Mass Movements Flashcards
What is mass movement?
Mass movement occurs when the forces acting on slope material (mainly the resultant force of gravity) exceed the forces trying to keep the material on the slope (predominantly friction).
What are the most significant mass movement processes in coastal landscape systems?
The most significant mass movement processes in coastal landscape systems are those acting on steep slopes, which lead to the addition of material to the glacier below, loading it with debris and providing the tools for abrasion.
What is rock fall?
Rock fall is a process in which on slopes of 40° or more, especially if the surface is bare, rocks may become detached from the slope by physical weathering processes. These then fall to the foot of the slope under gravity.
What happens to the material after rock fall?
Transport processes may then remove this material, or it may accumulate as a relatively straight, lower angled scree slope.
What are slides?
Slides are mass movements that may be linear, with movement along a straight line slip plane, such as a fault or a bedding plane between layers of rock, or rotational, with movement taking place along a curved slip plane.
What are rotational slides known as?
Rotational slides are also known as slumps.
What causes slides in glaciated landscape systems?
In glaciated landscape systems, slides may occur due to steepening or undercutting of valley sides by erosion at the base of the slope, adding to the downslope forces.
What kind of rocks are common in slumps?
Slumps are common in weak rocks, such as clay, which also become heavier when wet, adding to the downslope force.
