Fomel-Stovas’ Generalized Approximation - Model Study and Improvement

Reducing computation cost for raytracing in multi-layered anisotropic models is considered in this abstract. Fomel and Stovas suggested a five-parameter approximation that they named “generalized” because it reduces to several known three-parameter forms. Model tests, performed by the authors, showed that this generalized approximation provides very high accuracy. These results imply that it can be used in place of the exact moveout function in modeling, migration and traveltime inversion. However, detailed model study shows that for some models, this approximation leads to significant errors. I developed a new eight-parameter approximation that provides higher accuracy and can replace the exact traveltime function that requires numerical ray calculations for each receiver.