Mass Movement

Question 1

Mass Movement

Answer 1

The movement of regolith down a slope in response to the pull of gravity, influenced by natural processes, natural disturbances and human activities

Question 1

Influences: Slope Material

Answer 1

Solid rock, less likely to move, unconsolidated (boulder clay) is more likely

Question 2

Influences: Gradient

Answer 2

Steeper the slope, the more likely for mass movement

Question 3

Influences: water content

Answer 3

More water there is, faster the movement

Question 4

Influences: Vegetation

Answer 4

Slows mass movement, binds soil together and absorbs rainfall

Question 5

Influences:
Tectonic Activity

Answer 5

Can speed up mass movement e.g volcanic, earthquakes

Question 6

Influences:
Human activity

Answer 6

Can speed up m. Movement by weakening the slope e.g deforestation or road building

Question 7

How is m. Movement classified

Answer 7

• Speed it occurs
• Condition of material
• type of material

Question 8

Slow: Soil Creep

Answer 8

Slowest form, soil + regolith moved slowly downhill under influence of gravity

Question 9

What is soil creep influenced by

Answer 9

• Periods of heavy rainfall
• Frost heave

Question 10

Slow: Solifluction

Answer 10

Occurs in high altitudes, underlying layer of permafrost, summer the soil can become saturated, water is unable to percolate in the permafrost layer, saturated soil flows downhill

Question 11

Fast: Bogburst

Answer 11

Peat bogs on slopes, heavy rain after dry weather, plants don’t bind soil together, explosion, peat flows downhill
E.g August 2008 Co. Kerry

Question 12

Fast: Mudflow

Answer 12

Steep slopes, deep soils, impermeable rock, rain heavy, mixes with soil, concrete like substance, 100km per hour

Question 13

Fast: Lahars

Answer 13

Volcanic Mudflows, snow melts due to v. Eruptions, water mixes with lava, ash, soil and rock travelling 100km/h

Question 14

Rapid: Landslides

Answer 14

Mountainous or coastal, rock and debris move downhill, can be caused by natural and human factors

Question 15

Natural factors of landslides

Answer 15

• Rainfall lubricates soil making it easier to move, water adds weight
• Weathering
  Slope material fractured by weathering processes, more likely to move downslope
• Earthquakes
  Vibrations can cause soil to slip downhill

Question 16

Human activities that impact landslides

Answer 16

• Loading
  Heavy materials added increases downward force e.g wind farms or dams
• Deforestation
  Roots can no longer bind soil and stabilise it.
• Mining and quarrying
  Blasts cause vibrations which encourage sliding

Question 17

Rapid: Rock Fall

Answer 17

Heavily influenced by gravity and gradient of slope, loose blocks fall, pile ups are called Talus Slopes, occur due to F. Thaw action, E.quakes, undercutting by rivers and waves, plant root wedging

Question 18

Rapid: Liquefaction

Answer 18

When loose sediment becomes over saturated with water, after heavy 🌧️, rapid melting of ❄️ and 🧊, strong vibrations from high mag. quakes

Question 19

Rapid: Slump Rotational Slide

Answer 19

Slumping occurs where unconsolidated material such as boulder clay slips downward along c. surface Area, crescent shaped cliff forms with abrupt end called scarp at the top of slope.
Material gathered at bottom is called slump

Question 20

Rapid: Avalanche

Answer 20

Rapid slow flow, steep slopes, Jan - Mar, heavy snowfall causes weight gain, snow foundations loosen, Deforestation causes instability, earthquakes too, blasting, artillery

Question 21

Avalanche prediction

Answer 21

Predicting When they can happen using past events
Deliberate start using explosives