Figure 6

Schematic illustration of the whole space and two half-space models. Schematic illustration of the whole space and two half-space models with four electrodes (after Ueda et al.2010). (a) A VEC-DC four-electrode configuration where the current and potential electrodes are placed in the whole space of resistivity ρ _a . (b) A four-electrode configuration for the double half-space model. In (b), ρ _w denotes seawater resistivity and ρ _s represents sub-seafloor resistivity. Electrodes C and P represent current and potential electrodes, respectively, with black circles. Electrode C^′ (open circle) denotes the image source of the current electrode C due to the seafloor.