Figure A1--(a) velocity slice for row 23 (as in Figure 7d); (b) cummulative ray path length

Figure A1--(a) velocity slice for row 23 (as in Figure 7d); (b) cummulative ray path length in each model cell for actual inversion;(c) checkerboard model for resolution tests, velocity contrasts are ±10% and 50x50x10 km in dimension;(d) resolution results from checkerboard test, in percent P-wave perturbation.