【摘要】 应用人工爆破地震波层析成像方法勘探地下速度结构。在海域、山地多种地质条件下进行了地震波层析成像方法定量勘探研究。依勘探目标体而异,通过设计震源频率、震源和观测仪器布局,提高观测分辨率,实现定量高精度速度结构勘探研究。勘探最大深度可达Moho界面;山地最高分辨率可达3 m。结果显示了该方法在近海区域和山区不同地质条件的适用性及不同勘探深度与勘探精度的实用性。在日本九州近海地域勘测中,同时使用了反射与折射2种走时资料,可以同时改善水平及垂向的分辨率。成像图显示了地下结构详细特征,如任意斜向的凹凸形状,或高角度逆冲错断构造,分辨率达到10 m。同时显示出这些复杂几何体的埋藏深度。结果表明,诸如地下断层形状,资源矿藏储舱结构异常体的复杂几何形状,都可期望在层析成像技术的勘探分辨能力之内。它对于地下结构研究,矿产资源勘探,工程环境地质研究都有重要意义。结果也显示了成像方法的运算收敛速度和计算稳定性在结构勘探中是适用的。更多还原

【Abstract】 The quantitative velocity surveys have been carried out by explosion seismic tomography in several geologic settings.According to object,high resolution surveys can be obtained by designing source frequency,spatial distributions of source and receiver.The results show that the explosion seismic tomography technique can perform structure surveys at different depths in the sea or mountain regions.The investigation depth can extend to the Moho discontinuity.The resolution can as high as 3 m/s in mountain region.The new travel time tomograpic technique combined by refraction and reflection has been employed to the survey in Kyusyu sea region,Japan.The P wave arrival times received from 15 seismic surveys were used in the structure analysis of the 2-D profile.The velocity structure obtained from the tomographic techniquey shows an evident lateral heterogeneity.The velocity abnormal areas of arbitrary shape,such as thrust fault,resource cabin structure,emerge in the contours.It implies that the tomographic technique can character complicate geological structures.The validity of the technique can be expected for the geological structure analyses,the environment engineering and resource explorations in the sea and mountain regions.The result shows the tomography technique has an acceptable computation convergence velocity and stability.更多还原