Deck 6: Landslides

Question 1

An example of an indirect damaging effect of a landslide is

A) being struck by or buried in debris.
B) flooding upstream of landslide dams.
C) damage of roads in the landslide path.
D) blocked shipping lanes.
E) damage to utilities constructed on the landslide path.

Answer 1

B

Question 2

The Frank slide is Canada's best known landslide and a classic example of

A) a rockfall.
B) a rock avalanche.
C) a debris avalanche.
D) a rockslide.
E) a debris slide.

Answer 2

B

Question 3

The Cordillera Blanca,Peru landslide of 1970,which resulted in 8,000 deaths

A) is best described as a rock avalanche.
B) was triggered by an earthquake.
C) was not in a landslide prone location.
D) occurred during an uncharacteristically prolonged dry spell.
E) occurred at a site characterised by weakly cemented sedimentary rocks with little strength.

Answer 3

B

Question 4

Which of the following is NOT a potential characteristic of a rock avalanche?

A) travel long distances
B) attain speeds of greater than 1000 km/hr
C) override large obstacles in their path
D) can be deadly
E) change into a debris flow

Question 5

Which of the following landslide types involves a flow of wet,deformed soil and weathered rock?

A) rockfall
B) rockslide
C) earthflow
D) slump
E) creep

Question 6

The largest historic slide in Canada is the

A) Frank slide.
B) Hope slide.
C) Saint-Jean-Vianney landslide.
D) Pandemonium Creek landslide.
E) Drynoch landslide.

Question 7

A rotational pattern of slide movement

A) can result in debris avalanches.
B) characteristically produce small topographic benches that tilt upslope.
C) are also called flows.
D) are rarely found in unconsolidated sediment.
E) do not require a plane of weakness.

Question 8

The primary cause of all mass wasting is

A) gravity.
B) oversteepened slopes.
C) rain.
D) human activities.
E) rock/soil type.

Question 9

Liquefaction is a process that

A) requires an earthquake to take place.
B) only occurs in clays.
C) only affects small areas.
D) results in loss of strength within a sediment.
E) caused the Hope landslide.

Question 10

A major environmental and economic issue around the world associated with landslides is the cause-and-effect relationship between

A) increased aridity and rockfall.
B) increased rainfall and erosion.
C) timber harvesting and erosion.
D) road construction and erosion.
E) river migration and mass wasting.

Question 11

Which of the following provinces in Canada is likely prone to the lowest risk from landslides?

A) British Columbia
B) Alberta
C) Saskatchewan
D) Quebec
E) New Brunswick

Question 12

A type of landslide that is common in both humid and arid climates is

A) rock falls.
B) debris flows.
C) shallow soil slips.
D) slumps.
E) deep complex landslides.

Question 13

Landslides are linked to other natural hazards and have been known to trigger

A) earthquakes.
B) wildfires.
C) tsunamis.
D) subsidence.
E) coastal erosion.

Question 14

The factor of safety for a slope can be increased by

A) the addition of water.
B) rising water table.
C) removal of tree roots.
D) decreased cohesion.
E) increased cohesion.

Question 15

The trigger of the Frank slide

A) was an earthquake.
B) was Pleistocene glaciation.
C) was mountain folding.
D) was river erosion.
E) is still debated.

Question 16

Vegetation is a significant factor in slope stability because

A) it provides a protective cover that reduces the impact of falling rain.
B) plant roots reduce cohesion to slope materials.
C) it adds weight to a slope which can decrease the likelihood that the slope will fail.
D) plant roots accelerate surface erosion.
E) plant roots decrease the resistance of a slope to landsliding.

Question 17

A lesson learned from the Frank slide is that

A) large landslides can be prevented.
B) geology is important.
C) human activity does not trigger landslides.
D) another slide at the site cannot now occur.
E) rockfall can be dangerous.

Question 18

Subaqueous (underwater)landslides

A) are characteristically simple events.
B) usually travel short distances.
C) can change into a turbidity currents.
D) cause earthquakes.
E) occur in shallow water.

Question 19

Thaw flow slides would be most common

A) in mountainous regions.
B) during early spring.
C) in areas of permafrost.
D) when the active layer is thin.
E) in winter after a warm spell.

Question 20

Which of the following landslide types can involve failure of rock?

A) debris slide
B) earthflow
C) mudflow
D) slump
E) debris flow

Question 21

Which Canadian province has the greatest number of lawsuits related to landslides?

