Chapter 15

Front 1

Before a landslide mass begins to move downhill, it must overcome __________________.
A. gravity and friction
B. inertia and gravity
C. inertia and friction
D. gravity and creep

Back 1

Inertia and friction

Front 2

Swelling of soil is caused by all but which of the following?
A. freezing soil with a high percentage of void space or porosity
B. wetting of soil rich in clay minerals
C. heating by the Sun
D. wetting a soil composed of quartz sand

Back 2

Wetting a soil composed of quartz sand

Front 3

External processes that increase the odds of a slope failure include __________________.
A. adding mass high on a slope, as in sediment deposition
B. steepening the slope, as by fault movements
C. removing support from low on a slope, as by stream or ocean-wave erosion
D. All of these are correct.

Back 3

All of these are correct

Front 4

Internal causes of slope failure include all but which of the following?
A. inherently weak materials
B. water in different roles
C. increasing cohesion
D. adverse geologic structures
E. pre-existing faults

Back 4

increasing cohesion

Front 5

The materials most commonly associated with earth failures are ________________.
A. clay minerals
B. quartz
C. granite
D. basalt
E. pahoehoe

Back 5

clay minerals

Front 6

The bulk chemical compositions of feldspars and clays are _________________.
A. similar, but their internal structures are radically different
B. radically different, but their internal structures are similar
C. similar, as are their internal structures
D. very different, as are their internal structures

Back 6

similar, but their internal structures are radically different

Front 7

Clay crystals ____________________.
A. are very large
B. are very small
C. range from very large to very small
D. are amorphous
E. form isostacies

Back 7

are very small

Front 8

Clay minerals may have their strength lessened by water ___________________.
A. adsorbed to the exterior of clays, thus spreading the grains apart
B. absorbed between the interlayer sheets, with resultant expansion
C. Both adsorbed to the exterior of clays, thus spreading the grains apart and absorbed between the interlayer sheets, with resultant expansion are correct.
D. Neither adsorbed to the exterior of clays, thus spreading the grains apart nor absorbed between the interlayer sheets, with resultant expansion is correct.

Back 8

Both adsorbed to the exterior of clays, thus spreading the grains apart and absorbed between the interlayer sheets, with resultant expansion are correct.

Front 9

Freshwater passing through uplifted sediments containing quick clay changes the sea salt content leaving quick clay with all but which of the following?
A. weak structure
B. grains mostly less than 0.002 mm diameter
C. water contents commonly in excess of 50 percent
D. a high salt content
E. All of these are correct.

Back 9

A high salt content

Front 10

Water weakens earth materials in which of the following ways?
A. through interplay with clay minerals
B. decreasing the cohesion of rocks
C. aiding subsurface erosion
D. increasing pressure in pores of rocks and sediments
E. All of these are correct

Back 10

all of these are correct

Front 11

The underlying cause of the Rissa, Norway, landslide was ________________.
A. dissolution of salt in the soil
B. too much gypsum in the soil
C. over-steepening of slopes of volcanic ash
D. freezing and thawing of piles of glacial boulders
E. layering of volcanic pyroclasts

Back 11

dissolution of salt in the soil

Front 12

In California on 12 March 1928, the St. Francis dam failed, unleashing a 185-ft-high wall of water moving 18 mph that killed about 420 people. This was caused by _______________________.
A. dissolution of gypsum cement holding the dam's foundation rock together
B. an earthquake nearby
C. liquefaction of clay in the dam itself
D. erosive flow through a crack in the concrete dam
E. A combination of all of these are correct.

Back 12

dissolution of gypsum cement holding the dam's foundation rock together

Front 13

Many hill-slope masses are weak due to preexisting geologic conditions such as _________________.
A. ancient slide surfaces
B. rock layering dipping less than topographic slopes
C. structures within the rocks, such as fractures, ancient faults, and thin clay seams
D. All of these are correct.

Back 13

All of these are correct

Front 14

The Vaiont dam disaster in Italy in 1963 was caused by _______________________.
A. Sedimentary rock layers folded into a trough-like configuration (syncline) with daylighted beds on each side of the river valley
B. water filling the reservoir and saturating the rocks at the top of the slopes, causing elevated pore-water pressures
C. the presence of old slide surfaces in the rocks, along with some rock layers containing thin seams of weak clays
D. limestone in the hills with numerous caverns dissolved into it
E. All of these are correct

Back 14

All of these are correct

Front 15

Humans can cause landslides to occur by ________________________.
A. adding fill dirt high on hill slopes to improve the view, thus adding to the driving mass.
B. removing material from the base of a slope to widen or clear a road or to form a building lot, thus weakening the resisting mass.
C. Both of these are correct.
D. Neither of these are correct.

