Evaluating Proxy-Based Site Response in Israel

Abstract

ABSTRACT Three alternative site-response models are developed, using two complementing predictors, accounting for both stiffness and depth effects. The analysis is based on a large database of velocity profiles and their associated calculated amplifications with respect to the local generic rock profile. The frequency of peak amplification—fpeak—is chosen to supplement VS30, after considering the predictability of eight different site proxies. The suggested models are continuous in terms of spectral periods as well as in terms of their predictor parameters—VS30 and fpeak. Model performance is evaluated in terms of the reduction in variability. For example, for a spectral period of T=0.5  s, using either one of the suggested models reduces the amplification variability from 0.4 to 0.18, whereas using VS30 alone reduces it only to 0.24. This improvement suggests that the addition of fpeak is a significant improvement in the midperiod range.