Shimla, Dec. 2 -- In a sweeping overhaul of India's earthquake-risk classification, the Bureau of Indian Standards (BIS) has released the country's updated seismic zonation map, placing the entire Himachal Pradesh in the newly created and highest-risk category, Zone-VI.
The new designation marks a decisive departure from earlier classifications under IS 1893:2002, in which Himachal was divided between Zones IV and V.
The updated map - part of the Earthquake Design Code 2025 - is based on Probabilistic Seismic Hazard Assessment (PSHA), a methodology that incorporates deeper geophysical modelling, long-term fault behaviour and updated earthquake-recurrence data.
The shift is expected to reset the baseline for hazard identification, vulnera...