地殻物性の異方性と弾性波動現象に関する地球工学的研究

本项目是一项基础性较好的勘探工作。在衍射层析成像中，利用射线路径层析成像结果，发展了散射波场的提取技术。在这个过程中，代表直达波场的参考道被精确地从观测数据中提取。其次，雷达层析成像被应用到地震优势区。通过对仪器方向灵敏度的修正，计算出了速度和衰减系数。最后，介电常数和泊松比推导出此分析。这一结果证明了雷达层析成像在绘制地下水路径方面的有效性。在野外实验中，衍射和射线路径层析成像应用于裂缝优势场，在小冈县Tanna地区。分别用这两种方法求出了速度分布。结果表明，射线路径法是有效的，但在绕射层析成像中仍然存在波场分离问题。在研究的最后阶段，提出了一种井间地震反射方法，用于绘制威尔斯井间的反射同相轴。初步结果表明了该方法的有效性。该方法的关键技术之一是具有精细速度分析的绕射叠加法。

This project is a well-based exploration work. In the diffraction tomography, the extraction technique of the scattering wave field was developed by the usage of ray-path tomogram results. In this process, the reference traces that represent the direct wave field are precisely extracted from the observed data. Next, the radar tomography was applied to the diorite dominant area. Both velocity and attenuation coefficient were calculated through the correction of instrument direction sensitivity. Finally, dielectric constant and poisson ratio were derived from this analysis. This results demonstrated the effectiveness of radar tomography for mapping underground water paths. In field experiments, diffraction and ray-path tomography were applied to the fracture dominant field, Tanna area in Shiauoka prefecture. The velocity distribution was derived from each method respectively. As the results, ray-path method proved to be useful, but the problem of wave field separation still remained in dffraction tomography. In the final stage of this research, a cross-well seismic reflection method was prosposed to mapping reflection events between wells. Preliminary results indicate the effective of the method. One of the key technique for this method is a diffraction stacking method with the detailed velocity analysis.