New Seismic Zonation Map of India

India’s New Seismic Zonation Map now includes 61% of the land in moderate to high hazard zones. Read here to learn why the 2025 redesign marks a turning point in earthquake risk planning.

In 2025, India released a significantly upgraded Seismic Zonation Map as part of the revised Earthquake Design Code (BIS 2025), reflecting decades of scientific advances in seismology, tectonics, lithology, and probabilistic hazard assessments.

Update

The Bureau of Indian Standards (BIS) has withdrawn its revised IS 1893:2025 seismic code after concerns were raised by the Ministry of Housing and Urban Affairs (MoHUA).

Consequently, the earlier version IS 1893 (Part 1):2016 has been reinstated as the current applicable standard for earthquake-resistant design in India.

The decision highlights the challenges of balancing scientific advancements in earthquake risk assessment with economic feasibility and stakeholder acceptance.

Reasons for Withdrawal of the 2025 Code

The withdrawal followed concerns raised by MoHUA regarding economic, procedural, and consultation-related issues.

1. Increase in Construction Costs

According to estimates:

• 10-15% increase in building construction costs in high seismic zones
• Up to 50% cost increase for major infrastructure projects

Such cost escalation could significantly impact:

• Affordable housing projects
• Urban infrastructure
• Public sector construction programmes

2. Lack of Stakeholder Consultation

MoHUA noted that the revised code was finalized without adequate consultation with:

• State governments
• Construction industry stakeholders
• Urban planning authorities
• Infrastructure agencies

Given the large economic implications, broader consultation was considered essential.

3. Implementation Challenges

The revised standards would require:

• New structural designs
• Advanced engineering practices
• Increased construction materials

These changes could slow down ongoing projects and raise implementation difficulties across the construction sector.

Current Applicable Standard

As of March 2026, India follows IS 1893 (Part 1):2016.

Seismic Zonation of India:

India is divided into four seismic zones based on earthquake risk.

Approximately 59% of India’s land area is vulnerable to earthquakes.

New Seismic Zonation (2025)

The new framework represents one of the most comprehensive overhauls of India’s earthquake risk classification since independence, introducing a new highest-risk Zone VI, redrawing the boundaries of vulnerable regions, and refocusing planning norms around geoscientific realities rather than administrative lines on the map.

• The update comes at a time when rapid urbanisation, infrastructure expansion, and climate-related uncertainties, combined with India’s complex tectonic setting, demand a far more precise understanding of seismic risk.
• With the revised map, India acknowledges its exposure: 61% of its landmass now falls within moderate-to-high hazard zones, and 75% of its population lives in seismically active regions.
• The shift is not merely representational; it imposes accountability on state governments, builders, urban planners, and citizens.

Why a New Seismic Zonation Map Was Needed

India sits at the collision boundary of the Indian and Eurasian plates, one of the most active tectonic regions in the world.

The nearly 5 cm per year convergence rate continues to accumulate strain along the Himalayan arc, the Rann of Kutch, and other fault systems in the peninsula.

However, the previous zonation map, dating back over two decades, had major limitations:

• It relied heavily on historical earthquake catalogues, which underrepresent long-return-period megaquakes.
• It did not fully incorporate modern seismic attenuation models, fault mapping, or geodetic data from GPS and InSAR.
• Administrative boundaries, not geological realities, frequently determined the classification of districts.
• It underestimated the risk in regions where urban expansion on soft sediments and reclaimed land amplified seismic waves.

The 2025 map integrates advances in earth sciences and global best practices, particularly probabilistic seismic hazard mapping, to produce a far more realistic assessment of India’s earthquake risk.

The New Seismic Zonation (Withdrawn)

Introduction of Zone VI- The Highest Risk Category

For the first time, India now recognises a dedicated Zone VI, denoting extremely high seismic hazard.

• The entire Himalayan arc, from Jammu & Kashmir to Arunachal Pradesh, falls entirely within this zone.
• Under the previous system, the Himalayas were split between Zones IV and V, which diluted the severity of risk and created inconsistencies in construction norms across high-risk districts.
• The new map eliminates this ambiguity, mandating uniform, stringent seismic design standards for all Himalayan states.

Why Zone VI?

The Himalayan arc is capable of producing:

• Mw 8 or higher earthquakes
• Ruptures extending hundreds of kilometres
• Cascading impacts such as landslides, liquefaction, and river damming

India’s scientific establishment acknowledges this potential through the upgraded categorisation.

