UPSC MainsGENERAL-STUDIES-PAPER-I202110 Marks150 Words
Q4.

Differentiate the causes of landslides in the Himalayan region and Western Ghats. (Answer in 150 words)

How to Approach

This question requires a comparative analysis of landslide causes in two distinct geographical regions – the Himalayas and the Western Ghats. The answer should focus on the geological, topographical, climatic, and anthropogenic factors specific to each region. A structured approach comparing these factors will be most effective. Briefly outlining the geological setup of each region is crucial. The answer should be concise, sticking to the 150-word limit, and demonstrate an understanding of geomorphological processes.

Model Answer

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Introduction

Landslides are a frequent and devastating natural hazard in India, particularly in the geologically fragile Himalayan and Western Ghats regions. While both regions experience landslides, their underlying causes differ significantly due to variations in their formation, lithology, and climatic conditions. The Himalayas, born of tectonic collision, are younger and more prone to seismic activity, while the Western Ghats are a result of Deccan volcanic activity and subsequent erosion. Understanding these differences is crucial for effective disaster management and mitigation.

Causes of Landslides: A Comparative Analysis

The Himalayan region experiences landslides primarily due to:

  • Tectonic Activity: Frequent earthquakes and seismic instability weaken slopes.
  • Young Geology: Unconsolidated sedimentary rocks and fragile formations.
  • Heavy Rainfall: Intense monsoon precipitation saturates slopes, increasing pore water pressure.
  • Glacial Retreat: Creates unstable slopes and increases debris flow.
  • Deforestation: Reduces vegetation cover, diminishing slope stability.

In contrast, the Western Ghats landslides are largely triggered by:

  • Monsoon Rainfall: Extremely high rainfall, often exceeding 2000mm annually, is the dominant factor.
  • Steep Slopes: The region is characterized by steep, dissected slopes.
  • Lateritic Soil: Weathered, iron-rich lateritic soils are prone to saturation and failure.
  • Basaltic Rock: Jointed basaltic rocks are susceptible to weathering and erosion.
  • Human Activities: Tea, coffee, and spice plantations, along with road construction, contribute to slope destabilization.
Feature Himalayas Western Ghats
Dominant Cause Tectonic Activity & Rainfall Intense Rainfall
Geology Young, Sedimentary & Metamorphic Old, Basaltic
Soil Type Varied, often unconsolidated Lateritic
Anthropogenic Impact Deforestation, Infrastructure Plantations, Road Construction

While rainfall is a common factor, the intensity and geological context dictate the nature and frequency of landslides in each region.

Conclusion

In conclusion, landslides in the Himalayas are more closely linked to tectonic forces and the region’s young geological age, while those in the Western Ghats are primarily driven by intense monsoon rainfall acting on weathered basaltic terrain. Effective landslide mitigation strategies must therefore be tailored to the specific geological and climatic conditions of each region, incorporating robust slope stabilization techniques and sustainable land-use practices.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Landslide
The movement of a mass of rock, earth, or debris down a slope, typically triggered by rainfall, earthquakes, or human activity.
Lateritic Soil
A soil type rich in iron and aluminum oxides, formed in hot and wet tropical areas. It is typically reddish in color and prone to erosion.

Key Statistics

According to the National Disaster Management Authority (NDMA), approximately 15% of India’s land area is prone to landslides. (Data as of 2023)

Source: NDMA

The Western Ghats receive an average annual rainfall of 2000-4000 mm, making it one of the wettest regions in India. (Based on IMD data up to 2022)

Source: India Meteorological Department (IMD)

Examples

Uttarakhand Landslide 2021

The Chamoli district of Uttarakhand experienced a massive landslide in February 2021, triggered by a glacial lake outburst flood, resulting in significant infrastructure damage and loss of life. This exemplifies the impact of glacial retreat and heavy rainfall in the Himalayas.

Frequently Asked Questions

Are landslides predictable?

While predicting the exact timing of a landslide is difficult, landslide susceptibility mapping, rainfall monitoring, and slope stability analysis can help identify areas at high risk and enable early warning systems.

Topics Covered

GeographyEnvironmentGeomorphologyNatural DisastersIndian Geography