Uttarakhand
National Seismic Hazard Map
- 28 Nov 2025
- 2 min read
Why in News?
The Bureau of Indian Standards has released an updated National Seismic Hazard Map, placing the entire Himalayan arc into a newly created highest-risk Zone VI, reflecting its extreme tectonic vulnerability and significantly revising national earthquake-risk assessment.
Key Points
- The new map categorises the complete Himalayan belt—from Jammu & Kashmir to Arunachal Pradesh—into Zone VI, the highest hazard classification, due to persistent tectonic stress along the Himalayan Frontal Thrust.
- About 61% of India’s landmass is now classified as moderate to high seismic-risk zones, requiring updated building codes, stricter land-use norms, and mandatory structural safety compliance.
- The updated zonation uses probabilistic seismic hazard modelling, incorporating new data on active faults, rupture behaviour, and strain accumulation, replacing older deterministic maps.
- Under the revised map, any town located on a boundary between two hazard categories will be shifted to the higher-risk zone.
- The seismic risk has increased not only in hill states but also in plains adjoining the Himalayas, including parts of Uttarakhand, Himachal Pradesh, J&K, Sikkim, Northeast, Bihar, UP, Haryana, Punjab and Delhi NCR.
Seismic Zones in India
- India’s earlier classification had Zones II, III, IV, V — with Zone V being the highest risk.
- The Himalayas are among the world’s most active collision zones, created by the Indian and Eurasian plate convergence (~5 cm/year).
- Major historical earthquakes: Kangra (1905), Bihar–Nepal (1934), Assam (1950), Kashmir (2005), Sikkim (2011), Nepal (2015).
- IS 1893, IS 4326, and National Building Code (NBC) govern seismic safety; the new map will necessitate extensive revisions.
