The combined effect and stochastic simulation of strong ground motion for the sites with thick cover
JIANG Hui~(1,2),HU Yu-xian~(1), YU Yan-xiang~(1), WANG Xi-zhen~(1),LU Gui-lin~(2) (1.Institute of Geophysics, China Earthquake Administration. Beijing 100081,China; 2.Earthquake Administration of Xinjiang Autonomous Region.Urumqi 830011, China)
For the sites lacking the data of the boreholes and digital seismic records, "the combined effect of amplification and attenuation"(ab.'the combined effect') is difficult to estimate using usual methods. Relying on the prediction function of stochastic method, the combined effect factor (the product of the amplification factor and the high-frequency attenuation factor) can be estimated by the acceleration records of small-middle earthquake near source easily. The rectified result for the site nonlinearity shows that the combined effect factor is greater than 2 in 0.5～10 Hz and reaches 4 in 1.0～4.0 Hz. According to the combined effect factor we have determined, the stochastic simulation of the strong ground motions of the research region is consistent with the actual records.