Mass Wasting-
It refers to transfer the mass of rock debris down the slopes under the direct influence of gravity.
The movements of mass can be slow as well as rapid.
Causes of mass movements-
- overloading due to heavy rainfall.
- Removal of underlying support from the rocks.
- Occurrence of earthquakes, explosions etc.
- Heavy flow of water from lakes, reservoirs and rivers leading to slow outflow of water from under the slopes or river banks.
- Heavy rainfall in any area.
- Increase in gradient and height of slopes etc.
Types of Mass wasting-
Rockfall and debris fall-
- When a groups or sheets of rock falls freely from a cliff face it is called as rockfall or rock-fall .
- Debris falls are similar to rockfall except that they involve a mixture of soil, regolith, vegetation and rocks.
Rockslide and debris slide-
- A rockslide is a type of landslide caused by rock failure in which part of the bedding plane of failure passes through compacted rock and material collapses en masse and not in individual block.
- Debris slide is also similar to it but it involve a mixture of soil, regolith, vegetation and rocks.
- In Debris slide there is no backward movement.
Slump-
- Slump is slipping of one or several units of rock debris with a backward rotation with respect to the slope over which the movement takes place.
Debris flow and mud flow-
- The rapid downslope movement of debris flow carrying clasts ranging in size from clay particles to boulders and often a large amount of woody debris.
- Mudflow is a debris flow which is principally composed of mud and is saturated with water.
- The above discussed movements are called Rapid movements but there are also some Slow movements in Mass Wasting.
Slow Movements-
Creep-
- It is the slow tilting of the large mass of the land.
- It is most noticeable on moderate-to-steep slopes where trees, fence posts, or grave markers are consistently leaning in a downhill direction.
Solifluction-
- It involves slow downslope flowing soil mass or fine grained rock debris saturated or lubricated with water.
- It is a type of creep.
Erosion-
- It is the geological process in which earthen materials are worn away and transported by natural forces such as wind,water etc.
Agents of erosion-
- These are the agents that causes the erosion and it includes Air,Water,Glacier and ground water etc.
- Kinetic energy is the main force behind occurrence of erosion.
- When either velocity decrease or mass of eroding agents increase than there is depositon of Eroded material.
- Action by waves and ground water is not controlled by climate.
Important One Liner on Mass Wasting
Question 1: What is mass wasting?
Answer: Mass wasting is the downslope movement of soil and rock under the influence of gravity.
Question 2: What are the different types of mass wasting?
Answer: The different types of mass wasting include rockfalls, landslides, debris flows, and creep.
Question 3: What causes mass wasting?
Answer: Mass wasting can be caused by factors such as steep slope angles, weathering and erosion, earthquakes, and human activities.
Question 4: What is a rockfall?
Answer: A rockfall is a type of mass wasting that involves the rapid descent of individual rocks or small rock fragments down a slope.
Question 5: What is a landslide?
Answer: A landslide is a type of mass wasting that involves the movement of a mass of soil, rock, or debris down a slope.
Question 6: What is a debris flow?
Answer: A debris flow is a type of mass wasting that involves a mixture of soil, rock, and water flowing downhill like a fluid.
Question 7: What is creep?
Answer: Creep is a slow, gradual movement of soil and rock downhill due to gravity.
Question 8: How can human activities contribute to mass wasting?
Answer: Human activities such as deforestation, construction, and mining can destabilize slopes and contribute to mass wasting.
Question 9: What are some ways to prevent mass wasting?
Answer: Some ways to prevent mass wasting include stabilizing slopes with retaining walls or vegetation, reducing water infiltration, and avoiding construction on unstable slopes.
Question 10: What are the potential hazards of mass wasting?
Answer: Mass wasting can cause property damage, loss of life, and environmental damage such as the blocking of rivers and streams.