According to the dilatancy-diffusion earthquake model, there will be fluid motion into a dilatant zone prior to an earthquake. One possible consequence of this fluid motion is the generation of an electric potential anomaly by means of electrokinetic processes. A surface electric potential anomaly will not be produced unless there is a boundary separating regions of differing streaming potential coefficient and there is a component of pressure gradient parallel to this boundary. The magnetic anomaly produced by the current flow is calculated. It is shown for the case of an n-layered half space that the surface magnetic field will be identically zero no matter what the pressure distribution is. There will, however, be an azimuthal component of the magnetic field inside the earth.