Theory question 205
Weathering, Erosion and Mass Movement(a) Define the term mass wasting. (b) Describe two types of mass wasting. (c) State three effects of mass wasting.
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(a) Mass wasting (mass movement) is the movement of weathered rock and soil down a slope under the force of gravity.
(b) Soil creep: very slow, hardly noticeable movement of soil down gentle slopes, caused by wetting and drying, freezing and thawing, rain splash; shown by tilted posts, trees and walls. Landslide: sudden rapid movement of large masses of rock and soil down steep slopes, often after heavy rain or earthquakes, when the material is lubricated. Others: mudflow, earthflow, slump, solifluction, rockfall.
(c) Loss of farmland and soil fertility; destruction of buildings and displacement of settlements; blocking of roads and railways and damage to power lines; damming of rivers and flooding; loss of life.
Define first, then give each type its speed, cause and evidence.