Using a three-point difference approximation to improve absorbing boundary conditions for elastic wave modelling

Zaiming Jiang, John C. Bancroft, Laurence R. Lines

Absorbing boundary conditions are partial difference equations for which only forward or backward difference approximations instead of central difference approximations can be used. Usually two-point approximations are used for first order derivatives; however, three-point approximations result in less reflection from the computational boundaries. The two-point and three-point approximations are compared by means of illustrations.