Modify equivalent linear method of finding soil seismic response with magnitude and distance parameters

Abstract: One of important shortcomings of the traditional equivalent linear method（EQLM）is that for large input motions the magnification of high frequency components calculated is obviously lower than that observed. The defect may lead to a serious result of underestimating design ground motion parameters for key projects. So this important issue needs to be solved. Although it is reasonable to improve EQLM by using frequency dependent modules and damping ratios, it is not convenient to use and has great uncertainties. This article points out that, because magnitudes can affect spectra of ground motion, the method to improve EQLM by adjusting equivalent shear strain based on magnitudes may also be regarded as frequency dependent. Since distance can also affect the spectra, we suggest a method EQLM(M, R) to improve EQLM by the parameters of magnitudes and distances. An example of EQLM(M, R) is given to show that the above mentioned shortcoming of EQLM can be resolved to some extent.