Differentiate the causes of landslides in the Himalayan region and Western Ghats.

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Ghissu Editorial · Accepted Answer

Himalayan landslides stem from a young, tectonically active fold belt with fractured rock, earthquakes, cloudbursts and heavy infrastructure, while Western Ghats landslides stem from monsoon saturation of lateritic soil over hard rock, plantations and quarrying. The Wayanad debris flow of July 2024 killed more than 200 people.

**Introduction**

About 12.6% of India's land area is landslide-prone (GSI), concentrated in the Himalaya and the Western Ghats, whose slopes fail for different reasons.

**Contrasting Natural Causes**

SKETCH: comparison | Landslide Causes Compared
a: Himalaya
b: Western Ghats
- Young, rising fold belt :: Old, stable escarpment
- Earthquakes, cloudbursts :: Long monsoon downpours
- Fractured, sheared rock :: Wet soil over hard rock
- Rockfalls, debris slides :: Shallow debris flows
- Roads, tunnels, dams :: Plantations, quarries

1. **Tectonics**: The young, rising Himalaya is crushed along thrusts such as the Main Central Thrust and lies in Seismic Zones IV and V; the Ghats are an old, stable escarpment where quakes rarely trigger slides.
2. **Trigger and material**: Himalayan slides follow cloudbursts and glacial floods, as in Kedarnath (2013) and Chamoli (2021); in the Ghats, days of monsoon rain saturate lateritic soil, which slips over hard basalt as a debris flow.
3. **Relief**: Himalayan rivers such as the Alaknanda undercut gorge slopes, while the steep western scarp of the Ghats faces the monsoon head on.

**Contrasting Human Causes**

1. **Himalayan infrastructure**: Char Dham road cutting, hydropower tunnels and unchecked building load slopes, as the Joshimath subsidence of 2023 revealed.
2. **Ghats land-use change**: Tea, cardamom and rubber plantations replacing forests, and quarrying, which the Gadgil Committee (2011) sought to curb, loosen hillsides.
3. **Settlement on slopes**: Villages built on old debris-flow paths turn slides into disasters, as at Malin (2014) and Wayanad, where the July 2024 debris flow killed more than 200 people.

**Conclusion**

Himalayan landslides are mainly tectonic and event-driven, while Ghats landslides come from monsoon saturation and land-use change. Seismic zoning and regulated hill roads in the Himalaya, and rainfall-threshold early warning with forest restoration in the Ghats, are therefore the matching remedies for resilient hill communities.

Differentiate the causes of landslides in the Himalayan region and Western Ghats.

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