A) British Columbia
B) Alberta
C) Manitoba
D) Quebec
E) New Brunswick

Question 22

Removing tree roots from a slope will

A) increase the critical shear stress.
B) increase slope friction.
C) decrease the normal stress.
D) decrease slope cohesion.
E) increase the pore pressure.

Question 23

The "quick clays" in the St.Lawrence Valley are

A) soils that developed from deeply weathered bedrock.
B) deposits of fine-grained lake sediments transported from the Great Lakes.
C) surfaces of ancient mudflows.
D) silt and clay originally deposited in sea water.
E) wind-blown silt and clay.

Question 24

What was the most likely trigger for the massive rock avalanche in Frank,Alberta in 1903?

A) heavy melting of snow followed by a drop in temperature
B) an earthquake
C) road building
D) piling heavy rocks at the top of the slope
E) coal mining

Question 25

At the base of a steep rocky headland,ocean wave action

A) deposits sand and stabilizes the cliff face.
B) removes material from the cliff base, decreasing the factor of safety.
C) has no effect on slope stability because wave energy directly reflects back to sea.
D) produces salt spray, which dissolves the rock face and decreases the factor of safety.
E) mixes with loose materials and creates debris flows.

Question 26

Which of the following areas of North America has the lowest landslide risk?

A) British Columbia
B) the Canadian Prairies
C) the Appalachians
D) the U.S. Great Plains
E) the St. Lawrence River Valley

Question 27

The factor of safety is the ratio of

A) material strength to gravity.
B) shear strength to resisting forces.
C) frictional forces to driving forces.
D) resisting forces to driving forces.
E) material strength to frictional forces.

Question 28

Chemical weathering,which decreases rock strength,results from

A) water freezing and thawing in the cracks in rocks.
B) hot water depositing minerals in the cracks in rocks.
C) carbonic acid dissolving rocks.
D) acetic acid dissolving rocks.
E) water dissolving rocks.

Question 29

A large,slow-moving earthflow can be stabilized by

A) covering the surface with permeable gravel.
B) covering the surface with metal mesh.
C) using rock bolts.
D) flooding the toe of the slope.
E) installing drains.

Question 30

Which of the following types of mass movements is the fastest?

A) earthflow
B) rockslide
C) debris flow
D) avalanche
E) rotational slide

Question 31

Climate change is likely to increase the incidence of landslides in some areas in the next century.Which of the following climate-related factors is most likely to increase landslide hazards in a particular area?

A) higher precipitation than today
B) lower precipitation than today
C) warmer temperatures than today
D) cooler temperatures than today
E) higher sea levels than today

Question 32

Which of the following surface features is NOT indicative of a potentially unstable slope?

A) exposed bedrock
B) large boulders at the base of a cliff
C) tongue-shaped masses of sediment at the base of a slope
D) an area of tilted trees
E) crescent-shaped cracks or terraces on a hillside

Question 33

Which of the following factors did NOT play an important role in triggering the Frank Slide in Alberta?

A) rapid snowmelt, infiltration, and freezing with temperature decrease
B) steepening of slope due to erosion by Pleistocene glaciers
C) mining of coal seams deep within the mountain
D) water infiltration of limestones, slowly dissolving carbonates
E) seismic activity induced by mining activities

Question 34

What instruments are used on Mt.Rainier to warn of debris flows and lahars coming off the mountain?

A) rain gauges
B) tiltmeters
C) rock fences
D) global positioning systems
E) acoustic flow monitors

Question 35

Which of the following types of mass movements is the slowest?

A) slump
B) earthflow
C) debris flow
D) creep
E) rock fall

Question 36

Which of the following types of landslides can occur on the seafloor,exclusive of land processes?

A) debris flow
B) rockslide
C) rockfall
D) earthcreep
E) avalanche

Question 37

During a heavy rainstorm,of the following choices,what kind of slope failure would you expect (would be most likely)?

A) debris flow
B) rock avalanche
C) slump
D) rock fall
E) quick clay slide

Question 38

In a slump,material fails

A) along a failure surface that is curved upward.
B) along a failure surface that is curved downward.
C) along a failure surface that is flat.
D) along a vertical failure surface.
E) along a failure surface that is nearly horizontal.

Question 39

In order to keep small rocks from falling onto a road,you would

A) install pipes to drain water out of the slope above the road.
B) install rock bolts to firmly attach the rocks to the slope.
C) install metal mesh over the slope to intercept small rocks.
D) remove all the small rocks from the slope above the road.
E) remove any trees from the slope above the road.

