Application Of Finite Element Numerical Simulation To Shallow Seismic Prospecting

Numerical simulation of Seismic waves is an important foundation of exploration and theoretical seismology. It is not only an effective method to study the way of seismic wave propagating in various kinds of media in subsurface, but also an powerful tool for acquisition, processing and interpretation of seismic data in complex structure areas. Currently, shallow seismic prospecting is widely applied to solving problems of engineering geology. In this thesis, we attempt to reveal characteristics of seismic waves in different shallow small-scale models by a numerical simulation method of seismic wave equations.On the basis of analyzing the characteristic of main numerical simulation methods, we chose a finite element method to make seismic numerical simulation for shallow models with depth of hundred meters. The simulation method is of high precision and suitable for complex models. When making wave field simulation in shallow isotropic medium model, we synthetically analyzed the effect of dominant frequency of source, boundary condition, numerical parameters and so on, and also provided a process diagram. After analysis and comparison of the simulation results, we can conclude that simulation parameters can remarkably affect simulation results, such as computational accuracy and efficiency.We applied the numerical simulation method of seismic waves to shallow seismic prospecting in Yinchuan. Firstly, the field seismic data is processed and interpreted, and an initial geology model is obtained. Secondly, theoretical seismic records for the initial model are calculated by the finite element method. Thirdly, we compare the simulation data and actual ones for the same observation systems. The result shows that characteristics of main wave groups are quite similar, so to provide guiding assistance for optimizing data of observation system. All above prove that the finite element method is effective and feasible to do simulation of shallow seismic wave field, and it has broad application promise and valuable significance.