| 講演要旨(和文) | | 筆者らは，交通頻繁な道路に沿った河川堤防において，二次元リニアアレイ微動探査（2D-LAMS）が探査深度と交通振動の影響が少ないという面で，MASWよりも優位性があることを示した（北ほか，2013）．筆者らはこのときに得た微動データから，,空間自己相関法（SPAC）とTau-P変換法および地震波干渉法により表面波の分散曲線を求め，比較した．Tau-P変換法と地震波干渉法による分散曲線は，2D-LAMSの分散曲線と概ね一致していた．しかし，地震波干渉法による分散曲線は，低周波領域で実際のS波速度より速くなる可能性が指摘された．また，Tau-P変換法と地震波干渉法では，SPACに比べ，位相速度を安定的に求めることが困難であった．これらのことから，交通頻繁な道路に近い測線にあって，SPACを用いる2D-LAMSが受動式表面波探査として，他より有効な手法であることが確認できた. |
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| | 講演要旨(英文) | | The authors carried out a geophysical survey and data analysis using the 2 dimensional linear array microtremor survey method (2D-LAMS) on an earthen levee which was located along a heavily trafficked road. As the results, we had verified that 2D-LAMS had advantages in terms of its investigation depth and applicability under conditions of high levels of ground vibration noise (Kita et al, 2013). Using the same microtermor data obtained at the earthen levee with 2D-LAMS, we applied three data processing techniques, namely the Spatial Autocorrelation method (SPAC), the Tau-P transformation technique and the Seismic Interferometry (S.I.) technique, and then compared all three obtained dispersion curves. The dispersion curves obtained both by the Tau-P transformation technique and by the S.I. technique generally corresponded with those obtained by SPAC. It was suggested, however, that the phase velocities at low frequencies obtained by the S.I. technique would be faster than actual S-wave velocities. Neither the Tau-P transformation technique nor S.I. technique provided stable dispersion curves in comparison with SPAC which is used for 2D-LAMS. Consequently, we confirmed that 2D-LAMS is an advanced survey method as a passive source surface wave method, when the survey lines are set near busy roads. |
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