On the problem of determining the stochastic variation of the eigenfrequencies of layered soil

Often power spectra of several accelerogram at the same station show significant stable peaks during different earthquakes or after shocks. This indicate that the eigenfrequencies of the soil are mainly determined by the local soil system. In order to prove these empirical findings Monte Carlo simulation are carried out with random variables covering the influence of the location of the source and soil layers. The smoothing method as an analytical solution for this problem with the necessary extensions especially for random layering is presented. (author). 14 refs., 3 figs., 1 tab