Recently, heavy rains caused flash floods and landslides in many parts of Himachal Pradesh.
- A landslide is defined as the movement of a mass of rock, debris, or earth down a slope.
- They are a type of mass wasting, which denotes any downward movement of soil and rock under the direct influence of gravity.
- The term landslide encompasses five modes of slope movement: falls, topples, slides, spreads, and flows.
- Slope movement occurs when forces acting downward (mainly due to gravity) exceed the strength of the earth materials that compose the slope.
- Landslides are caused due to three major factors: geology, morphology, and human activity.
- Geology refers to characteristics of the material. The earth or rock might be weak or fractured, or different layers may have different strengths and stiffness.
- Morphology refers to the structure of the land. For example, slopes that lose their vegetation to fire or drought are more vulnerable to landslides.
- Vegetation holds soil in place, and without the root systems of trees, bushes, and other plants, the land is more likely to slide away.
- Human activity which includes agriculture and construction increases the risk of a landslide.
SOURCE: THE HINDU,THE ECONOMIC TIMES,MINT