Site Characterization vis-à-vis Probabilistic Seismic Hazard and Disaster Potential Modelling in the Himalayan and Sub-Himalayan Tectonic Ensemble from Kashmir Himalaya to Northeast India at the backdrop of the updated Seismic Hazard of the Indian Subcontinent

Abstract. The Indian landmass comprising of three broad morphotectonic provinces, namely the Himalaya and Tertiary mobile belts, Indo-Gangetic Foredeep and Peninsular shield have been jolted time and again by catastrophic earthquakes. The Socio-economic Risk Map of India generated by integrating vulnerable exposures with the IBC-compliant surface-consistent Probabilistic Seismic Hazard through an Analytic Hierarchy Process and expert judgement places the entire Himalayan stretch comprising of Kashmir Himalaya, Northwest India, Nepal together with Indo-Gangetic Foredeep, Bengal Basin, Darjeeling-Sikkim Himalaya, Northeast India and Bhutan in ‘High’ to ‘Severe’ Risk regime thus presenting this Tectonic Ensemble a typical case for site-specific study. Combined surface and downhole Geophysical and Geotechnical measurements classify this Tectonic Ensemble into site classes F/E, D4, D3, D2, D1, C4, C3, C2, C1, B and A with spectral site amplifications of 6.2, 4.8, 4.2, 3.9, 3.3, 2.58, 2.2, 1.87, 1.81, 1.4 and 1.2 respectively at 0.73–8.5 Hz frequency range thus facilitating surface-consistent probabilistic seismic hazard assessment in this Tectonic Ensemble exhibiting a PGA variation of 0.06 to 1.99 g whose structural impact is exhibited through SELENA-based building damage modelling using capacity spectrum method on the prevalent building types as ‘none’, ‘slight’, ‘moderate’, ‘extensive’ and ‘complete’ for all cities in the Ensemble.