Fig. 2

Relationship between permeability and fluid pressure for A ductile and B brittle rock at 15 and 17 km depth. In A, the vertical dashed lines represent hydrostatic fluid pressure (\({p}_{{\text{hydrostatic}}}\)), ductile failure pressure (\({p}_{{\text{fail}},{\text{ductile}}}\)), and lithostatic pressure (\({p}_{{\text{lithostatic}}}\)), and the horizontal dashed lines background permeability in ductile rock (\({k}_{{\text{bkg}},{\text{ductile}}}\)). The grey region in A shows the area expanded in B. In B, the vertical dashed lines represent the hydrostatic fluid pressure and the brittle failure pressure (\({p}_{{\text{fail}},{\text{brittle}}}\)), with the grey region showing background depth-dependent permeability in brittle rock (\({k}_{{\text{bkg}},{\text{brittle}}}\)). In our models, permeability increases by two to four orders of magnitude relative to the depth-dependent value, resulting in maximum permeability of about 10^–16 m² (blue lines), 10^–15 m² (black lines), or 10^–14 m² (red lines)