Fig. 8

Profiles of the Bouguer anomaly (a) and the topography of the basement surface (b). a The observed and interpolated residual Bouguer anomalies are represented by the open circles and cyan line, respectively. The interpolated residual Bouguer anomalies come from that of the Fig. 3d. The green line and red line represent the calculated Bouguer anomaly from the initial model (green in b) and the optimum model (red in b) using the 2D Talwani’s method. b The green line represents the initial model extracted from the gravity basement model (Fig. 7) along the survey line. The red line represents the optimum basement model obtained by selecting the best parameters (see Table 2). The black line represents the elevation of the ground surface. The origin of the x-axis is set as the tip of the Utsumi Fault in both a and b