Geology 131 Study Guide Ch11

Front 1

What is the term for the downslope movement of material under influence of gravity?

Back 1

Mass Wasting

Front 2

What is the term for the slope's resistance to mass wasting?

Back 2

Shear strength

Front 3

What is the term for the steepest angle slope can maintain without collapsing?

Back 3

Angle of Repose

Front 4

What is the term for when slope undergoes constant adjustment to new conditions?

Back 4

Dynamic Equilibrium

Front 5

What is the term for common, rapid mass wasting where material is in freefall?

Back 5

Rockfall

Front 6

What is the term for the accumulation of loose rocks at base of slope?

Back 6

Talus

Front 7

What is the term for mass wasting where moves along 1 or more surfaces of failure?

Back 7

Slide

Front 8

What is the term for mass wasting along curved rupture of surface?

Back 8

Slump

Front 9

What is the term for mass wasting where moves as viscous fluid or by plastic motion?

Back 9

Flow

Front 10

What is the term for the complex movement that begins as fall and continues as flow?

Back 10

Debris Avalanche

Front 11

What is the term for the mass wasting involving more than one kind of movement?

Back 11

Complex movement

Front 12

What is the term for material removed from upper slope is used to brace lower slope?

Back 12

Cut and Fill

Front 13

What is the term for the large steps cut into hillside to reduce its chance of failure?

Back 13

Benching

Front 14

What is the term for when unstable rock is fastened to underlying stable bedrock?

Back 14

Rock Bolts

Front 15

What is the term for any kind of mass movement that affects people?

Back 15

Landslide

Front 16

List the 4 features that a slope's shear strength depends on:

Back 16

1. internal friction between grains
2. external support of the slope
3. the slope material's strength
4. the slope material's cohesion

Front 17

List the 3 ways that water influences slope stability?

Back 17

1. Decreasing friction
2. Increasing the cohesion/or
3. Increasing the weight

Front 18

In what type of climates is creep most effective?

Back 18

Creep is most effective in HUMID CLIMATES

Front 19

T or F
Creep can only sometimes be:
1. controlled or
2. stabilized or
3. slowed.

Back 19

True

Front 20

Why is creep difficult to recognize?

Back 20

Because of its SLOW RATE

Front 21

What are the catastrophic results of fast mass movements?

Back 21

1. Loss of life
2. Loss of property

Front 22

Slow mass movements cause major damage to what, life and/or property?

Back 22

Slow mass movements cause major damage to PROPERTY

Front 23

List the 3 ways flows are classified?

Back 23

1. Their speed
2. Type of movement
3. Amount of water

Front 24

Why does road construction frequently trigger mass wasting?

Back 24

Excavation OVERSTEEPENS the slope

Front 25

T or F
All slopes are in dynamic equilibrium.

Back 25

TRUE

Front 26

What happens if humans change slopes?

Back 26

Slopes will change

Front 27

List the 2 features of slopes ;that exceed the angle of repose:

Back 27

1. the slopes fail or
2. the slopes are made of unweathered solid rock

Front 28

In what type of weathering zone, thin or thick is mass wasting more likely?

Back 28

thick weathering zone

Front 29

In what type of slope is mass wasting more likely to occurr?

Back 29

STEEP slope

Front 30

In what type of rocks is mass wasting more likely to occurr?

Back 30

Rocks that have lots of CLAY minerals

Front 31

What are the 3 physical features that cause oversteepening by undercutting?

Back 31

1. streams
2. waves
3. road building

Front 32

Why is weathering a major factor in mass wasting?

Back 32

Because weathering reduces the rock's shear strength.

Front 33

T or F
Vegetation causes soil to lose stability.

Back 33

FALSE

Front 34

What are the 2 influences on slope that vegetation provide?

Back 34

1. Increase the slope's resisting force
2. Decrease the amount of water in a slope

Front 35

List the 4 characteristics of rockfalls?

Back 35

1. Rockfalls are common and rapid
2. Rockfalls are frequently triggered by earthquakes
3. Rockfalls are often the result of frost wedging
4. Rockfalls are the result of failure along bedding planes or joints.

Front 36

Of the following, which is the fastest and least viscous type of mass movement:
A. Earthflow
B. Solifluction
C. Mudflow
D. Creep
E. Deformational Flow

Back 36

C. Mudflow

Front 37

List 4 areas susceptible to, or that have experienced mass wasting:

Back 37

1. Scarps or open fissures
2. Bedding planes parallel to the slope
3. A Hummocky surface
4. Old landslide deposits

Front 38

What is a very effective way to reduce the chance of slope failure?

Back 38

Reduce the amount of water in the slope

Front 39

In what type of situation would rock bolts be an effective landslide mitigation?