Boundary Towns Now Automatically Fall in Higher-Risk Zones

In many parts of India, previous zonation lines cut across towns, placing one side of the boundary in a higher-risk zone and the other in a lower one. The new BIS code removes such inconsistencies.

Any settlement on or near a zonal boundary is now assigned to the higher-risk zone, ensuring:

• Greater safety margins in construction,
• No loopholes for builders to exploit lower standards,
• Uniform enforcement in seismic-prone areas.

Hazard Mapping Focuses on Geology, Not District Borders

Unlike earlier maps, the new zonation is rooted in geological conditions, such as:

• Presence of active fault systems
• Subsurface lithology (hard rock vs. alluvium vs. reclaimed land)
• Maximum credible earthquake (MCE) scenarios
• Attenuation characteristics
• Strain accumulation from GPS-based geodesy

This approach is more scientifically defensible and aligns with global frameworks adopted by Japan, the USGS, and New Zealand.

India’s Earthquake Vulnerability

61% of India’s landmass is now classified as moderate to high hazard, which is up from the earlier 59%, reflecting improved understanding of seismic threats in:

• Northeast India
• Delhi-Aravalli region
• Kachchh
• Indo-Gangetic plains
• Western Ghats faults
• Deccan seismogenic zones

75% of India’s population lives in seismically active regions

because population density is highest in the Indo-Gangetic basin, Himalayan foothills, and coastal mega-cities.

This concentration heightens disaster risk, particularly where unregulated urban expansion and substandard construction practices prevail.

Implications of the New Zonation Map

The 2025 map is not just a scientific update; it is a policy nudge, an urban planning intervention, and a public safety mandate.

1. Retrofitting of Critical Infrastructure: High-risk areas, particularly Zone VI, will now require retrofitting of:

• Hospitals
• Schools
• Bridges
• Dams
• Power plants
• High-rise buildings
• Lifeline services (water, telecom, emergency facilities)

Retrofitting becomes unavoidable for older structures built under outdated codes.

2. Restrictions on Construction Over Soft Sediments and Active Faults: Urban sprawl across soft alluvial zones, Delhi, Guwahati, Jammu, Dehradun, and Patna, faces tighter scrutiny. These sediments amplify seismic waves up to 5-10 times, making even moderate quakes potentially destructive.

Cities will now have to halt or restrict:

• Construction on reclaimed lands
• Foundations over liquefaction-prone riverbanks
• Development along known active faults
• Unsustainable hillside expansion in Uttarakhand, Himachal, and Sikkim

3. Uniform Building Standards Across Himalayan States: Previously, seismic safety codes were inconsistently applied across Himachal, Uttarakhand, J&K, Sikkim, and the Northeast. The introduction of Zone VI eliminates ambiguity.

All Himalayan states will now be required to:

• Adopt the same stringent BIS norms
• Enforce disaster-resilient structural design
• Mandate earthquake-proofing for both public and private buildings

4. Urban Planning and Land-Use Zoning Reforms: Municipalities will be asked to integrate the new map into:

• City Master Plans
• Development Codes
• Environmental Impact Assessments
• Infrastructure design
• Slope stability and landslide risk mapping

Institutions Driving Earthquake Preparedness

1. NDMA: National Disaster Management Authority: NDMA sets the national framework for:

• Disaster risk reduction
• Retrofitting guidelines
• Preparedness and training
• Earthquake-resistant construction standards

2. SDMAs: State Disaster Management Authorities: SDMAs translate national policy into local action through:

• Hazard maps
• Building code enforcement
• Localised early warning protocols
• Capacity-building of first responders

3. National Seismological Network (NSN): India’s NSN, one of the largest in the world, monitors real-time seismic activity and supports:

• Early warning system development
• Fault mapping
• Ground motion modelling
• Scientific research on regional seismicity

As India moves toward a robust nationwide earthquake early warning system, NSN forms the scientific backbone.

4. National Centre for Seismology: The National Centre for Seismology is the nodal agency of the Government of India for monitoring earthquake activity and conducts seismological research in the country.

Way forward

India’s revised Seismic Zonation Map is a decisive step toward modernising disaster preparedness. But hazard maps alone cannot save lives. The real test lies in:

• Strict enforcement of BIS codes,
• Retrofitting legacy buildings,
• Public awareness,
• Integrating science into urban planning, and
• Proactive investment in risk reduction.

With 75% of its population living under seismic risk, India cannot afford complacency. The 2025 zonation map is both a warning and an opportunity: a scientific reconnection between how we build and the ground beneath our feet.

Related articles:

• India’s Earthquake Preparedness
• Important geophysical phenomena