rock sheds c. riprap d. retaining walls

c. riprap

The principal difference between a debris flow and a debris slide is a. the shape of the path taken by the moving mass. b. the grain size of the moving mass. c. that a debris flow contains abundant water, whereas a debris slide is dry. d. that a debris flow contains pyroclastic debris from a volcanic eruption.

c. that a debris flow contains abundant water, whereas a debris slide is dry

Which area would be mostly likely to host a slope failure? a. the coast of Florida b. a desert in central California c. a desert in Arizona d. the coast of southern California

c. the coast of Southern California

Which of the following situations may lead to slope failure? a. the addition of a small amount of water to a slope b. installing a chain-link fence over a slope c. undercutting a slope by a bulldozer d. regrading a steep slope to create a gentler slope

c. undercutting a slope by a bulldozer

Which of the following is NOT an example of a landform? a. mountain b. valley c. water d. swamp

c. water

For dry, fine-grained sediments, the angle repose is typically between ________ and ______ degrees. a. 10; 17 b. 15; 22 c. 20; 27 d. 30; 45

d. 30; 45

Which of the following situations is the most likely candidate for the occurrence of mass movements? a. a flat, desert area with little vegetation b. a gentle slope along the coastline that is across a highway from the surf zone c. gently sloping hills in the tropics d. a mountain terrain in a humid environment

d. a mountain terrain in a humid environment

Which of the following factors decreases the risk of mass movement? a. nearby earthquakes b. excavation into the base of a hill c. adding weight to the top of a hill d. adding vegetation to the side of a hill

d. adding vegetation to the side of the hill

Which of the following landforms would be the result of the subsidence? a. mountain range b. wave-cut terrace c. butte d. basin

d. basin

You are a geologist trying to determine if the slope on which your client's house sits is stable. You determine that the angle of repose of the hillside is 35 degrees. You could consider the slope stable if it is composed of a. saturated sand. b. dry sand. c. saturated gravel. d. dry gravel.

d. dry gravel

The hydrologic cycle can best be described as the a. movement of water through the ground to form aquifers. b. cycle that water passes through when going from solid to liquid to gas. c. circular motion caused by density differences created when water boils. d. movement of Earth's water through a series of reservoirs.

d. movement of Earth's water through a series of reservoirs.

Which of the following types of mass movement is LEAST coherent (most like a fluid)? a. slump b. creep c. rock slide d. mudflow

d. mudflow

Uplift and subsidence are both ultimately the result of a. gravitational resistance b. convectional heating c. external energy d. plate tectonics

d. plate tectonics

Mountain ranges are the result of a. relief b. topography c. subsidence d. uplift

d. uplift

As _____ occurs, intact rock is broken down into smaller, weaker pieces called sediment. a. an avalanche b. cohesion c. solifluction d. weathering

d. weathering