Fig. 4. RMS misfit maps show the misfit between the observed data and the calculated data of each site as a function of period. The calculated data are obtained (a) from the inverted model shown in Fig. 5; (b) by replacing the C1 conductor of Fig. 5 with a 300 m zone; and (c) by replacing the C2 conductor of Fig. 5 with a 300 m zone.