Mass movement

• What can you name and explain in a karst area?

  Two surface features and two underground features
• What is the focus of the learning intentions in this section?

  Factors, types, and impacts of mass movement
• What is regolith?

  Loose material produced by weathering and erosion
• What causes mass movement?

  Gravity acting on regolith down a slope
• How does gradient affect mass movement?

  Steeper slopes increase the speed of movement
• How does water content influence mass movement?

  Heavier regolith moves downslope faster
• What role does human activity play in mass movement?

  Digging makes slopes steeper and unstable
• How does vegetation affect mass movement?

  Roots bind soil and prevent erosion
• What impact do animals have on mass movement?

  Burrowing loosens soil and exposes it
• What is soil creep?

  Slow movement of soil down a slope
• How can soil creep be identified?

  By angled trees and terracettes formation
• What is a bog burst?

  Movement of saturated peat down a slope
• What causes a bog burst?

  Heavy rainfall saturating the peat
• What are the consequences of a bog burst?

  Blocks roads, damages trees, pollutes water
• What are mudflows?

  Saturated soil and regolith moving like mud
• What speeds can mudflows reach?

  Over 100 kph
• What is a lahar?

  A dangerous mudflow from volcanic activity
• What causes landslides?

  Rapid movement of regolith down unstable slopes
• What factors can trigger landslides?

  Heavy rainfall, earthquakes, and deforestation
• What happened in the June 2017 landslide in China?

  Buried homes and affected many people
• What was the biggest landslide in recorded history?

  Triggered by Mount St Helens in 1980
• What is an avalanche?

  Rapid movement of snow and ice down a slope
• How can mass movement hazards be controlled?

  • Plant vegetation on slopes
  • Cut steps into mountainslopes
  • Restrict overgrazing
  • Use controlled explosions to trigger small avalanches