Transfer functions of the vertical and horizontal components of the displacement as a function of the normalized distance x/R at t= 5 s. We compare the SEM (stars) and a semi-analytical solution (circles) based on an expansion of Bessel functions (Sánchez-Sesma 1983) in the case of a hemispherical basin, for two frequencies: 5.76 Hz (η_P= 0.5) on the left and 8 Hz (η_P= 0.7) on the right.