Subject: Indian Geography

India's diverse physiography presents unique landslide scenarios in its two prominent mountain ranges - the Himalayas and the Western Ghats, each having distinct causative factors for mass movements.

Causes of Landslides in Himalayan Region

• Geological Factors:

• Complex lithology comprising mudstones, sandstones, shales, and metamorphic rocks makes the region inherently unstable.
• Active tectonic movements and frequent seismic activities (e.g., 7.1 magnitude earthquake in Nepal-China border in 2025) trigger mass movements.
• The splitting of Indian tectonic plate beneath Tibet further increases landslide vulnerability.

• Climatic Factors:

• Heavy monsoon precipitation and cloud bursts lead to soil saturation.
• Rapid snow melting in higher altitudes causes soil instability.
• Extreme temperature variations result in rock weathering.

• Anthropogenic Causes:

• Unplanned infrastructure development and road cutting.
• Deforestation and changes in traditional land-use patterns.
• Hydroelectric projects causing slope destabilization.

Causes of Landslides in Western Ghats

• Geological Factors:

• Presence of horizontal lava sheets and granitoid gneiss formations.
• Relatively stable geological structure compared to Himalayas.
• Weathered rock formations due to tropical climate.

• Climatic Factors:

• Intense rainfall (over 6000mm annually in some regions) during monsoons.
• High humidity leading to chemical weathering of rocks.
• Soil saturation due to concentrated precipitation.

• Anthropogenic Causes:

• 11% decline in natural forest cover (1991-2023) affecting slope stability.
• Mining activities and quarrying operations.
• Agricultural practices on steep slopes.

Comparative Analysis

• Intensity and Frequency:

• Himalayan landslides are more catastrophic due to higher relief and seismic activity.
• Western Ghats experiences more seasonal and rainfall-induced slides.

• Risk Factors:

• Himalayas: Tectonic activity, complex geology, and development pressure.
• Western Ghats: Monsoon intensity and land-use changes.

The contrasting causes of landslides in these regions necessitate region-specific mitigation strategies. While the Himalayas require focus on seismic-resistant infrastructure and geological monitoring, the Western Ghats need emphasis on watershed management and forest conservation measures like the Green India Mission for effective disaster risk reduction.