Types of Mass Movement
Mass movement is also known as mass wasting. It’s a geomorphic process whereby sand, soil, rock and regolith moves down the slope as a mass. These types of movements are differentiated based on the rock, soil and regolith movement down-slope as a whole. It can also be differentiated by the speed of the movement (de Vallejo & Ferrer, 2011).
Soil creep is considered a long process. During this type of mass movement the rock or soil over time and in different direction are directed by gravity down-slope. The steeper the slope the greater and faster the creep. In order to maintain their perpendicularity the creeps gets attached to trees and shrubs meaning that creeps are affected by vegetation cover. The difference between landslides and creeps is that creeps can lead to landslide but the reverse is not true. The other difference is that creeps can be caused by physical process such as human beings but a landslide is only caused by water.
Landslides is also called landslip. This is the movement of a large mass of rock or earth down a mountain or hill. Flowage of material occurs in a given slope until a resultant lubrication of rain aid in the movement of the materials leading to the occurrence of landslide (Debella-Gilo & Kääb, 2011). The types of landslides are debris fall, avalanche, and rock fall and debris slide. The difference between landslide and creep is that landslide is a movement of heavy and large materials but creep is movement of small materials such as rock or soil. Landslip is more dangerous than creep due to its mass.
This is a slip of rock along a curved surface of a slope. It is a movement of rock or soil along a curved surface. It forms a crescent shaped scrap at the top of the slope. Since slump takes place in a curved surface it is less dangerous as compared to other mass movements.
This is the movement of a regolith down a slope with less force to act as a flow. Falls are characterized with rock fall by the presence of vertical cracks. Falls are resultant of water and waves undercutting. It takes place at steep slopes. The rock material may be loosened by rain earthquakes etc. the difference between falls and slump is that slump takes place in a curved surface while falls takes place in a steep slope (Hoffer, 2011).
Triggers of Mass Movement
Overburden from heavy structures
Increase in the soil moisture
Reduction of soil holding materials such as roots and trees
de Vallejo, L. I. G., & Ferrer, M. (2011). Geological engineering. CRC Press.
Debella-Gilo, M., & Kääb, A. (2011). Sub-pixel precision image matching for measuring surface displacements on mass movements using normalized cross-correlation. Remote Sensing of Environment, 115(1), 130-142.
Hoffer, E. (2011). The true believer: Thoughts on the nature of mass movements. HarperCollins.