工学的基盤面と沖・洪積地盤面の地震動の変換係数-表層地盤の非線形性を考慮した最大地動, 応答スペクトル,非定常スペクトルの推定モデル-

Abstract

A simple method is developed for conversion between soil surface and rock surface earthquakemotion including nonlinear amplification/deamplification effects of soil layers overlying bedrock.Several simulated rock surface earthquake motions are generated for various combinations ofmagnitude and distance. The corresponding soil surface motions for these simulated earthquakesare calculated for typical soil layer models at Japanese strong motion observation stations. On thisbasis, a simple conversion factor, B, between soil surface and rock surface motion is proposed forpeak acceleration, peak velocity, response spectra, and intensity parameter of evolutionary powerspectrum. The conversion factor, B, is defined as a function of the soil parameter Sn whichrepresents the softness of surface layers, the depth to bedrock dp, and the earthquake motionintensity on rock surface.