Q.Differentiate the causes of landslides in the Himalayan region and Western Ghats.

Introduction

A landslide refers to the downward movement of a mass of rock, soil, or debris along a slope. It is a form of mass wasting driven primarily by gravity, influenced by geological, morphological, and human-induced factors.

Body

Causes in the Western Ghats:

• Mining and Quarrying: Intensive mining activities in the Western Ghats region act as a major factor destabilizing slope structures.

• Deforestation: Extensive clearing of forests for human settlements and road construction weakens soil cohesion.

• Anthropogenic Slopes: Human activities create unnatural, steep slopes that succumb to gravity and heavy rainfall.

• Concentrated Rainfall: High susceptibility to landslides during intense, localized monsoon downpours.

• Infrastructure Projects: Large-scale projects, such as wind farms, cause structural fracturing in mountainous terrains (e.g., in regions like Ratnagiri, Satara, and Idukki).

Causes in the Himalayas:

• Tectonic Instability: Unlike the stable Western Ghats, the Himalayas are young fold mountains that are seismically active and fragile.

• Steep Slopes and High Relief: High vertical gradients make slopes naturally unstable and prone to gravity-driven mass wasting.

• Heavy Rainfall and Cloudbursts: Intense precipitation triggers rapid soil saturation, leading to sudden debris flows and mudslides.

• Unplanned Urbanization: Rapid construction, road widening, and hydel projects destabilize the fragile slopes.

Measures for Landslide Mitigation:

• Imposing strict regulations on construction, road building, and dam development in high-risk zones.

• Restricting agricultural activities to flatter valleys and moderate slopes.

• Implementing extensive afforestation programs and constructing retaining walls/bunds to control water runoff.

Conclusion

Landslide hazards have escalated due to human interventions. Implementing the recommendations of the Madhav Gadgil and Kasturirangan committees, along with NDMA guidelines, is crucial for sustainable mountain development.