Development of analysis system for shallow subsurface by geophysical prospecting methods

最近，人们对地下，特别是地下几十米以下的浅部的兴趣正在迅速增长。城市开发建设、地下空间利用和防震减灾都需要地下信息，本研究旨在开发利用物探技术进行浅层地下结构解释的系统。通过综合几种地球物理方法独立分析的结果，将获得详细的地下信息。研究结果如下：1.提出了一种实用的隧道断面地震波正演预报方法。野外观测结果与场地地质构造吻合较好。2.提出了一种利用常规折射资料进行地震折射层析成像的方法。该方法能准确地成像浅层地下的速度结构。3.提出了一种电阻率数据的反演方法。4.提出了一种利用短周期微震阵列测量来准确估计浅层构造的方法。5.提出了一种利用微震水平和垂直运动的频谱分析来估计盆地基本结构的简单方法，大大提高了各种勘探方法的精度。因此，综合解释成为可能。盆地的地下结构将从基本结构到浅层进行解释。

Recently, interest in subsurface, especially shallow part of the earth down to several ten meters is rapidly growing. Subsurface information is required for urban development and construction, utilization of subsurface space and earthquake disaster prevention.This research aims to develop an interpretation system of shallow subsurface structure by use of geophysical prospecting techniques. By integrating the results analyzed independently by several geophysical methods, a detailed subsurface information will be obtained. The result of this research is as follows.1.A practical method for forward prediction of tunnel face by seismic wave was developed. The result of field data agrees well with geological structure of the site.2.A seismic refraction tomography method that uses conventional refraction data was developed. It can image the velocity structure of shallow subsurface accurately.3.An inversion method of electrical resistivity data was developed. It was applied to a subsurface environment monitoring.4.An accurate method to estimate the shallow structure by use of the array measurement of short-period microtremors was developed.5.A simple method to estimate the basic structure of basin was developed by use of spectral analysis of horizontal and vertical movement of microtremors.The accuracy of each prospecting method is greatly improved. Consequently, an integrated interpretation becomes possible. The subsurface structure of the basin will be interpreted from the basic structure to its shallow part.