UPSCpedia: Geograpedia - Landslides

• A landslide is a geological phenomenon which includes a wide range of ground movement, such as rockfalls, deep failure of slopes and shallow debris flows, which can occur in offshore, coastal and onshore environments.
• Although the action of gravity is the primary driving force for a landslide to occur, there are other contributing factors affecting the original slope stability.
• Natural causes of landslides include:
  • Groundwater (porewater) pressure acting to destabilize the slope
  • Loss or absence of vertical vegetative structure, soil nutrients, and soil structure (e.g. after a wildfire)
  • 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
  • Earthquake-caused liquefaction destabilizing slopes
  • Volcanic eruptions
• Landslides are aggravated by human activities, Human causes include:
  • Deforestation, cultivation and construction, which destabilize the already fragile slopes
  • Vibrations from machinery or traffic (bridges, road, railway track construction)
  • Earthwork which alters the shape of a slope, or which imposes new loads on an existing slope
  • Construction, agricultural or forestry activities (logging) which change the amount of water which infiltrates the soil.