Mass Movement Flashcards
Name the 6 types of mass movement.
Landslides. Rock falls. Mudflows. Slides/slumping. Soil creep. Run-off.
What are landslides?
Occur on cliffs made from softer rocks or deposited material, which slip as a result of ‘failure’ within in when lubricated.
Usually following heavy rainfall.
What are rockfalls?
Occur from cliffs undercut by the sea or on slopes affected by mechanical weathering like frost action.
What are mudflows?
Heavy rain causes large quantities of fine material to flow downhill.
The soil becomes saturated and if excess water can’t percolate deeper into the ground surface layers become very fluid and flow downhill.
What are mudflows dependent on?
On the level of saturation, type of sediment and slope angle.
What are slides/slumping?
Where softer material overlies much more resident materials.
With excessive lubrications whole sections of cliff may move downwards with a side plane that is concave producing a rotation movement.
Give an example of where slumps are?
East Yorkshire.
North Norfolk.
What is soilcreep?
It occurs when there is a very slow almost imperceptible but continuous movement of individual soil particles downslope.
How do geographers think soilcreep occurs?
The presence of soil moisture with weathering and other processes.
What is run-off?
Large quantity of load that happens during times of flood.
Water that flows over the surface to reach the coastline.
What is solifluction?
Happens in cold environments.
In summer the surface layer thaws out and becomes extremely saturated.
It lies on top of the frozen ground.
Active top layer moves downslope.
Name 4 factors mass movement is dependent upon ?
Level of cohesion within sediment.
Height of slopes and angle.
Grain size of sediment.
Temp / saturation
Define mass movement
Generally rapid suddenly failures of slope or effects or processes that develop over some time.
