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| | Abstract | | In this study, we have developed a quasi-3D joint inversion tool using a non-linear least squares method, to estimate 3-D S-wave velocity structure from gravity, seismic, borehole and microtremor array data. In order to analyze gravity and microtremor array data simultaneously, the relation between density and S-wave velocity is assumed to follow empirical formulas given by Ludwig et al. 1970 or Matsuoka et al. 2000. In order to test the developed tool, we applied the joint inversion to the data acquired in the vicinity of Sapporo city. To perform a stable inversion, smoothing and flattening constraint conditions are applied to layer thickness and S-wave velocity between adjacent locations respectively. As a result of such analysis, horizontally smoothed velocity models are obtained. It is confirmed that the obtained velocity model shows well consistent with previous investigation. |
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