What is a landslide??
A landslide is a geological phenomenon which includes a wide range of ground movement, such as rock falls, deep failure of slopes and shallow debris flows. Although the action of gravity on an over-steepened slope is the primary reason for a landslide, there are other contributing factors affecting the original slope stability.
Causes of landslides.
The Mameyes Landslide, which buried more than 100 homes, was caused by extensive accumulation of rains and, according to some sources, lightning.Landslides are caused when the stability of a slope changes from a stable to an unstable condition. A change in the stability of a slope can be caused by a number of factors, acting together or alone:
Natural causes:
- Erosion of the toe of a slope by rivers or ocean waves
- Weakening of a slope through saturation by snowmelt, glaciers melting, or heavy rains
- Earthquakes adding loads to barely-stable slopes
- Earthquake-caused liquefaction destabilizing slopes
- Volcanic eruptions
- Groundwater pressure acting to destabilize the slope
Human Causes:
- Vibrations from machinery or traffic
- Blasting
- Earthwork which alters the shape of a slope, or which imposes new loads on an existing slope
- In shallow soils, the removal of deep-rooted vegetation that binds colluvium to bedrock
- Construction,agricultural, or forestry activities which change the amount of water which infiltrates into the soil
