Fig. 14

Checkerboard structure with an anomaly size of 80 km \(\times\) 80 km and resistivities of 10 (dark gray) and 100 (light gray) \(\Omega \,{\text {m}}\). The checkerboard structure was embedded in the lower crust layer (from a depth of 14.8 to 33.3 km in the layered-earth model shown in Fig. 2a). Three arrays of 25 MT stations (crosses), each with a size of 160 km \(\times\) 160 km (dashed frames), were placed at central (black), northeast (blue), and northwest (red) positions