Assessing Seismic Vulnerability and Site Response in Varanasi City, India

Proximity of the highly stressed Faizabad ridge to Varanasi City and the unavailability of earthquake ground motion records necessitates a stochastic approach to study the deterministic seismic scenario of Varanasi city. The current study consists of 1D site response analysis of Varanasi city along Indus-Ganga plain. Details of boreholes for 30 sites across the city are used in the analysis. Synthesis of strong ground motions has been done for Azamgarh fault using stochastic finite fault model. The site response analysis results have been represented as surface acceleration time history (TH), response spectra and PGA contour. Estimated average response spectra at surface level are compared with IS-1893:2016 code which reveal that spectral acceleration values are presently underestimated at many places in Varanasi which would be a great risk from potential earthquakes in near future.