Lattice Spring Model for Irregular Interface Based on an Adaptive Location Strategy

The lattice spring model (LSM) is a novel method to simulate seismic wave propagation from a micromechanical perspective, which describes the elastic dynamics in complex media comprehensively and delineates the dynamic characteristics of the wavefield; however, it remains a great challenge to simulate wavefields at irregular interfaces with high accuracy. This work presents an adaptive location LSM (ALLSM) method to substantially improve the accuracy of simulated wavefields in a solid model. First, we design an algorithm to pick up the intersection coordinates of the internal interfaces with regular mesh. We obtain the intersection coordinates by solving the defined interface functions with different kinds of spring functions in the LSM. Then, we calculate the weights of springs with different elastic coefficients in the whole grid by the intersection coordinates. Finally, we obtain the real spring elastic coefficients in the presence of irregular interfaces by the arithmetic weighted average method and develop the corresponding interface position ALLSM to simulate the wavefield propagation mechanism in order to substantially improve the accuracy of the simulation. Numerical tests show that the improved ALLSM is more accurate than conventional LSM and second-order finite difference method (FDM). The accuracy of simulated wavefields is significantly improved about by 20%. The proposed method offers a new tool for wavefield simulation in complex media.