Sensitivity analysis on measurement noise in the identification of soil properties from vertical array observation data

Abstract

SUMMARYThis study clarified the effects of measurement noise on identification of soil properties from vertical array observation of seismic waves. In order to evaluate the sensitivity of the unknown parameter with respect to error caused by noise, the amplitude of a transfer function was used to formulate the evaluation function in the frequency domain. Also the logarithmic amplitude was used to formulate the evaluation function and compare the sensitivity between the two types of amplitude expressions. A numerical experiment, based on a simple-structured ground model, showed that these evaluation functions produced satisfactory results which were in good agreement with identified results obtained by the measurement data contaminated by artificially generated errors. The present theory, when applied to actual earthquake records, proved useful in evaluating the influence of the non-linearity of soil characteristics.

Series expansion of complex ground amplifications with a sequence of simple transfer functions

“…More precise models of the site amplification based on the observed ground motions on horizontal or vertical arrays have been reported in many research papers [1,[13][14][15][16]. Most of the studies identify the corresponding physical velocity structures by applying a nonlinear inversion scheme, and they are regarded as the actual velocity structures beneath the sites.…”

“…Most of the studies identify the corresponding physical velocity structures by applying a nonlinear inversion scheme, and they are regarded as the actual velocity structures beneath the sites. One of the important problems is that the obtained results sometimes do not ensure a unique solution because of the local optimals [13,15]. This implies that estimated velocity structure may involve some uncertainty, and therefore, more reliable and specific models are required based on the observed ground amplifications.…”

Ground Transfer Functions of Seismic Waves Propagating between Vertical Array Measurement Points

“…;野沢・石田(1998) 3) ;佐藤 (2003) 4) ], S波の斜め入射を仮定した解析 [Satoh(2006) 5) ], 平滑化の影響[辻原他(1993) 6) ], 観測誤差の影響 [Kurita and Matsui(1997) 7) ], 誤差評価関数の扱い[辻原・澤田(2007) 8) ], 評価精度[辻原・沢田(1999) 9) ]のような最適化技術に係 わる基礎的な検討から，地盤減衰定数の評価 [Kobayashi et al(1992) 10) ;武村他(1993) 11) ;藤堂他(1995) 12) ;澤田他 (1998) 13) ;末冨他(2002) 14) ;辻原・澤田(2003) 15) ;佐藤他(2006) 16) ]や基盤面入射波の評価[佐藤他(1994) 17) ;永野他(2001) 18) ; 山添他(2004) 19) ] により，GL-22m, GL- …”