UPSC CSE 2021 Main GS Paper 1
Question 4 - Differentiate the causes of landslides in the Himalayan region and western ghats.
Answer-
Landslides are the movement of mass of debris, earth, or rock, sliding down under the effect of gravity. Landslides are a common problem across the Himalayan region and Western Ghats. However, the causes for the two differ, as seen in the following table:
Tectonic activity: The Himalayas are young, fragile mountains still growing due to the collision of the Indian and Eurasian plates. This causes instability and seismicity, which can trigger landslides even during dry seasons.
Steep slopes: The Himalayas have steep and sharp slopes, which increase the gravitational pull and the potential energy of the overlying material. This makes them more susceptible to landslides due to any disturbance or weakening of the slope stability.
High rainfall and snowfall: The Himalayas have high rainfall and snowfall, which increase the risk of avalanches and soil erosion. The melting of snow and glaciers can also cause landslides due to increased water flow and slope failure.
Anthropogenic factors: The Himalayas have human activities, such as shifting cultivation, road construction, tourism, and industrial growth, which contribute to landslides. These activities alter the land use pattern, increase the slope load, cut or fill the slopes, change the drainage pattern, and generate vibrations and shocks.
Western Ghats
Heavy rainfall: The Western Ghats experience heavy rainfall during the monsoon season, which can cause landslides due to soil saturation and increased water pressure.
Soil erosion: The Western Ghats have erodible soil types, such as laterite and red soil, which are easily washed away by rainwater or surface runoff. This reduces the cohesion and friction of the soil and makes it more prone to landslides.
Deforestation and mining: The Western Ghats have been subjected to deforestation and mining activities, which disturb the natural balance and stability of the slopes. These activities remove the vegetation cover, which acts as a natural binder and protector of the soil. They also create cracks and fractures in the rocks, which weaken their strength and resistance.
Anomalous slopes: The Western Ghats have some anomalous slopes, which are formed due to geological processes such as faulting, folding, or volcanic activity. These slopes are unstable and prone to landslides due to their irregular shape, orientation, or structure.
Thus, we can see that landslides in the Himalayan region and Western Ghats have different causes, which are related to their respective geological and environmental characteristics. These causes need to be understood and addressed in order to prevent or mitigate the impacts of landslides.