The computationally efficient phase-screen forward modeling technique is extended to allowudinvestigation of non-normal ray paths. The code is developed to accommodate all diffracted andudconverted phases up to critical angle, building on a geometrical construction method. The newudapproach relies upon pre-scanning the model space to assess the complexity of each screen. Theudpropagating wavefields are then divided as a function of horizontal wavenumber, and each subset isudtransformed to the spatial domain separately, carrying with it angular information. This allows bothudaccurate 3-D phase corrections and Zoeppritz reflection and transmission coefficients to be applied.udThe phase-screen code is further developed to handle simple anisotropic media. During phasescreenudmodeling, propagation is undertaken in the wavenumber domain where exact expressions forudanisotropic phase velocities are available. Travel-times and amplitude effects from a range ofudanisotropic shales are computed and compared with previous literature.
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