Rocks and Weathering: Slope processes

Question 1

General mass movements (4)

Answer 1

Very slow movements (e.g. soil creep)
Fast movements (e.g. avalanches)
Dry movements (e.g. rockfalls)
Very fluid movements (e.g. mudflows)

Question 2

How can the types of processes be classified?

Answer 2

Speed of movement, water content, type of movement, material.

Question 3

Causes of mass movement (3)

Answer 3

Gravity, slope angle and pore pressure

Question 4

How is slope failure caused? (2)

Answer 4

Reduction in shear strength, increase in shear stress.

Question 5

Factors that contribute to increasing shear stress (5)

Answer 5

Undercutting/slope steepening, removal of underlying support, loading of slope, lateral pressure (water in cracks, freezing in cracks, swelling, pressure release), transient stresses (earthquakes).

Question 6

Factors that contribute to reduced shear strength (4)

Answer 6

Weathering effects, changes in pore-water pressure, (changes of structures…), organic effects

Question 7

How can downslope movement be opposed (4)

Answer 7

Friction, cohesive forces, pivoting, vegetation

Question 8

Specific mass movements (4)

Answer 8

Heave, flow, slide, fall

Question 9

4 ways how humans can modify slopes to reduce mass movements

Answer 9

Pinning, netting, grading, deforestation