A study of damping factors in perfectly matched layers for the numerical simulation of seismic waves

When simulating seismic wave propagation in free space, it is essential to introduce absorbing boundary conditions to eliminate reflections from artificially truncated boundaries. In this paper, a damping factor referred to as the Gaussian damping factor is proposed. The Gaussian damping factor is based on the idea of perfectly matched layers (PMLs). This work presents a detailed analysis of the theoretical foundations and advantages of the Gaussian damping factor. Additionally, numerical experiments for the simulation of seismic waves are presented based on two numerical models: a homogeneous model and a multi-layer model. The results show that the proposed factor works better. The Gaussian damping factor achieves a higher Signal-to-Noise Ratio (SNR) than previously used factors when using same number of PMLs, and requires less PMLs than other methods to achieve an identical SNR.