| 講演要旨(和文) | | 本論では千葉県印西市において、地震計間隔7mの二重直線アレイで微動を観測し、その微動記録にもとづき,CCA解析と直線拡張SPAC解析を適用し，萬谷ほか（2018）で得られた２次元S波速度よりも深部の２次元S波速度の推定を試みた．CCA解析では通常のSPAC解析で得られた位相速度とほぼ同じ位相速度が検出されたが，より低周波の位相速度を検出することはできなかった．拡張SPAC解析では地震計間隔7m，14m，21m，28mの組み合わせの微動記録からレイリー波位相速度を算出し，2次元S波速度構造に換算した．測線中央付近では深度約50mでS波速度が約350m/s，測線距離約−70m，40m，136.5mでは深度60m程度においてS波速度が約230m/sを示しており，通常のSPAC解析で得られた２次元S波速度よりも深部の２次元S波速度を得ることができた． |
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| | 講演要旨(英文) | | In order to estimate 2-Dimensional S-wave velocities deeper than those obtained by Manya et al. (2018), we applied CCA analysis and 2-Dimensional Linear Array Microtremor Survey method to observed microtremors records. In CCA analysis, we obtained almost the same phase velocities as those obtained by normal SPAC analysis. However, phase velocities in the lower frequency range could not be obtained. In SPAC analysis, we calculated the Rayleigh wave phase velocities from microtremor records with distances of 7m, 14m, 21m and 28m. Then, we converted the Rayleigh wave phase velocities to 2D S wave velocity structures. Near the center of the survey line, it was found that the S wave velocity was about 350 m/s at a depth of about 50 m. It was found that the S-wave velocity was about 230 m/s at a depth of about 60 m at the survey line distances of about -70 m, 40 m, and 136.5 m. As a result, deeper 2-Dimensional S-wave velocities were deeper obtained than those obtained by ordinary SPAC analysis. |
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