Mass movement Flashcards
What is mass movement?
The downhill movement of material under the influence of gravity.
What is a key fact about mass movement? What does this depend upon?
It can range in speed from extremely slow (1cm per year) to extremely fast dependent upon the weight of the rainwater and the weakness of the geology.
What is soil creep/ solifluction?
Individual soil particles move continuously downhill under gravity so the hillside looks stepped.
What is the rate of movement if soil creep/solifluction?
Slow
Is soil creep/solifluction a wet or dry process?
Wet or dry
What is mudflow?
The soil become densely saturated (unable to percolate deep into ground) so surface layers of fine material become fluid and flow downhill.
What is the rate of movement of mudflow?
Fast
Is mudflow a wet or dry process?
Wet
What is rock fall?
Cliffs are undercut by the sea in the intertidal zone so upper rocks become too heavy and collapse. This process is also caused by freeze thaw.
What is the rate of movement of rock fall?
Fast
Is rock fall a wet or dry process?
Wet or dry
What is slumping/rotational slip?
On cliffs where softer material lies on top of more resistant materials, sections of the cliff move downwards with a slide plane that is concave, producing a rotational movement.
What is the rate of movement of slumping/rotational slip?
Slow
Is slumping a wet or dry process?
Wet
What are landslides?
Cliffs made from softer rocks or deposited material slip when lubricated following heavy rainfall.