coasts L9 mass movement processes & landforms

Question 1

What is MASS MOVEMENT (downslope of rocks, sans clay or till/soil) caused by?

Answer 1

• GRAVITY once a slope has become unstable
• rainwater enters unconsolidated material creating PORE PRESSURE
• water content determines the type of mass movement
• slope angle and vegetation cover also determines stability
• can be triggered by tectonic activity

Question 2

what is SOIL CREEP?

Answer 2

SLOW movement of OVERSATURATED soil on a LOW GRADIENT SLOPE

Holderness

Question 3

what is a ROCK FALL

lol

Answer 3

blocks of rock DISLODGED by MECHANICAL WEATHERING or HYDRAULIC ACTION
UNDERCUTTING of cliffs by creation of WAVE CUT NOTCHES can lead to large falls

Cornish Coastline (newquay)

Question 4

what is a MUD/EARTHFLOW

Answer 4

clay/unconsolidated materials become saturated, LOSE COHESION and FLOW DOWNSLOPE
triggered by heavy rainfall and high tides

Solway Coast

Question 5

what is a ROTATIONAL SLUMP

Answer 5

curved failure surface
huge masses of material slowly ROTATE DOWNSLOPE over periods lasting days to years
creates TERRACING

Holderness - Skipsea

Question 6

what is a LANDSLIDE

Answer 6

base of SLOPED cliff erodes causing the above to slide down

Cliffs of Dover