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Chapter 6 - Geog
Mass Movement
Term | Definition |
---|---|
Regolith is | loose rocks and material. |
Mass Movement is | the movement of regolith(loose rocks) down a slope, caused by gravity. The steeper the slope the faster the mass movement. |
4 things that influence are | 1.Slopes –Mass movement is faster on steep slopes. 2.Water Content –Wet regolith is heavier, moves downhill faster. 3.Human Activity– People cut away bottom of hills making slope steeper. 4.Vegetation –The roots of trees etc help slow down massmovement |
There are 4 different types of mass movement. Some of these move slow down a hill and some move fast. | Slow types- Soil Creep Fast types- Landslides, bogbursts, mudflows |
Soil Creep is | 1.the slowest type of mass movement. 2.Anything that loosens the soil, such as freeze-thaw action or burrowing of animals causes soil creep. 3.hard to see and may be seen on surface objects, e.g. leaning walls, fences, trees, electricity poles. |
Landslides are | 1. Very fast movement of earth or rock down a cliff or very steep slope. 2. Occurs when the bottom of the slope is cut away. This happens by sea erosion, road building and quarrying. 3.Landslides are common in mountainous areas or cliffs. |
Bogbursts are | 1. Happen on Irish slopes covered in turf or peat after long periods of rain. 2. The rainwater can’t drain away and the peat becomes heavy. 3. It then flows downhill like runny porridge and can cause great damage |
Mudflows are | 1. Mudflows are similar to bogbursts but move much faster. 2. Happen when wet, heavy regolith flows very quickly down a hill. 3.Small mudflows are common in Ireland but larger ones usually happen with volcanic eruptions. |