Back 39

Granite cut by fractures near the surface

Front 40

What is classification of mass wasting based on?

Back 40

Type of movement

Front 41

Why does landslick risk increases for increasing slop?

Back 41

The gravitation component parallel to the slope increases

Front 42

List the 4 reasons why coastal California is at great risk for mass wasting?

Back 42

1. California is subject to frequent earthquakes
2. California waves undermine cliffs
3. California has frequent brushfires that remove vegetation
4. California's population is high so people build on unstable slopes

Front 43

How does talus form?

Back 43

Rockfalls

Front 44

List the 4 reasons why Turtle Mountain was a dangerous situation?

Back 44

1. Joints were parallel to the slope
2. the area contained unstable clay-rich rocks
3. humans removed coal
4. the slope was steep

Front 45

What are quick clays?

Back 45

Clays that flow when disturbed

Front 46

List the 4 factors that shape the EArth's landscape:

Back 46

1. plate tectonics
2. erosion
3. weathering
4. rock type

Front 47

What effect do fires have on the chance of mass wasting?

Back 47

Fires INCREASE the chance of mass wasting

Front 48

Why do fires increase the chance of mass wasting?

Back 48

Vegetation stabilizes slopes and when there is a loss of vegetation, there is an increase in the chance of mass wasting.

Front 49

What 4 events may trigger mass wasting?

Back 49

1. Loud thunder
2. Intense precipitation
3. EArthquakes
4. Volcanic eruptions

Front 50

T or F
Slow mass movements include solifluction.

Back 50

True

Front 51

Why was the Alaskan pipeline built above the ground in some areas?

Back 51

The Danger of solifluction

Front 52

T or F
Slopes in dynamic equilibrium adjust to new conditions.

Back 52

TRUE

Front 53

T or F
Slope in dynamic equilibrium are balanced so they won't fail.

Back 53

FALSE

Front 54

T or F
Slopes in dynamic equilibrium can slide but not flow.

Back 54

FALSE

Front 55

T or F
Slopes in dynamic equilibrium have resisting forces equal to gravitational forces so are stable.

Back 55

FALSE

Front 56

T or F
Slopes in dynamic equilbrium are in constant motion.

Back 56

FALSE

Front 57

What are the 4 reasons why California have mass wasting events every FAll-Winter?

Back 57

1. Summer fires destroy vegetation
2. Fall-Winter rains decrease slope shear strength
3. it is tectonically active so has steep slopes
4. many areas are built on poorly consolidated sediments.

Front 58

What are the 4 possible results of overloading a slope

Back 58

1. increases the driving force of gravity by increasing the weight
2. occurs naturally during volcanic eruptions
3. is usually the result of human activity
4. decreases shear strength

Front 59

What are the 2 main reasons why mass wasting events are difficult to classify?

Back 59

1. they often change behaviors as they move
2. they are frequently combinations of different types

Front 60

How does a slide differ from a fall?

Back 60

The falling material con go very fast because it is in freefall.

Front 61

Up to what percentage of water are mudflows?

Back 61

Up to 30% water

Front 62

List the 4 characteristics of the 1970 debris avalanche that destroyed Yungay and Ranrahiraca Peru?

Back 62

1. Started as a fall
2. Was triggered by an earthquake
3. Moved a huge amount of material
4. Traveled very fast

Front 63

T or F
Mass wasting hazard assessment studies are needed in both mountainous and flat areas.

Back 63

True

Front 64

How do retaining wall increase shear strength?

Back 64

Retaining walls increase base support

Front 65

What are the 2 reasons why draining water helps to stabilize slopes?

Back 65

1. Water reduces a rocks shear strength
2. Water promotes the growth of vegetation

Front 66

T or F
The fastest types of mass wasting usually do the most property damage.

Back 66

FALSE

Front 67

T or F
Slopes that lie at less than their angle of repose never experience mass wasting.

Back 67

FALSE

Front 68

T or F
Overloading of a slope is usually the result of human activity.

Back 68

TRUE

Front 69

T or F
Mass movements commonly begin as one type of movement and change into another as they move.

Back 69

True

Front 70

T or F
Flows often begin as falls, slumps, or slides.

Back 70

TRUE

Front 71

T or f
Since engineers are battling gravity when stabilizing slopes, landslide prevention is temporary.

Back 71

TRUE

Front 72

T or F
The US spends only a few million dollars on mass wasting annually.

Back 72

FALSE

Front 73

T or F
Slope failure occurs when the gravitational force exceeds the slope's shear strength.

Back 73

TRUE

Front 74

T or F
Benching is frequently used to reduce the mass wasting hazards along roadcuts.

Back 74

TRUE

Front 75

T or F
Entire cities and hundreds of thousands of people may be destroyed by a single mass wasting event.

Back 75

TRUE