Estimates of crustal permeability on the endeavour segment of the Juan de Fuca mid-ocean ridge

Observational studies of hydrothermal venting on the Endeavour segment of the Juan de Fuca Ridge place strong constraints on the spacing and area of vent fields, the depth of circulation, and the hydrothermal heat flux. A method is described to estimate a uniform crustal permeability from these parameters under the assumptions that upflow is confined to a narrow plume underlying each vent field and downflow can be described by potential flow into a point sink at the base of each plume. For a reasonable range of parameter values, the isotropic permeability of the Endeavour lies in the range 6 × 10−13 to 6 × 10−12 m2. A significant elongation of vent fields along-axis suggests that the permeability structure is strongly anisotropic, with the across-axis permeability about an order of magnitude lower than the permeability in orthogonal directions.