Soil Amplification Studies for Ahmedabad Region

Abstract

The present paper is primarily concerned with identifying the areas in Ahmedabad region in which soil formations are prone to amplifying ground motions, as well as evaluation of amplification of peak ground accelerations due to soil using computer program ProShake for earthquake site response analysis. Based on the soil formation summary in Ahmedabad, a qualitative approach was employed to determine locations in Ahmedabad that are prone to ground motion amplification due to their soil formations, and a tentative map showing these areas was prepared. Acceleration amplification factors were obtained as the ratio of spectral accelerations at the top to those at the bottom of the soil formation. Amplification factors are presented for firm and weak sites. It was found that while for the firm sites, amplification factors reach only maximum values of 1.69, amplification factors in the weak sites may very well reach 4.26. This finding clearly confirms the effect of soil formation on amplification of ground motion.