电成像与浅层地震联合在浅覆盖区隐伏断层探测中的应用

Application of Collocated Resistivity Tomography and Shallow Seismic Method to the Detection of Concealed Faults in Areas with Thin Covers

为了避免单一物探方法在地质反演解释中存在的多解性弊端,本文介绍了以电成像法为主、浅层地震反射波法为辅的综合物探方法对隐伏断层进行探测的应用实例,首先,通过电成像法查找断层破碎带的位置走向,然后利用浅层地震反射波法精确查明断层的产状、性质、位置及断距等地质参数,并对两种方法的探测成果进行综合对比分析,推断该隐伏断层为走向近东西向,倾向近南北向的正断层,断层落差约4.2m,其上断点埋深约17.9m。经钻孔验证表明,电成像与浅层地震联合方法在浅覆盖区隐伏断层探测中具有精确、可靠、经济的优势,该方法具有较强的应用价值。

Date of single geophysical methods often have multiple solutions in geological inversion interpretation. Collocated geophysical techniques can help solve this problem. This paper presents an application case of a comprehensive geophysical exploration which combines the resistivity tomography and the shallow seismic reflection to detect concealed fault. First,the resistivity tomography is conducted to identify the fault location,and then the shallow seismic reflection method is used to delineate its attitude,character,position and displacement. The results of resistivity tomography can enhance the reliability of shallow seismic reflection survey. At the same time,the shallow seismic survey can improve the accuracy of concealed fault detection,so the comparative analysis of result from the two methods permits more reliable and precise detection to hidden faults. The result shows that the concealed fault has the characteristics of normal fault,strike nearly EW,trend toward SN with displacement about 4. 2m,in addition,the depth of upper breakpoint is about17. 9mbelow the ground. Drilling data prove that the collocated resistivity tomography and the shallow seismic reflection method have an advantage of accuracy,reliability and economy in detecting concealed fault in areas with thin covers. This approach has a great practical value.