The high frequency of landslides in many parts of India due to recent heavy rains is drawing attention across the globe. This article closely examines landslides, their causative factors and potential mitigation techniques, with a special focus on India, one of the most landslide-prone zones.
Understanding Landslides
A landslide involves the downward movement of a mass of rock, debris, or earth down a slope. This act is a form of mass wasting, a term describing any downward movement of soil and rock under direct gravitational force. The umbrella term ‘landslide’ covers five types of slope movements: falls, topples, slides, spreads, and flows.
Causes Behind Landslides
Landslides occur when the downward forces, primarily gravity, surpass the strength of the earth materials constituting the slope. Three main factors can incite a landslide: geology, morphology, and human activity.
Geology relates to the specific characteristics of the materials involved. For instance, the earth or rock may be weak or fractured, or different layers could possess disparate strengths and stiffness.
Morphology denotes the land’s structure. Slopes that have lost their vegetation due to fire or drought are more susceptible to landslides as vegetation retains soil in place. Without the root systems of trees, shrubs, and other plants, the land becomes more prone to sliding away.
Lastly, human activities significantly contribute to causing landslides. Agriculture and construction increase the likelihood of a landslide, exploiting the natural resources, thus destabilizing the landscape.
Region-wise Impact of Landslides
From a continental perspective, Asia faces the maximum damages and losses from landslides, with South-Asian nations being the hardest hit. Within this region, India ranks among the nations worst affected by landslides, highlighting the urgent need for effective mitigation strategies.
Landslide Mitigation Measures
There are several potential solutions to reduce the vulnerability to landslides. These include restrictions on construction and other developmental activities such as roadways and dams in landslide-prone areas.
Limits on agriculture — confining it to valleys and regions with moderate slopes — can also help reduce the risk. Further, controlling the growth of large settlements in high vulnerability zones is critical for overall safety.
Promoting large-scale afforestation programmes and constructing bunds to inhibit water flow is another effective measure. In the northeastern hill states of India, where Jhumming (Slash and Burn/Shifting Cultivation) is still common, encouraging terrace farming can significantly reduce the rate of landslides.
While landslides continue to pose significant challenges globally, understanding their causes and implementing effective mitigation measures can significantly reduce their devastating impacts, especially in critically vulnerable areas like India.
Last Modified: February 8, 2024