Disaster preparedness is the first step in any disaster management process. Explain how hazard zonation…

Question

Disaster preparedness is the first step in any disaster management process. Explain how hazard zonation mapping will help disaster mitigation in the case of landslides.

Ghissu Editorial · Accepted Answer

Hazard zonation mapping helps landslide mitigation by grading terrain into very high to low hazard zones that guide land use, infrastructure alignment, early warning and evacuation planning. The ISRO-NRSC Landslide Atlas of India (2023) finds about 12.6% of India's land prone to landslides.

**Introduction**

Preparedness begins with knowing where the ground will fail. The ISRO-NRSC Landslide Atlas of India (2023) finds about 12.6% of India's land prone to landslides, and hazard zonation mapping turns that risk into an actionable map.

**How Landslide Hazard Zonation Works**

SKETCH: flow | Making a landslide hazard map
- Geology, slope, relief layers
- Drainage, land use, rainfall
- LHEF factor ratings
- Total hazard score
- Very high to low zones
- Plans, codes, warnings

1. **Scientific rating**: IS 14496 (Part 2) rates lithology, structure, slope, relief, land cover and groundwater through the Landslide Hazard Evaluation Factor scheme.
2. **Graded, nested zones**: Ratings sort terrain into very high to very low hazard zones, mapped at 1:50,000 by GSI and needing 1:10,000 for towns.

**How Zonation Mitigates Landslide Disasters**

1. **Land-use regulation**: Zones decide where to forbid or restrict building; the Mishra Committee's 1976 Joshimath warning, ignored until the 2023 subsidence, shows the cost of inaction.
2. **Safer infrastructure**: Roads, railways and hydropower projects can avoid very high hazard belts or budget for slope protection in advance.
3. **Targeted early warning**: Sensors, like Amrita University's network in Munnar, can be concentrated in high hazard zones.
4. **Community preparedness**: Red-zone villages get evacuation routes and drills; Wayanad, among the most exposed districts in the atlas, suffered the Mundakkai-Chooralmala debris flow in 2024.

**Way Forward**

1. **Dynamic and binding maps**: Combine zonation with real-time rainfall data, make zones binding in master plans and clearances, and share them with panchayats.

**Conclusion**

Hazard zonation turns preparedness into a spatial plan of where not to build, what to reinforce and whom to warn, moving India from rescue to prevention as the Sendai Framework envisages.

Disaster preparedness is the first step in any disaster management process. Explain how hazard zonation mapping will help disaster mitigation in the case of landslides.

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