A study of the SP field produced by a polarized sphere in an electrically homogeneous and transversely anisotropic ground

摘要

The model of the polarized sphere, seated in an electrically homogeneous and isotropic half-space, has extensively been applied in the quantitative interpretation of self-potential (SP) anomalies, which are attributed to mineralized bodies, subsurface water or heat flow, or buried metallic bodies. Anisotropy, however, distorts the electric current flow and, consequently, the self-potential anomalies measured at ground surface. Important errors in the quantitative interpretation of the SP anomaly may be introduced, if electric anisotropy is not taken into account. In the present paper, the analytical expression for the SP field of a polarized sphere is derived, considering an electrically homogeneous and transversely anisotropic ground. The behavior of the corresponding SP curve is studied and the errors in the quantitative interpretation are estimated. Finally, quantitative interpretation methods are proposed, to determine geometrical and polarization parameters of the polarized body. The results and conclusions of this paper may be useful in environmental studies relevant to the detection of subsurface water/heat flow, fluid leakage and buried metallic bodies, or other hazardous environmental structures that can be simulated by a polarized sphere. The may also be useful in mineral exploration for graphite or sulfide ore bodies.