Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Geography > Mass Movement > Flashcards

Mass Movement Flashcards

1
Q

Define Mass Movement

A

Process by which material moves down a slope under the influence of gravity. The material can include rocks, stones, soil and mud (regolith)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where do landslides occur?

A

Mountainous areas and coastlines

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Do natural processes, tectonic activity or human activity cause solifluction

A

Natural processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How fast can lahars travel on steep slopes?

A

100 km/h

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Do natural processes, tectonic activity or human activity cause slumping?

A

Natural processes and human activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Define human activity

A

Construction, deforestation and road building can increase the risk of mass movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Define gradient

A

The steepness of a slope, affecting how quickly the material moves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What speed is earthflow?

A

Moderate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Causes of earthflow

A
  • Heavy rainfall means water unable to percolate through rock causing soil to be saturated
  • Loses friction with underlying rock and flows downslope
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What speed are avalanches?

A

Fast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Define lahar

A

Volcanic mudflow

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Define water content

A

The amount of water in the soil, which can increase movement by acting as a lubricant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Define soil creep

A

The slow movement of soil down a slope, often causing trees and fences to tilt

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Do natural processes, tectonic activity or human activity cause earthflow?

A

Natural processes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How fast can lahars travel on gentle slopes?

A

20 km/h

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Do natural processes, tectonic activity or human activity cause mudflows?

A

Natural processes and human activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define rockfall

A

The sudden fall of rocks from a steep cliff or slope, usually due to weathering

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Define regolith

A

Loose rock, soil, and debris that covers the earth’s surface

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Do natural processes, tectonic activity or human activity cause lahars?

A

Tectonic activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Do natural processes, tectonic activity or human activity cause bogbursts?

A

Natural processes and human activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Where does soil creep occur?

A

Gentle slops of 10° to 15°

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Where does solifluction occur?

A

Higher ground where soil is frozen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Identify different types of mass movement from diagrams

A

N/A

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What causes soil creep?

A

Freeze thaw action:
* Freezing of land in upland areas
* Soil expands due to water absorption
* Soil contracts when water melts
* Soil moves slowly downslope

Wet dry cycles:

25
Q

Define lahar

A

A destructive mudflow on the slopes of a volcano, often triggered by volcanic activity and heavy rainfall

26
Q

Where does rockfall occur?

A

Very steep/vertical slopes

27
Q

Do natural processes, tectonic activity or human activity cause rockfall?

A

Natural processes and human activity

28
Q

Do natural processes, tectonic activity or human activity cause avalanches

A

Natural processes, human activity and tectonic activity

29
Q

Feature of rockfall

A

Scree fields - largest pieces of scree travel furthest downslope

30
Q

What speed are lahars?

31
Q

What speed is solifluction?

32
Q

What speed is mudflow?

33
Q

Do natural processes, tectonic activity or human activity cause landslides?

A

Natural processes, tectonic activity and human activity

34
Q

What speed are bogbursts?

35
Q

Where and when does earthflow occur?

A

Hills after heavy rainfall where regolith lies over impermeable rock or when forestry removed from hillside

36
Q

Features of earthflow

A
  • Small bulges on landscape
  • Torn vegetation
37
Q

Causes of rockfall

A

Freeze thaw action:
Enlarges cracks and joints, causing pieces of solid rock to break free and fall down slope

38
Q

How fast is soil creep?

A

0.5cm per annum

39
Q

Where does slumping occur?

A

Steep slopes made of unconsolidated material eg. boulder clay

40
Q

Define mudflows

A

Occur when saturated soil and mud flow rapidly down a slope, often after heavy rainfall

41
Q

What speed is soil creep?

42
Q

What speed is rockfall?

43
Q

What effect does vegetation have on mass movement

A

Plant roots help to stabilize the soil and prevent mass movement

44
Q

What speed are landslides?

45
Q

Define landslides

A

A sudden, rapid movement of large amounts of rock and soil down a slope

46
Q

Give details on a lahar case studies

A

Nevado del Ruiz
* Nevado del Ruiz, Colombia erupted on November 13th, 1985 after 69 years of dormancy
* Pyroclastic flows melted the mountains glaciers causing four lahars moving downslope at 50 km/h
* They destroyed the town of Armero, killing 20,000 of its 29,000 inhabitants
* Volcanological organisations had warned the government to evacuate the area two months prior but the government had not listened
* Relief efforts were hindered by the composition of mud which made it difficult to move through

Mt Pinatubo, Philippines, 1991
* Heavy rain mixed with ash deposits from the eruption
* Lahars travelled over 50km destroying everything in their path
* Lahars occured for years after eruptions

47
Q

Features of solifluction

A

Small, thin folds of soil

48
Q

Define avalanche

A

A rapid flow of snow and ice down a mountainside, which can be triggered by weather conditions or human activity

49
Q

What causes solifluction?

A
  • During summer, soil close to surface thaws and soil underneath stays frozen
  • During rainfall, thawed soil becomes water saturated and unable to percolate through permafrost below
  • Moves slowly downslope due to gravity
50
Q

Define bog bursts

A

Happen in upland areas when peat becomes saturated with water and moves downslope quickly

51
Q

Causes of landslides

A
    • Fractures along bedding planes cause rock to dip downward
    • Loose regolith an top slides off
      Water reduces friction between regolith and rock and adds weight causing regolith to move faster downslope
  2. Coastal erosion
  3. Seismic activity
52
Q

Feature of slumping

A

Steep, crescent shaped cliff formed at upper point of slope

53
Q

Define terracettes

A

A series of ridges that run across a hill formed from the slow, downward movement of soil

54
Q

Explain some triggers of lahars

A
  • Volcanic eruptions: Volcanoes have glacial ice at top. Volcanic eruption rapidly melts this ice. Water mixes with volcanic debris
  • Intense rainfall on volcanic deposits: Tropical rainfall (eg. Philippines) mixed with ash - deadly mudflow
  • Collapse of volcanic lake/crater: Sudden release of large amounts of water - mixes with debris
55
Q

Do natural processes, tectonic activity or human activity cause soil creep

A

Natural processes

56
Q

Cause of slumping

A
  • Base of slope removed due to road construction or natural processes at coastlines/riverbanks
  • Causes large block of regolith above it to slide downwards due to gravity
57
Q

Features of soil creep

A
  • Terracettes: Ridges in upper layers of soil - most movement occurs in top soil layer
  • Trees at angles
  • Walls and fences leaning
58
Q

Explain some factors affecting mass movement

A
  • Gradient: The steeper the slope, the faster the material will move due to gravity
  • Water content: Water makes the soil heavier and acts as a lubricant, increasing the likelihood of movement
  • Vegetation: Plant roots help to bind the soil together, reducing the risk of mass movement
  • Human activity: Activities such as deforestation and road construction can destabilize slopes and trigger movement
  • Rock type: Some rocks, like clay, become unstable when wet, leading to increased movement
  • Climate: Areas with heavy rainfall experience more frequent mass movement due to water saturation
59
Q

What speed is slumping?

Geography (12 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions