Transient Acoustic Wavefields in Continuously Layered Media with Depth-DependentAttenuation: An Analysis Based on Higher-Order Asymptotics

摘要

A method is presented for the analysis of the space-time domain acousticwavefield in a continuously layered, lossy, isotropic fluid or equivalent fluid. The method is based on integral transformations and consists of three steps. First, a temporal Laplace transformation with a real and positive transform parameter is applied, which is followed by horizontal spatial Fourier transformations. Second, higher-order, WKBJ-like asymptotic representations are derived that form approximate solutions of the resulting transform domain problem. Third, the Cagniard-De Hoop method is employed for the transformation back to the space time domain. Numerical results are presented for reflections from halfspaces filled with a continuously layered, equivalent fluid with a depth-dependent 'constant-Q' loss behavior.