India has released its revised Seismic Zonation Map under the updated Earthquake Design Code (BIS, 2025), introducing major changes based on active faults, maximum possible events, tectonic settings, lithology, and ground-motion attenuation patterns.
Seismologist Vineet Gahalaut, former director of the National Centre for Seismology (NCS), said the updated mapping finally brings uniformity across the Himalayas. It corrects earlier underestimations of long-dormant but active fault lines—especially in the central Himalayas. The outer Himalayan belt has also been reclassified due to the possibility of ruptures extending southward toward the Himalayan Frontal Thrust.
Key Updates in the New Seismic Zonation
- Introduction of Zone VI:
A new highest-risk category, placing the entire Himalayan arc under Zone VI for the first time. Earlier, this region was split between Zones IV and V. - 4 Zones to New System:
Previously, India used four zones—II, III, IV, and V. The updated map reorganizes these with more scientific precision. - Boundary Towns Upgraded:
Any town situated between two zones will now automatically fall under the higher-risk zone. - Geology-Based Mapping:
The new map prioritizes geological and tectonic features instead of administrative borders.
India ‘s Updated Earthquake Zone Map
- 61% of India’s landmass now falls in moderate to high hazard zones (previously 59%).
- 75% of India’s population now lives in seismically active regions.
Implications of the New Seismic Map
- Increased push for retrofitting old structures in high-risk areas.
- Restrictions on construction over soft sediment zones or near active faults.
- Need for uniform, stricter building codes across all Himalayan states.
- Greater emphasis on disaster-resilient infrastructure nationwide.
Government Strategies for Earthquake Preparedness
- NDMA & SDMAs:
NDMA formulates national disaster policies, while SDMAs create and implement state-level disaster plans. - National Seismological Network:
Strengthens earthquake monitoring, research, and development of early warning systems.
The revised seismic map marks one of the most significant updates in India’s earthquake safety framework, aiming to enhance preparedness for future seismic threats.
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