Studied by 12 people
what are landslides and rockfalls
a weakness point in a slope causes material above it to crash down at high speeds. land can be destabilised by heavy rainfall or earthquakes and can trigger tsunamis or block waterways to create lakes
what are mudflows
clay rich soil that is not bound by plant matter becomes saturated and flows. they behave like a liquid so often follow river valleys. lahars are a type of mudflow
what is soil creep
shear stress is not strong enough to cause a landslide or rockfall so land slowly inches forward over years or centuries
what are the three types of soil creep (3)
continuous, seasonal according to soil moisture, progressive in the build up to another mass movement
what is a slump
when a layer of a slope slips downwards. they form in sediment rich soils that behave as a coherent body
what is the role of gravity in mass movements
it is the initial force that pulls earth down or props it up
what is the role of pore pressure in mass movements
it destabilises slopes when it increases such as in saturated soil
what is the role of slope angle in mass movements
steeper slopes are more likely to trigger landslides
what is shear strength
how much the earth resists being moved
what is shear stress
the combination of forces encouraging earth to move
what are the two ways mass movements can be classified (2)
moisture, speed
Note 
Flashcard (46)