Fourier Amplitude Spectrum at Arbitrary Points Estimated by Kriging Method

Abstract

This paper reports a method for estimating an acceleration Fourier amplitude spectrum (FS) on ground surface at arbitrary points using the transfer functions of the surface strata and the observation records of limited number of seismometers. The transfer functions at arbitrary points in Owari-asahi City are estimated by using a modified Kriging method based on the results of the seismic response analysis of the surface strata at 748 boring points using seismic waves on engineering bedrock caused by six earthquake scenarios. The acceleration FS on the surface at 642 boring points inside the city are estimated by using the proposed method based on only 20 observation records on the surface (estimated value). The result is compared to the acceleration FS estimated by the transfer functions and seismic waves on the engineering bedrock from earthquake scenarios at the same boring points (tentative observed value). It is found that the correlation coefficients per frequency between the estimated and tentative observed value at 642 points are no less than 0.5 any earthquake scenario.