A study for estimation method of seismic design input motion considering the phase characteristics on scattered wave

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The objectives of this research are, 1) to develop a numerical method for analyze the effects of scattered wave occurred in the random media of bedrock and soil layers, and 2) to develop a estimation method for seismic design considering phase characteristics on scattered wave. The results of the research are summarized as follows;(1) A new numerical method is developed to analyze anisotropic scattering on the path based on the ray theory. The energy distribution obtained by the method is consistent with that by the conventional energy particle, method. The variance of the group delay time is found to be proportional to the squared hypocentral distance.(2) A new numerical method is developed to analyze the ground response considering the scattered wave in the random media based on R/T matrices method. The results of the method show that the effect of scattered wave occurred from the randomness of the media is smaller than that form the randomness of the boundary between soil layers.(3) A new numerical method to analyze the characteristics of wave propagation in a random media based on the spectral stochastic finite element method. The advantage of the method is to give the distribution shape as well. as the mean and variance value. The results of the method is consistent with that of Monte Carlo method. The computation time for the method is much smaller than that for the Monte Carlo method.(4) The characteristics of the response against the non-stationary ground motion defined by group delay time are examined. The result show the possibility to estimate the distribution of response value of SDOF system if the amplitude Fourier spectrum have a constant value.