coastal systems -geomorphological processes (sub aerial -mass movement)

Question 1

what is mass movement?

Answer 1

.the downhill movement of material due to the influence of gravity

Question 2

what are mass movements important in?

Answer 2

.transferring both energy and sediment

Question 3

what are the 4 types of mass movement?

Answer 3

.soil creep
.rockfall
.landslide
.mudflow
.rotational slumping
.runoff
.solifluction

Question 4

what is soil creep?

Answer 4

.where soil particles on a hill slope get wet after rainfall
.they are now heavier and there is less friction as the rainfall lubricates the particles so they slowly move/creep downslope
.when the soil dries out, it stops moving -slowest form of mass movement

Question 5

what is rockfall?

Answer 5

.rocks -often resistant rocks are on a steep and vertical cliff face
.mechanical weathering such as freeze thaw occurs repeatedly over time so large blocks of rock break away/fall from the cliff face
.scree forms at the base of the cliff until material is removed by waves

Question 6

what is a landslide?

Answer 6

.rock that is on a planar surface (the hill has a flat edge)
.rainfall occurs and lubricates the land surface, reducing friction
.solid blocks of material move/slide down the hill rapidly -can be triggered by earthquakes

Question 7

what is mudflow?

Answer 7

.where earth and mud are on a hillslope
.rainfall fills pores (spaces) in the soil and this increases pressure
.the mud particles are also heavier due to being wet
.the sediment moves/flows downhill and mixes together in a rapid and dangerous mudflow

Question 8

what is rotational slumping?

Answer 8

.material that is on a curved surface -often permeable rock overlies impermeable rock
.rainfall occurs and can percolate through the permeable rock but not the impermeable so a layer of water forms, causing pressure Sony he saturated layer of material moves/slumps downhill

Question 9

what is runoff?

Answer 9

.surface runoff/overland flow occur following a rainfall event
.small particles flow downslope within the overland flow to the littoral zone (input into sediment cell)

Question 10

what is solifluction?

Answer 10

.the same as soil creep except it is in cold environments
.frozen soil thaws in summer and becomes saturated
.the saturated soil moves/creeps downhill over a layer of permafrost