Fig. 8.From: Constraints on the three-dimensional thermal structure of the lower crust in the Japanese IslandsGeothermal gradient. The left panel (a) indicates geothermal gradients between the ground surface and the D90 depth obtained in this study. The right panel (b) indicates geothermal gradients measured at boreholes (Tanaka et al., 2004), the depth of which ranges from 300 and 6400 m and averages 1100 m.Back to article page