Structural Control of Fluid Flow: Offshore Fluid Seepage in the Santa Barbara Basin, California. Peter Eichhubl a,b, H. Gary Greene a,c, Thomas Naehr a, Norm Maher a a Monterey Bay Aquarium Research Institute, Moss Landing, CA 95039, USA; b Dept. of Geological and Environmental Sciences, Stanford University, CA 94305-2115, USA c Moss Landing Marine Laboratories, Moss Landing, CA 95039, USA Abstract Evidence of active and dormant fluid seepage in the Santa Barbara Basin is observed as active venting of gas and oil, bacterial mats, precipitates of authigenic carbonate, and mud and tar volcanoes. Fluid seepage occurs preferentially in the proximity to faults and faulted anticlines, and to slump scarps. Seepage next to faults and anticlines indicates that hydrocarbon migration and pore fluid expulsion is structurally controlled, with faults acting as preferred conduits for fluid flow across units of low matrix permeability.