Fig. 13

Map of estimated subsurface temperatures. Estimated temperatures at depths of 5 km (a), 10 km (b), 15 km (c), and 20 km (d) are shown. The subsurface temperatures obtained at each measurement point are interpolated by averaging filtering based on the nearest neighbor method. The grid size was set to 4 min, and the search area to 50 km. Based on the values of this grid, isotherms were described at 100 °C intervals. Note that since a simplified method is used to estimate the solidus temperature above 650 °C, the values in the high-temperature region have relatively large uncertainties at 15 km (c) and 20 km (d)