Back 15

Both of these are correct

Front 16

Rocks have weaknesses that set up slope failure where __________________.
A. rocks are not cemented together
B. a clay layer may provide a basal slip surface
C. soft rock layers may slide off strong materials
D. joints split and separate rock
E. All of these are correct.

Back 16

All of these are correct

Front 17

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. Triggers for mass movements include ________________.
A. heavy rains
B. earthquakes
C. thawing of frozen ground
D. the construction projects of humans
E. All of these are correct.

Back 17

All of these are correct

Front 18

In Yosemite National Park in July 1996, a 162,000-ton mass of granite pulled away from a canyon wall and slid down 540 ft, then launched into the air for a 1640-ft drop in an arcing trajectory, reaching a speed of 270 mph before hitting the valley floor. This event would best be classified as ________________.
A. subsidence
B. a rotational slide
C. a flank collapse
D. a fall
E. a slick-n-slide

Back 18

A fall

Front 19

. In __________________, masses move down and out by sliding on planes of weakness, such as faults, bedding, or clay rich layers.
A. rock falls
B. translational slides
C. rotational slides
D. debris flows
E. struzstroms

Back 19

translational slides

Front 20

Translational slide masses behave in all but which of these different fashions?
A. They may remain basically coherent as block slides.
B. The sliding mass may deform and disintegrate to form a debris slide.
C. Lateral spreading may occur where the underlying material fails and flows, thus causing the overlying coherent material to break apart and move.
D. They fall vertically into sinkholes.

Back 20

They fall vertically into sinkholes.

Front 21

Of the following types of mass movements, which can move fastest?
A. creep
B. translational rockslide
C. avalanche
D. mudflow
E. earth flow

Back 21

avalanche

Front 22

The stability of a hillslope is improved by __________________.
A. increasing pore water pressure
B. decreasing the weight of hillslope materials
C. steepening the slope
D. removing roots and ground plants
E. dissolving the cement between soil or rock grains

Back 22

decreasing the weight of hillslope materials

Front 23

The Houston-Galveston, Texas, area has been sinking. This is related to the _________________.
A. withdrawal of groundwater by pumping
B. dissolution of limestones
C. emptying of a magma chamber
D. weight of all the high-rise buildings and houses
E. dissolution of a salt layer

Back 23

withdrawal of groundwater by pumping

Front 24

The land beneath Mexico City is sinking because of ___________________.
A. volcanic activity
B. earthquakes
C. groundwater withdrawal
D. tectonic rifting
E. pumping of oil wells

Back 24

groundwater withdrawal

Front 25

The Italian city of ____________ is trying to save itself from slow subsidence and sea level rise.
A. Rome
B. Florence
C. Turin
D. Pisa
E. Venice

Back 25

Venice

Front 26

Catastrophic subsidence into sinkholes tends to occur more often in areas underlain by _______________.
A. limestones
B. sandstones
C. shales
D. granite
E. hot-spot volcanoes

Back 26

Limestones

Front 27

Catastrophic subsidence into sinkholes tends to occur more often in areas underlain by __________________.
A. acidic freshwater flowing through limestone
B. basic freshwater flowing through limestone
C. acidic saltwater flowing through sandstone
D. basic freshwater flowing through sandstone
E. basic saltwater flowing through sandstone

Back 27

acidic freshwater flowing through limestone

Front 28

Liquefaction can occur by which of the following processes?
A. increase of surface tension
B. carbon-carbon bonding
C. breaking surface tension and rearranging grains
D. radioactive decay

Back 28

breaking surface tension and rearranging grains

Front 29

The most likely explanation for how highly fluidized rock flows occur is that __________________.
A. 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)
B. water lubricates the material, allowing it to flow (hydro fluidization)
C. steam lubricates the material, allowing it to flow (aqueous fluidization)
D. the flowing mass rides on a cushion of compressed air (jetting)
E. heat generated by friction melts material within the mass, allowing it to flow (thermal fluidization)

Back 29

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)