Elastic Wave Field Numerical Simulation Based On Staggered Grid Finite Difference

Wave field numerical simulation is used frequently that is the important method of researching kinematics on seismic wave propagation and dynamic characteristics in earth medium, that is the foundation of seismic data processing. The quality of seismic wave forward modeling methods will directly influence the effect of simulation, precision of migration, practicability and adaptive capacity to the area of rapid velocity change and so on. Its core technology is solving wave equation to simulate the propagation of seismic wave in underground medium. To get the better result of seismic wave propagation, the artificial boundary reflections, stability, numerical dispersion and other problems must be considered in the numerical simulation.With the global energy scarcity, the exploration of underground resource is pushed into the spotlight. Because of the complexity of topography in China, the research of irregular surface and low-velocity layer and other complex structure is of grate important. Therefore the more objective and more accurate method is required to simulate seismic wave propagation and achieve the goal of geological exploration.Staggered grid higher order finite difference can substitute staggered grid for the general rectangle difference grid, obtain the difference finite of sufficient higher order spatial precision and timer resolution by means of half grid calculating. Firstly, the Taylor series was expanded and the staggered grid finite difference, absorbing boundary method based on the Eigen value analysis were used to get the difference format of equations for elastic waves and every boundary and angular point by analysis the request of stability and dispersion. This format could obtain arbitrary accuracy to implement the 2-D elastic wave numerical simulation with the staggered grid finite difference in various kinds of complex geologic model.This paper mainly studied the numerical simulation on horizontal earth surface, irregular surface layered media which have abruption, interlayer and other complex models, thought of the algorithm of feasibility and quality. The numerical experiment results indicate that this staggered grid finite difference could complete the elastic wave field simulation in various kinds of complex geologic model, weakened numerical dispersion markedly, had the characters of high simulation precision, strong commonality good stability and so on, could absorbing artificial boundary reflections effectively, attained good simulation effects of wave propagation. In addition, experiment had proved under the premise of promising precision, bigger mesh spacing could be used to improve calculative efficiency.