Question 40

If subsurface bedding planes are parallel to a slope surface,and people cut and fill the slope to build housing sites,what type of mass movement is most likely?

A) slump
B) translational slide
C) avalanche
D) rock fall
E) earth flow

Question 41

Colluvium is a mixture of weathered rock and debris below soil.

Question 42

Vegetation adds weight to a slope,which can decrease the likelihood that the slope will fail.

Question 43

Rock fall most commonly occurs during the summer months.

Question 44

A fall and a slide are different names for the same type of landslide.

Question 45

Planes of weakness are especially hazardous if they are parallel to the slope of a hill or mountain.

Question 46

The forces acting on slopes rarely change with time.

Question 47

On average,how many people are killed by landslides in North America each year?

A) 1000
B) 100
C) 30
D) 5
E) 300

Question 48

The term 'creep' is used to describe the flow of rock and/or sediment at rates of

A) several kilometres per year.
B) several hundred kilometres per hour.
C) several metres per hour.
D) a few millimetres to centimetres per year.
E) several metres per second

Question 49

A slump is the same thing as a translational landslide.

Question 50

Landslides do not occur in the low-lying areas of eastern Ontario and southwestern Quebec.

Question 51

The tendency of some flows to rise higher on the outside of a bend in their paths than the inside,is referred to as

A) centripetal flow.
B) slope creep.
C) ascension creep.
D) superelevation.
E) inertial flow.

Question 52

How can landslides provide a natural service function?

A) Clearing areas can increase plant and animal diversity.
B) Landslide dammed lakes provide new fish habitat.
C) Extraction and transportation of valuable minerals from rocks.
D) Attracts and promotes tourism in remote communities.
E) All of the above

Question 53

The Frank Landslide indicated that large landslides cannot be prevented.

Question 54

Shear strength is a force on a slope that resists downslope movement.

Question 55

Which of the following is NOT a common technique for engineering landslide prevention?

A) drainage control
B) construction of dykes
C) removal of unstable slope materials
D) grading of slopes
E) construction of retaining walls

Question 56

Sackung is the rapid downslope movement of a coherent block of rock or sediment.

Question 57

The Frank slide is an excellent example of rock avalanche.

Question 58

The difference between a debris avalanche and a rock avalanche is the type of material involved.

Question 59

For the 1959 Pandemonium Creek landslide in British Columbia,a velocity of 290 km/hr was estimated by

A) acquiring transmission data from sequential cutting of telegraph cables.
B) measuring superelevation data from the run-up zone.
C) first-hand accounts of surveyors monitoring the region.
D) measuring the distance the flow travelled.
E) measuring the scour depth in the source region.

Question 60

The resisting force of the slope material to failure by sliding or flow along potential slip planes,is referred to as the

A) factor of safety.
B) slip factor.
C) shear strength.
D) tensile failure point.
E) friction strength.

Question 61

If a slope has a factor of safety equal to one,it is highly unlikely to fail.

Question 62

Liquefaction can occur without earthquake shaking.

Question 63

The costs of landslide prevention are typically much lower than the costs of damage caused by landslides.

Question 64

Landslides are most common in the Cordillera of British Columbia,Alberta,and the Yukon.

Question 65

Future urbanization is likely to decrease landslide risks.

Question 66

A landslide triggered the most destructive tsunami in Canadian history.

Question 67

The critical shear stress partially depends on pore water pressure.

Question 68

Critical facilities (hospitals,power-generating facilities,fire stations)should be located away from unstable slopes where possible.

Question 69

Urbanization,tree cutting and climate change will increase landslide risk in coming years.

Question 70

A turbidity current occurs under water.

Question 71

Direct effects of landslides include being struck and/or buried in debris and flooding from damming of rivers.

Question 72

A landslide cannot cause a tsunami.

Question 73

Vegetation on a slope is always a stabilizing factor.

Question 74

Adding fill material to the top of the slope will stabilize it.

Question 75

There are no benefits to landslides,as they provide no Natural Service Function.

Question 76

Landslides can cause tsunami.

Question 77

Earthquakes,volcanoes,storms and fires all can cause landslides.

Question 78

Acoustic flow monitors can be used to stabilize a slope prone to landslides.

Question 79

A subsurface layer of clay could be the slip plane of a translational slide.

Question 80

Clearcutting timber on geologically stable land has little influence on landslide-related erosion.