India's New Seismic Zonation Map
Context:
India has released a radically updated seismic zonation map under the new Earthquake Design Code.
The update marks a significant shift in the country's understanding of earthquake exposure, driven by advanced scientific data
Key Highlights of the New Map
A seismic zonation map classifies different regions of India based on their earthquake hazard potential.
The updated map is issued by the Bureau of Indian Standards (BIS) as part of the revised Earthquake Design Code, 2025 (IS 1893)
For the first time, a highest-risk Zone VI has been introduced.
The entire Himalayan arc (previously split between Zones IV and V) has been placed in this new zone to reflect the uniform tectonic threat across the belt
The new assessment reveals that 61% of India's landmass now falls under moderate to high hazard zones (previously 59%).
The hazard profile of the southern peninsula remains broadly unchanged, with only minor scientific refinements
Scientific Basis & Methodology:
The map utilizes Probabilistic Seismic Hazard Assessment (PSHA)methods.
This approach incorporates data on active faults, potential magnitudes, and how ground shaking diminishes with distance, replacing the earlier reliance on historical epicentres
PEMA Index:
A new exposure window has been added using the Probabilistic Exposure and Multi-hazard Assessment (PEMA) method.
This accounts for population density and infrastructure concentration to assess the potential impact on communities, not just physical hazards.