| 講演要旨(和文) | | 表層のS波速度構造の推定を目的に直線アレイと直線アレイの延長線上に設置した参照点を用いた微動測定を行った。初めに地震波干渉法解析を用いて参照点と直線アレイとの相互相関関数を計算した。その後、相互相関関数を擬似ショットギャザーとみなしてCMP解析により各CMP点における擬似CMPギャザーを計算した。各CMP点における擬似CMPギャザーに対してPhase shift法により分散曲線を求めた。得られた分散曲線を逆解析することにより各CMP点における1次元S波速度構造を得た。それを測線方向に並べることで2次元S波速度構造断面を得た。得られた結果はCCA法により得られたS波速度構造断面と大局的に整合する結果となった。 |
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| | 講演要旨(英文) | | Microtremors were observed to estimate the near-surface 2D S-wave structure using a linear array. First, by using seismic interferometry analysis, the cross-correlation function was calculated between a reference point (far from the linear array) and the stations in the linear array. Furthermore, CMP analysis was performed by assuming the obtained cross-correlation function as a pseudo-shot gather, and then a pseudo-CMP gather at each CMP point was calculated. Then, by using the obtained pseudo-CMP gathers, the phase velocity at each CMP point was calculated by the phase-shift method. The inversion of the phase velocities at each CMP pints was performed to obtain 1D S-wave velocity structures. Finally, these structures were integrated to obtain a 2D S-wave velocity structure. It is confirmed that the obtained S-wave velocity structure shows well consistent with the model that was constructed from the CCA method. |
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