ABSTRACTThe Born approximation is based on the assumption of small slowness perturbation. We investigate the limits of the Born approximation when applied to wave-equation migration velocity analysis and propose two new schemes which allow for larger slowness anomalies, while improving accuracy and increasing stability. The new schemes are based on linearizations of exponential functions using bilinear and implicit approximations, rather than the (Born) explicit approximation. We demonstrate the feasibility of our new operators on a synthetic example with highly variable background and strong slowness anomalies. |