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B. Mass Movement (i) Explain how precipitation and gradient influence mass movement - Junior Cycle Geography - Question B - 2013
Question B
B. Mass Movement (i) Explain how precipitation and gradient influence mass movement. (ii) Name one type of slow mass movement and describe its effects.
Worked Solution & Example Answer:B. Mass Movement (i) Explain how precipitation and gradient influence mass movement - Junior Cycle Geography - Question B - 2013
Step 1
Explain how precipitation and gradient influence mass movement.
Answer
Precipitation plays a crucial role in mass movement by saturating soil and rock. When rain falls, it can increase the water content in the soil, reducing its cohesiveness and making it more susceptible to sliding. As the soil becomes saturated, it reaches a point known as the 'field capacity' where any additional water leads to increased pore water pressure, ultimately triggering landslides or mudflows.
The gradient or slope of the land also significantly impacts mass movement. A steeper gradient increases the potential energy of materials on the slope. As the angle of the slope increases, the gravitational force acting on the materials increases, making them more likely to move. This interaction between precipitation and gradient can lead to several mass movement phenomena, such as landslides or slumping.
Step 2
Name one type of slow mass movement and describe its effects.
Answer
One type of slow mass movement is soil creep. Soil creep occurs when soil particles gradually move down a slope due to gravitational pull, often aided by freeze-thaw cycles that expand and contract the soil.
Effects of soil creep include:
- Altered Landscape: Soil creep can lead to the gradual tilting of trees and fences as they follow the movement of the soil. This can change the overall landscape and may result in uneven ground.
- Infrastructure Damage: As soil moves slowly, it can undermine foundations and roads, leading to cracks and structural damage over time. This is particularly concerning in areas with significant human development.