Main causes of mass movements :
- Removal of support from below to materials above through natural or artificial means.
- Increase in gradient and height of slopes.
- Overloading through addition of materials naturally or by artificial filling.
- Overloading due to heavy rainfall, saturation and lubrication of slope materials.
- Removal of material or load from over the original slope surfaces.
- Occurrence of earthquakes, explosions or machinery.
- Excessive natural seepage.
- Heavy drawdown of water from lakes, reservoirs and rivers leading to slow outflow of water from under the slopes or river banks.
- Indiscriminate removal of natural vegetation