India sits on three crustal blocks with very different seismic histories, and earthquake risk in India is concentrated where the population is rising fastest. Examine the geomorphology and the policy response.
Subtopic: Geography · Physical — Geomorphology and Hazards
How to structure your answer
Introduction: The Indian subcontinent is built from three structural blocks — the active Himalayan thrust belt, the stable Peninsular shield (the Indian craton with Deccan Trap cover), and the Indo-Gangetic foredeep. Each has a distinct seismic signature.
Body — three dimensions: (1) Tectonic causes: ongoing collision of the Indian Plate moving north at 5 cm/year against the Eurasian Plate generates the Himalayan thrust; intra-plate stresses in the peninsula along the Narmada-Son lineament produced Latur (1993, M 6.4) and Koyna (1967, M 6.5). (2) Bureau of Indian Standards seismic zoning: Zone V (Kashmir, NE, parts of Gujarat, A&N) — very high risk; Zone IV (Delhi NCR, Mumbai metro, parts of UP, Bihar); Zone III (Chennai, Bengaluru), Zone II — low risk. Around 59% of India's land falls in Zone III or higher. (3) Policy gap: NDMA Earthquake Guidelines 2007 require structural compliance with IS 1893; municipal enforcement weak; National Building Code 2016 not adopted by all states; retrofitting limited; Kashmir 2005, Sikkim 2011, Doda 2013, Manipur 2016 illustrate continuing exposure. NDRF and INSAT-3DS provide post-event response.
Conclusion: The shift India needs is from response to risk-informed urban planning along the Himalayan front and in Zone IV megacities.
Written within the word limit
233 words · target 250 words · 14 min
Introduction:
The Indian subcontinent rides on three structural blocks — the active Himalayan thrust belt, the stable Peninsular shield with its Deccan Trap cover, and the Indo-Gangetic foredeep — each carrying a distinct seismic signature shaped by the Indian Plate's persistent northward drift at about 5 cm per year.
Tectonic causes: The continuing Indian-Eurasian collision drives the Main Boundary and Main Central thrusts; the Bhuj earthquake of 2001 (M 7.7, over 20,000 deaths) showed Kachchh rift reactivation, while Latur 1993 (M 6.4) and Koyna 1967 (M 6.5, reservoir-induced) exposed intra-plate stresses along the Narmada-Son lineament inside the supposedly stable peninsular craton.
Zoning and exposure: The Bureau of Indian Standards (IS 1893) places Kashmir, the North-East, parts of Gujarat and the Andamans in Zone V; Delhi NCR, Mumbai metro, parts of Uttar Pradesh and Bihar in Zone IV; Chennai and Bengaluru in Zone III. Around 59% of India's landmass falls in Zone III or higher, yet population growth is fastest precisely in Zone IV megacities such as Delhi NCR with over 30 million.
Policy gap: NDMA Earthquake Guidelines 2007 mandate IS 1893 compliance and the National Building Code 2016 prescribes retrofit norms; enforcement at municipal level is weak and the Code is not adopted across all states. Kashmir 2005, Sikkim 2011 and Nepal 2015 confirm continuing exposure; NDRF and INSAT-3DS only handle response.
Conclusion:
India must shift from post-event response to risk-informed urban planning — enforce IS 1893 retrofit along the Himalayan front, audit Zone IV megacity stock, and integrate microzonation into municipal approvals.
What an examiner expects to see
- Indian Plate movement c. 5 cm/year
- Three structural blocks — Himalaya, Indo-Gangetic foredeep, Peninsular shield
- Narmada-Son lineament as peninsular weakness
- BIS IS 1893 seismic zoning, four zones (II–V)
- 59% of Indian land in Zone III or higher
- Bhuj 2001 (M 7.7), Latur 1993 (M 6.4), Koyna 1967 (M 6.5)
- Kashmir 2005, Sikkim 2011, Nepal 2015 spillover
- NDMA Earthquake Guidelines 2007
- National Building Code 2016
- INSAT-3DS for disaster warning
Concrete cases, schemes and judgments
- Bhuj earthquake 2001, 20,000 deaths
- Latur earthquake 1993 in stable craton
- Koyna 1967 — reservoir-induced seismicity
- Nepal earthquake April 2015, M 7.8
- Delhi NCR in Zone IV — population over 30 million