Describe the various causes and effects of landslides. Mention the important components of the National Landslide Risk Management Strategy.

Introduction

Landslides are the downward movement of rock, soil, and debris under the influence of gravity. They are a common natural hazard in India, particularly in the Himalayan region, the Western Ghats, and areas with high rainfall or seismic activity. According to the Geological Survey of India (GSI), 68% of India’s landmass is prone to landslides, making it a critical issue for disaster management.

Key Dimensions of Landslides at a Glance

Causes of Landslides

1. Natural Causes

• Geological factors: Weak or fractured rock formations, steep slopes, and loose soil increase susceptibility.
• Climatic factors: Intense or prolonged rainfall leads to soil saturation, reducing cohesion and triggering landslides.
  • Example: The 2013 Kedarnath disaster was exacerbated by heavy rainfall.
• Seismic activity: Earthquakes destabilize slopes, especially in tectonically active regions like the Himalayas.
  • Example: The 2015 Nepal earthquake caused widespread landslides in adjoining Indian regions.
• Volcanic activity: Lava flows and ash deposits can destabilize slopes.
  • Example: Landslides during the 1991 eruption of Mount Pinatubo in the Philippines.

2. Anthropogenic Causes

• Deforestation: Removal of vegetation reduces slope stability by weakening root binding.
  • Example: Deforestation in the Western Ghats has increased landslide frequency.
• Unplanned construction: Infrastructure development, such as roads and dams, alters natural drainage patterns and destabilizes slopes.
• Mining and quarrying: Excavation activities weaken the structural integrity of slopes.
• Agricultural practices: Shifting cultivation and terracing can lead to soil erosion and slope instability.

Effects of Landslides

1. Environmental Impact

• Loss of biodiversity: Landslides destroy habitats and ecosystems.
  • Example: The 2020 landslides in Uttarakhand led to significant forest loss.
• Soil erosion: Topsoil is washed away, reducing land fertility.
• River blockages: Landslides can dam rivers, leading to flooding or creating unstable reservoirs.

2. Economic Loss

• Damage to infrastructure: Roads, bridges, and buildings are often destroyed.
  • Example: The 2021 landslides in Himachal Pradesh caused damage worth ₹1,000 crore.
• Disruption of livelihoods: Agriculture, tourism, and trade are severely affected in landslide-prone areas.

3. Human Casualties

• Loss of life: Landslides often result in fatalities, especially in densely populated areas.
  • Example: The Malin landslide in Maharashtra (2014) claimed over 150 lives.
• Displacement: Affected communities are forced to relocate, leading to social and psychological stress.

National Landslide Risk Management Strategy: Key Components

The National Landslide Risk Management Strategy (prepared by the NDMA) aims to reduce landslide risks through a multi-pronged approach. Its key components include:

1. Hazard Mapping and Zonation

• Identification of landslide-prone areas using GIS and remote sensing.
• Preparation of detailed landslide susceptibility maps.

2. Monitoring and Early Warning Systems

• Installation of real-time monitoring systems in high-risk zones.
• Development of early warning systems to alert communities.

3. Capacity Building and Awareness

• Training programs for local communities, engineers, and planners.
• Public awareness campaigns to educate people about landslide risks and mitigation measures.

4. Structural and Non-Structural Measures

• Construction of retaining walls, slope stabilization, and bioengineering solutions.
• Regulation of land use and enforcement of building codes in vulnerable areas.

5. Disaster Response and Recovery

• Development of contingency plans for landslide-prone regions.
• Provision of financial assistance and rehabilitation for affected communities.

6. Research and Development

• Encouraging studies on landslide dynamics, risk assessment, and mitigation technologies.
• Collaboration with academic institutions and international organizations.

Way Forward

To mitigate landslide risks, India must adopt a proactive approach by integrating scientific research, community participation, and robust policy implementation. Strengthening the National Landslide Risk Management Strategy with adequate funding, inter-agency coordination, and international best practices will be crucial in reducing the socio-economic and environmental impacts of landslides.

Conclusion

Landslides are a significant challenge for India, given its diverse topography and climatic conditions. By implementing the National Landslide Risk Management Strategy effectively and fostering community resilience, India can minimize the devastating effects of landslides and ensure sustainable development in vulnerable regions.