Abstract:The forward modeling of seismic wavefields with the conventional finite difference method is constrained by fixed mesh spacing,and thus the mesh subdivision is inevitably inconsistent with the actual speed interface,which brings about problems such as stair diffraction in undulating interface and inaccurate travel time of reflection waves. The generalized finite difference method is a meshless algorithm based on Taylor function expansion and weighted least squares fitting. In this method,the partial derivative of unknown parameters in the differential equation is expressed as a linear combination of the function values of adjacent nodes,and suitable distribution forms of field nodes can be established according to different geological body models. Thus,it overcomes the problem of mesh dependence that the traditional finite difference method faces. In this paper,the non-uniform subdivision method which sets nodes along the layer is applied to make the generated nodes conform to the undulating surface or boundary. The test results of different models show that the generalized finite difference method can effectively solve the pro-blems of the spurious reflection and inaccurate travel time of reflection waves,with stability.
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