Zhaotong WAN - Subject Liasion, Tongji University Library, Siping Road ۱۲۳۹, Shanghai ۲۰۰۰۹۲, P.R.China
Qifeng LUO - Professor, Shanghai Institute of Disaster Prevention and Relief, Tongji University, Shanghai ۲۰۰۰۹۲, P.R.China

Since mutual transform between seismic intensity and magnitude is conventionally encountered in site-specific probabilistic seismic hazard analysis (PSHA), an often assumed transforming method between the two parameters is obtained using mathematical inversed functions, in that it may course inconsistency and contradiction, even to raise fallacy in the final PSHA results. This paper uses chi-square orthogonal regression of symmetric joint-elliptical intensity model in Southern Central China (SCC) to eradicate the paradox in mathematical and statistical derivatives. The difference between the estimated magnitude and intensity falls in the expected value, which means the modified intensity attenuation law is better than old model. The new attenuation model can be applied in micro-zonation and estimation of designed earthquake ground motions.