The Inversion Method Of Field-source Parameters To Regional Gravity Changes And Its Application In Sichuan-Yunnan

The field-source feature of regional gravity changes is one of the most important information to know the underground material structure and tectonic movement, and it is also an important means to research the geodynamic process, and is also a key technique to research the mechanism of earthquake preparation and seismogenic mechanism. In this paper, based on the regional gravity changes data, we use inverse technique to obtain characteristic parameters of field-source. On the basis of present gravity theoretical model, we choose Euler deconvolution technique to realize the inverse of gravity changes data.Firstly, we summarize euler deconvolution method and the improved euler deconvolution method of the recent years, and analyze two key problems of euler deconvolution, one is Structural Index(SI)and the other one is euler sliding window, and we also discuss how to solve the problems of divergent solutions and non-stable solutions. Then, we use vertical cylinder model and vertical hexahedron model to simulate gravity changes and gravity gradient changes, and we find that gravity gradient changes is more sensitive to the boundary of abnormal body than the gravity changes do, so it is easier to recognize the abnormal body. In order to realize the qualitative and quantitative investigation, we use the standard euler deconvolution method and improved euler deconvolution method to inverse the single anomaly source and combined anomaly sources. We find that those methods can outline the boundaries and locate the depth of abnormal bodies effectively, and we achieve the optimized SI and source-field parameters. We also use horizontal gradient filter to optimize the euler solution, and it do turn out that this method can remove a lot of divergent solutions. At last we process and analyze the 6 period of observed gravity changes during the time from year 2012 to 2014 of Sichuan-Yunnan region, and on the basis of parameter optimization we use three-dimensional euler deconvolution to realize the inverse of observed gravity data. Combined with the Ludian Ms 6.5 earthquake on Aug.3th,2014. It turns out that the results of euler deconvolution method is the same as the earthquake positions of Ludian earthquake, and the position are all focused on the Zhaotong fault.In addition, the depth of the euler deconvolution results which is 20±10km is consistent with the real source depth of Ludian earthquake.This paper shows that:euler deconvolution method is available to inverse and analyze the mobile regional gravity signals, and it can also be used to detect deep-seated materials movement, and then to outline the boundary of abnormal body.The utilize of euler deconvolution method in the inverse of mobile gravity data provides a new train of thought and method. But euler deconvolution has limitations, such as the divergent solutions and non-stable solutions. How to solve these problems is the main and further study of euler deconvolution method, and it also has a significant meaning to enlarge the use of euler deconvolution method in the use of gravity and magnetic data. The implication of the study can help to carry out the analysis and inverse of geophysics data, and also can contribute to provide a reference to understand the changes of mediators during the process of earthquake preparation and tectonic movement.