Reproduced and modified from Figure A3 of Tichelaar and Hatchell [51]: The four components of the propagator matrix G diagonalized in eigen S-wave coordinates, over the 7 DSI computation receiver levels. The principal S-wave waveforms on the diagonal clearly show differing S-wave velocities, the eigen waveform G₂₂ (red) being faster than G₁₁ (blue). Time lines are superposed on the right side.