Seismic Micro-Zonation of Panchkula City through Active Seismic and Passive Ambient Noise Measurements along with Response Analysis

ABSTRACT The present study focuses on site characterisation for Panchkula City, Panchkula District, Haryana, India, using various geophysical techniques to assess its seismic response. A total of 85 sites were investigated using the Horizontal-to-Vertical Spectral Ratio (HVSR) technique to determine their fundamental frequencies, which ranged from 1.56 to 18.75 Hz. The HVSR analysis indicates that these sites are capable of amplifying ground motion by approximately 2 to 3 times. Out of the 85 sites, 15 sites were further examined using the Multiple Simulations with one Receiver (MSoR) technique to get subsoil shear wave velocity information, which has been used to invert HVSR curves using a joint-fit-inversion technique to obtain a 1-D shear wave velocity (Vs) profile of each site investigated. To validate the 1-D Vs profiles, 12 sites were additionally surveyed using the Multichannel Analysis of Surface Waves (MASW) technique. Based on Vs profiles, the Panchkula city has been classified under soil class ‘D’ as per NEHRP classification, and Vs30 values vary between 243-308 m/s. The response analysis was also performed using simulated strong ground motion of magnitude 6.8 (mb). The study computed the natural periods, amplification characteristics, and spectral acceleration values for different building typologies. The SA varied from 0.32 to 0.51g, whereas the peak response frequency varied from 2-4 Hz. These results highlight the influence of thick, loose soil layers in amplifying seismic waves and increasing ground shaking intensity. The study provides critical data for assessing seismic hazards, guiding earthquake-resilient urban planning and contributes significantly to disaster risk reduction strategies.