Q. Compare and contrast the causes of landslides in the Himalayan region and the Western Ghats. What role does human activity play in exacerbating this natural phenomenon? (10 marks and 150 words)
Approach:
- Introduction: Define landslides and mention their significance in both regions
- Body:
- Causes of landslides in the Himalayan region
- Causes of landslides in the Western Ghats
- Similarities and differences between the two regions
- Human activities exacerbating landslides in both areas
- Conclusion: Summarize key points and suggest measures to mitigate landslide risks
Model Answer:
Introduction: Landslides, the downslope movement of rock, debris, or earth, pose significant threats to life and property in the Himalayan region and Western Ghats. These geologically distinct areas experience frequent landslides due to various natural and anthropogenic factors.
Body:
|
Aspect |
Himalayan Region |
Western Ghats |
|
Geological Factors |
Young and fragile mountain system with ongoing tectonic activity Presence of numerous fault lines and seismic zone Steep slopes and unstable rock formations |
Lateritic soil composition prone to erosion Presence of faults and joints in rock formations |
|
Climatic Factors |
Heavy monsoon rainfall leading to soil saturation Snowmelt in higher altitudes causing water accumulation |
Heavy and intense rainfall during monsoons High humidity leading to increased weathering |
|
Hydrological/Topographical Factors |
Glacial lake outburst floods (GLOFs) River erosion at the base of slopes |
Steep slopes and escarpments Presence of numerous streams and rivers causing erosion |
|
Similarities |
Heavy monsoon rainfall Steep slopes Geological instability |
Heavy monsoon rainfall Steep slopes Geological instability |
|
Differences |
Tectonically active Glacial activity present Diverse rock types |
Relatively stable tectonically No glacial activity More lateritic soil |
Human activities exacerbating landslides:
- Deforestation reduces soil cohesion and increases erosion, as seen in the 2013 Uttarakhand floods. Loss of vegetation destabilises slopes and alters local hydrology.
- Infrastructure development, especially improper road construction, can trigger landslides. The Mumbai-Pune Expressway exemplifies how inadequate slope stabilisation leads to frequent landslides.
- Mining activities destabilise slopes and alter drainage patterns. Illegal mining in Goa has increased landslide incidents by fundamentally changing the landscape.
- Rapid urbanisation in hilly areas, like in Shimla, increases surface runoff and alters natural drainage, leading to more frequent landslides.
- Certain agricultural practices, such as terrace farming without proper drainage, can cause soil instability. The Nilgiris region has seen increased risks due to shifts in farming methods.
- Improper water management, including dam construction and inadequate drainage systems, affects slope stability. The Tehri Dam in Uttarakhand demonstrates how large projects can impact local hydrology and landslide risk.
Conclusion: While natural factors primarily cause landslides in the Himalayas and Western Ghats, human activities significantly exacerbate the risks. Implementing sustainable land-use practices, improving early warning systems, and enhancing community preparedness are crucial for mitigating landslide hazards in these vulnerable regions.
