One-way propagators coupled with reflection/transmission coefficients for seismogram synthesis in complex media
基于耦合反射/透射系数单程波传播算子的地震波模拟研究

The one-way and one-return approximation is a multiple-forescattering-single-backscattering (MFSB) approximation. Compared with the full-waveform numerical methods, one-way approximation leads to a great saving of computing time and memory, which makes it possible to modelling wave propagation in long distances. In this article, we combine both the one-return and separation-of-variables approximations to develop a new one-way propagator coupled with reflection/transmission (R/T) coefficients for seismogram synthesis in complex media. The method is derived from establishing simultaneous generalized Lippmann-Schwinger equations in two adjoining heterogeneous layers followed by the separation-of-variables and one-return approximations. The resulting one-way propagator consists of two parts: the separation-of-variables screen propagator and the R/T operators that account for amplitude variations with incident angles across interfaces. The separation-of-variables screen propagator for one-way wave propagation accounts for wide angles in large-contrast media. The R/T coefficients are the implicit function of dip angle of geology subsurface, whose calculation is coupled with one-way propagation simulation in a natural manner. We benchmark the presented method against the full-waveform boundary element (BE) method for two numerical examples and a real geology structure, which shows that the presented method simulate the reflected waves well in travel time, amplitude, and waveform for various velocity contrasts across interfaces.