Describe earthquake belts in India.

Himalayan and north-eastern collision belt

• The Indian plate still pushes under Eurasia; strain along the Main Central Thrust, Main Boundary Thrust, and Himalayan Frontal Thrust makes the entire Himalayan arc the country’s highest seismic belt.
• Kashmir (2005 Muzaffarabad was across the Line), Kangra 1905, Bihar–Nepal 1934, Uttarkashi 1991, Chamoli 1999, and Nepal 2015 sit on this belt; Uttarakhand and Himachal are Zone V/IV in BIS terms.
• The north-east (Shillong 1897, Assam 1950) is a syntaxial knot of the Himalaya and the Indo-Burman ranges; much of the North-East is Zone V.
• Deep and shallow thrust earthquakes, landslides, and valley amplification are the associated hazards; this is a plate-boundary belt, not a random scatter.

Indo-Gangetic, western, and Kutch belts

• The Ganga–Brahmaputra alluvium can amplify shaking even when the hypocentre is in the Himalaya; parts of the northern plains, including belts of Uttar Pradesh and Bihar, sit in Zone III–IV because of this basin effect and hidden faults.
• The Delhi–Haridwar ridge and western Uttar Pradesh towns illustrate that a plain is not automatically safe.
• The Kutch rift and the western continental margin produced the 1819 Allah Bund and the 2001 Bhuj (Mw 7.7) earthquakes; Gujarat’s Kutch is Zone V.
• The Makran-linked western margin and the Murray Ridge system matter more for Pakistan–Iran, but they frame India’s western seismic story.

Peninsular and island belts

• Peninsular India is a stable shield with intra-plate events on old rifts and reservoirs: Koyna 1967 (triggered seismicity), Latur 1993, Jabalpur 1997, and occasional Andhra–Karnataka shocks.
• These are lower frequency than the Himalaya but high impact because masonry is unprepared; BIS still maps pockets as Zone II–III, with Koyna higher.
• The Andaman–Nicobar arc is a subduction belt of the Indian plate beneath the Burma microplate; the 2004 Sumatra–Andaman earthquake and tsunami showed that this island belt is among India’s most dangerous.
• BIS Zone V covers the islands and the north-east and Himalayan cores; Zone IV covers parts of the north belt and Gujarat; Zone III much of the northern plains and coasts; Zone II the more stable peninsula.
• A description of belts is therefore a map of plate boundary, failed rifts, and alluvial amplification, not a list of dates alone.