UPSC Mains 2021 GS1 Q4: Landslide Causes — Himalaya vs Western Ghats

The question asks for cause differences, not just a list. Structure the answer around distinct causal factors for each region.

Himalayan rock is geologically young, folded, and fractured by ongoing tectonic uplift. This makes it inherently weaker than older rock elsewhere.

Active thrust faults (Main Boundary Thrust, Main Central Thrust) generate frequent earthquakes. These shake loose material that is already unstable.

Snowmelt and glacial lake outburst floods add water at high altitudes. Combined with intense monsoon rain, this saturates slopes seasonally.

Very high relative relief means gravity acts on loose material over long, steep slopes. Altitude also limits vegetation cover at higher reaches.

The Western Ghats are an ancient escarpment of basalt and laterite, not a young fold range. Their instability comes from deep chemical weathering, not active tectonics.

Heavy tropical rainfall over centuries has weathered rock into a thick, weak lateritic soil layer. This overburden is prone to sliding once saturated.

The Western Ghats receive extremely heavy, concentrated monsoon rainfall on their windward slopes. Rainfall intensity, not seismicity, is the chief trigger here.

Conversion of forest to plantations (tea, coffee, rubber) and quarrying loosen slopes. Unlike the Himalaya, tectonic activity plays little role.

Both regions see roads, hydropower projects, and tourism infrastructure cut into slopes. This removes natural support in both cases, despite different underlying geology.

Himalayan landslides are geology- and seismicity-driven, intensified by monsoon. Western Ghats landslides are weathering- and rainfall-intensity-driven, with tectonics playing a minor role.

Himalayan mitigation needs seismic-aware construction codes and glacial lake monitoring. Western Ghats mitigation needs slope drainage, laterite stabilization, and regulating plantation-driven deforestation.