Differentiate the causes of landslides in the Himalayan region and Western Ghats.
GS110 Marks2021Model answer
Introduction
Landslides are a common geomorphological hazard in India, particularly in the Himalayan region and the Western Ghats, both of which are prone to slope instability due to their unique geological, climatic, and anthropogenic factors. While both regions experience landslides, the causes differ significantly due to variations in their topography, geology, and human activities.
Key Differences at a Glance
| Aspect | Himalayan Region | Western Ghats |
|---|---|---|
| Geology | Young, tectonically active fold mountains | Stable, ancient block mountains |
| Climatic Influence | Intense monsoons and snowmelt | Heavy monsoons |
| Anthropogenic Factors | Road construction, deforestation, unplanned urbanization | Quarrying, deforestation, plantation agriculture |
Causes of Landslides in the Himalayan Region
1. Geological Factors
- Young and tectonically active mountains: The Himalayas are geologically young and still rising due to the collision of the Indian and Eurasian plates, making them inherently unstable.
- Seismic activity: Frequent earthquakes weaken slopes, triggering landslides (e.g., 2015 Nepal earthquake-induced landslides).
- Weak lithology: Presence of soft sedimentary rocks and unconsolidated debris increases susceptibility.
2. Climatic Factors
- Snowmelt and glacial retreat: Melting glaciers and snow during summer destabilize slopes.
- Intense rainfall: Heavy monsoons, especially cloudbursts, saturate soil and cause slope failure (e.g., Kedarnath floods, 2013).
3. Anthropogenic Factors
- Unplanned infrastructure development: Road construction and hydropower projects disturb slope stability.
- Deforestation: Large-scale deforestation for agriculture and settlements reduces slope cohesion.
- Tourism pressure: Increased footfall in ecologically sensitive zones exacerbates instability.
Causes of Landslides in the Western Ghats
1. Geological Factors
- Ancient and stable mountains: The Western Ghats are older and geologically stable but have steep escarpments prone to landslides.
- Lateritic soil: The presence of lateritic soil, which becomes loose and unstable when saturated, contributes to landslides.
2. Climatic Factors
- Heavy monsoons: The Western Ghats receive some of the highest rainfall in India, leading to waterlogging and slope failure (e.g., Kerala floods, 2018).
- Cyclonic activity: Occasional cyclones intensify rainfall, triggering landslides.
3. Anthropogenic Factors
- Quarrying and mining: Extensive quarrying for construction materials destabilizes slopes.
- Deforestation and plantation agriculture: Conversion of forests into plantations (e.g., tea, coffee) reduces root binding of soil.
- Unregulated construction: Urbanization in hill towns like Munnar increases vulnerability.
Way Forward
- Himalayan Region: Implement eco-sensitive zoning, regulate hydropower projects, and promote afforestation to stabilize slopes.
- Western Ghats: Enforce the recommendations of the Madhav Gadgil Committee and Kasturirangan Committee to ensure sustainable development.
- Common Measures: Use bioengineering techniques, early warning systems, and community-based disaster management to mitigate landslide risks.
Conclusion
While both the Himalayan region and the Western Ghats face landslide risks, the underlying causes are shaped by their distinct geological and climatic contexts. A region-specific, sustainable approach is essential to mitigate the impact of landslides and protect lives and livelihoods.
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