“…Two main kinds of solutions have been proposed for this purpose: absorbing boundary conditions (ABCs) (e.g. Clayton and Engquist, 1977;Reynolds, 1978;Liao et al, 1984;Higdon, 1986;Higdon, 1991) and absorbing boundary layers (e.g. Cerjan et al, 1985;Kosloff and Kosloff, 1986;Compani-Tabrizi, 1986, Sochacki et al, 1987Bérenger, 1994;Komatitsch and Martin, 2007;Sen, 2010, 2012).…”