Research And Application Of Integrated Geophysical Methods On Fault Reconnaissance

According to statistics, the number of the last century, died in the earthquake more than 160 million people, and then 50 years of economic losses caused by the earthquake of about 2,000 billion dollars. Since the founding, the occurrence of the Tangshan earthquake in China and the "5.12" Wenchuan earthquake in China's national economy have caused great losses. Frequent earthquakes and other natural disasters, man made to the important issue of how the earthquake disaster. Worldwide study showed that a large number of earthquake cases, history or current major surface rupture earthquakes occurred along the pre-existing active faults. Visible, in order to evaluate the seismic hazard of a region, to identify the location of fault, nature, the depth of structural relationship, deep tectonic setting is very important basic work.In recent years, carried out in our fault detection and seismic risk evaluation process, due to the detection region, generally regarded Quaternary cover, the vast majority of detecting the target fault buried fault, so a live geophysical fault detection means necessary and important. Quaternary cover the various regions are significant differences between the thickness of the surface complex geological conditions, combined with a variety of disturbances, determine the application of geophysical methods of difficulty and complexity, it is in this complex condition, the probe made good results. Practice has proved that it is conducting activities in the fault location and evaluation of space and deep tectonic environment of exploration and play a very important role. And with the progress of exploration, but also accumulated in fault detection of the experiences and lessons learned, promoting the development of geophysical disciplines.For the present study was to fault for its basic characteristics and environmental change, the evolutionary history of fault activity, the spatial structure of faults, active faults and trends, faults, the stress state and the mechanism of faults when the fault formed development of surface water, groundwater, land subsidence and building damage characteristic aspects. As for the spatial structure of the fault, the main use of geophysical methods. Geophysical exploration is an indirect means of detecting an object by studying the differences in physical characteristics to determine the spatial structure of the fault. Currently, researchers are mostly single geophysical method, so that the structure of fault detection is easy to form solutions, it is difficult to make precise details of the fault to understand.In this paper, "5.12" earthquake occurs after the plant JiangyouⅡseveral of the larger fault as the research object, the traditional geophysical methods (high-density resistivity method, shallow seismic reflection method) and nuclear geophysical methods (radon gas measurement) combine a variety of geophysical methods give full play to the strengths and expertise, conduct a detailed study of the fault.Firstly, the basic profiles of the study area-including geographical profile, geology, seismic site effects and to investigate the situation of the surface faults, and fault-related theories are described, and then introduces the high-density resistivity method, seismic reflection method and the method of radon measurement and the theoretical basis of the study area the fault of this geophysical field work and data processing methods, and finally compare the three exploration data analysis, cross-referencing, mutual authentication, are complementary in the study area conducted a comprehensive fault interpretation, ground faults identified in the study area developing depth, width and other characteristics of spatial development, and achieved good results.Studies have shown that high-density resistivity method, shallow seismic reflection method and the combination of radon measurements for the detection of underground space development characteristics of the fault is very feasible.In addition, this geophysical work, for a meaningful assessment of the site security, through the research established a set of fault detection of a variety of geophysical methods and techniques, survey research on the fault has a certain reference value, to address fault detection provides a theoretical basis and practical methods and techniques, has a wider relevance, resulting in certain economic and social benefits.