Fréchet kernels of SKS-splitting intensity S for the isotropic shear wave speed β and anisotropic parameters ɛ, δ and η=ɛ−δ in a model with a horizontal symmetry axis oriented in azimuth ϕ= 60°. When the axis of symmetry is either perpendicular (ϕ= 0°) or parallel (ϕ= 90°) to the propagation direction, no energy is scattered by either ɛ or δ into transverse-component and the corresponding ɛ and δ kernels vanish. Note that the sensitivity of SKS-splitting intensity to isotropic shear wave speed (top left) is much smaller than those to anisotropy parameters.