A True-Amplitude Imaging Method Based on Gaussian Beam Migration and Demigration

Conventional seismic migrations are often suitable for structural imaging of the subsurface, but have quantitative limitations. We proposed an imaging strategy for obtaining true-amplitude imaging results within the framework of least-squares migration. Gaussian beam migration and demigration operators are developed to produce two images, which are used to estimate the approximate inverse of the Hessian in the imaging domain by introducing a non-stationary filter operator. By applying an image correction with the estimated inverse Hessian to a conventional Gaussian beam migration result, the resulting image is much closer to the true-amplitude image. Benefiting from the Gaussian beam propagator, which is a one-way beam propagator, the proposed method has more flexibility than the method based on two-way wave equations, and it can be adapted to higher frequency imaging with less computational cost compared to a two-way wave equation method. Some numerical examples are shown to demonstrate the effectiveness and efficiency of the proposed method.