Q.Bring out the causes for more frequent landslides in the Himalayas than in Western Ghats.

Introduction

Landslides are gravity-driven downslope movements of soil, rock, and organic debris. While both the Himalayas and the Western Ghats are highly vulnerable to landslide hazards, the Himalayas experience landslides far more frequently and destructively. This disparity is driven by fundamental differences in their geological age, tectonic activity, slope gradients, climatic conditions, and the scale of human intervention.

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Causes for More Frequent Landslides in the Himalayas

• Tectonic Activity and Geological Youth: The Himalayas are geologically young, active fold mountains formed by the ongoing collision of the Indian and Eurasian tectonic plates. This continuous compression makes the region highly unstable, fractured, and seismically active. In contrast, the Western Ghats are older, stable block mountains belonging to the ancient Deccan shield, with highly consolidated, stable rock formations.

• Steep and Rugged Slopes: The Himalayas feature extremely steep, vertical slopes and deep gorges, which maximize the gravitational pull on loose material. The Western Ghats, while steep in some escarpments, generally have gentler, more rounded, and weathered slopes.

• Seismic Triggers: Due to active plate tectonics, the Himalayan region experiences frequent earthquakes and tremors. These seismic shocks loosen rock strata and trigger massive landslides. The Western Ghats lie in a seismically stable zone with minimal earthquake activity.

• Monsoon Intensity and Cloudbursts: The Himalayas, particularly the Eastern Himalayas, experience extreme weather events like cloudbursts and highly concentrated, intense rainfall over short durations. This rapid water influx saturates the soil, increases pore-water pressure, and triggers sudden debris flows. The Western Ghats receive heavy monsoon rainfall, but it is more evenly distributed over time, allowing for better drainage.

• Glacial and Snowmelt Contributions: The melting of glaciers and snow during spring and summer adds a continuous volume of water to unstable slopes in the Himalayas, lubricating rock joints and triggering landslides. This factor is entirely absent in the glacier-free Western Ghats.

• Unconsolidated Soil and Rock Composition: The Himalayan slopes are composed of sedimentary rocks, loose shales, and highly erodible soils that easily give way under heavy rain. The Western Ghats are composed of hard, crystalline basaltic rocks that are highly resistant to erosion.

• Intense Anthropogenic Pressures: The Himalayas have witnessed rapid, unscientific infrastructure development, including mega-hydroelectric projects, extensive road cutting, blasting, and deforestation. While the Western Ghats also face human encroachment, the scale and intensity of destructive developmental activities are far higher in the fragile Himalayan ecosystem.

Conclusion

The high frequency of landslides in the Himalayas is a natural consequence of its active tectonics, steep topography, and extreme weather, compounded by aggressive human development. Mitigating this hazard requires a shift toward eco-sensitive planning, the use of bio-engineering techniques for slope stabilization, and robust early warning systems tailored to fragile mountain terrains.