Abstract
We examined grouping of site amplification factors using the H/V spectral ratio of microtremer to evaluate appropriate design ground motions in Tokyo Port, in which site amplification factors have been evaluated at sevelal strong motion sites using seismograms. In regard to the frequency range from 0.3-2.0 Hz, which affects the seismic performance of port structures, the peak frequency of the H/V ratio shows good coincidence with the peak frequency of the transfer fanction of the local soil layers which is controlled by the layer boundary with large impedance ratio. A simple scheme is illustrated for the grouping of site amplification factors using the amplitude of site amplification factors and the peak frequency of the H/V ratio of microtremer.
