Influences of local soil conditions for ground response in kolkata city during earthquakes.

Abstract

Ground motion while travelling from the bedrock to the ground surface, causing a change in amplitude and frequency of the seismic waves, and leading to amplification of ground motion have been seen in Kolkata in eastern India. One dimensional equivalent linear ground response analyses for some typical soil sites in Kolkata city of India have been implemented using SHAKE2000 for studying the effects of local soil conditions on the ground motions taking five different input motions having a wide variation in ground motion parameters. It is observed that the maximum horizontal acceleration at the ground surface is amplified by 4.1 times for 2001 Bhuj motion while the Fourier amplification factor and spectral acceleration at 5 % damping is observed to be 10.15 and 3.84 g, respectively at Rajarhat area due to 2011 Sikkim motion. The response spectrum curves obtained are useful for designers for evaluating the safety in designing infrastructures against earthquake forces in Kolkata city, especially in the absence of site specific data.