Suppressing non-Gaussian noises with scaled receiver wavefield for reverse-time migration: comparison of different approaches.

ABSTRACT Numerical implementation of the gradient of the cost function in a gradient-based full- waveform inversion (FWI) is essentially a migration operator used in wave equation migration. In FWI, minimizing different data residual norms results in different weighting strategies of data residuals at receiver locations prior to back-propagation into the medium. In this paper, we propose different scaling methods to the receiver wavefield and compare their performances. Using time-domain reverse-time migration (RTM), we show that compared to conventional algorithms, this type of scaling is able to significantly suppress non-Gaussian noise, i.e., outliers. Our tests also show that scaling by its absolute norm produces better results than other approaches. [ABSTRACT FROM AUTHOR]