A stochastic method is proposed in this paper for evaluating short period ground motions based on synthesis method taking account of the randomness of inhomogeneous slip distribution of the source. RMS (root mean square) acceleration responses near source area were estimated by the random response theory using a non-stationary stochastic process as a Green's function. As an example analysis, RMS acceleration responses for the Nagamachi-Rifu fault were evaluated in Sendai area. RMS acceleration responses were good agreement with those by Monte Carlo simulation for the 500 samples synthesized using a stochastic Green's function. The expected value of maximum acceleration was estimated to be 3 to 4 times larger than the maximum value of RMS response for this example analysis. The expected maximum accelerations from RMS acceleration response on the pre-Quaternary stratum near the fault were discussed.
