Landslides occur when the stability of the 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. Various causes of landslides are given below.
Causes of Landslides:
Natural causes of landslides include:
- Groundwater (pore water) pressure acting to destabilize the slope
- Loss or absence of vertical vegetative structure, soil nutrients, and soil structure (e.g., after a wildfire, fire in forests, etc., lasting for 3–4 days)
- Erosion of the toe of a slope by rivers or ocean waves
- Weakening of a slope through saturation by snow melt, glaciers melting, or heavy rains
- Earthquakes are adding loads to a barely stable slope
- Earthquake-caused liquefaction destabilizes slopes
- Volcanic eruptions
Human activities aggravate landslides:
- Deforestation, cultivation, and construction destabilize the already fragile slopes.
- Vibrations from machinery or traffic
- Blasting
- Earthwork that alters the shape of a slope, or that 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 (logging) that change the amount of water that infiltrates the soil.
Geological causes:
- Weathered Materials, e.g., heavy rainfall
- Sheared materials
- Jointed or fissured materials
- Adversely oriented discontinuities
- Permeability contrasts
- Material contrasts
- Rainfall and snowfall
- Earthquakes
- Working of machinery
Morphological causes:
- Slope angle
- Uplift
- Rebound
- Fluvial erosion
- Wave erosion
- Glacial erosion
- Erosion of lateral margins
- Subterranean erosion
- Slope loading
- Vegetation change
- Erosion
Physical causes:
- Intense rainfall
- Rapid snow melt
- Prolonged precipitation
- Rapid drawdown
- Volcanic eruption
- Thawing
- Freeze-thaw
- Groundwater changes
- Soil pore water pressure
- Surface runoff
- Seismic activity
- Soil erosion
Human causes:
- Excavation
- Loading
- Draw-down
- Land use change
- Water management
- Mining
- Quarrying
- Vibration
- Water leakage
- Deforestation
- Land use pattern
- Pollution
Conclusion:
Landslides severely damage soil, buildings, and human life. This causes a major threat to both humans and nature. To prevent landslides, we should protect trees and plants that keep the soil strong, manage water carefully to prevent soil erosion, avoid building houses on weak hillsides, and plan land use wisely. Following these simple steps can help reduce landslides and keep everyone safe.
