Application of Nearly Perfectly Matched Layer with Second-order Acoustic Equations in Seismic Numerical Modeling

A crucial part of pre-stack reverse time migration is forward numerical computation of seismic wave propagation. However, there exist serious spurious reflections from truncated model edges during the simulation of wave propagation. In this work, we present a novel absorbing boundary layer named nearly perfectly matched layer (NPML) to suppress artificial reflections from model boundaries. Different from seismic numerical study on first-order partial differential equations, NPML with second-order acoustic equations is implemented here. Through checking snapshots of seismic wave propagation and seismograms, the numerical modeling results illustrate that the NPML is able to effectively absorb the outgoing waves at the truncated domain. Finally, our NPML algorithms are combined with the implementation of pre-stack reverse time migration to achieve accurate depth image of subsurface.