Synthetic Examples of Self-Potential - Analysis of Flow Geometry

We study two numerical examples of self-potential (SP) signals produced by groundwater flow. First we briefly discuss the principle of numerical modeling of SP, which is based on (1) the solving of the diffusion equation for the hydraulic head distribution; (2) the calculation of sources of SP produced by groundwater flow; and (3) the solving of the Poisson equation for the electrical potential distribution. Then we analyze the SP response to the groundwater flow through a safe earth dam and we show that SP distribution is homogenous within the dam: electrical potential increases along the flow direction. For the case of the dam with damaged core the SP distribution becomes heterogeneous: a minimum of electrical potential clearly show the damaged area. We also present an example of SP distribution produced by vertical groundwater flow between two aquifers. We show that the vertical flow is pronounced in the SP signals measured on the ground surface and, therefore, the information about the vertical flow could be extracted from field SP data.