Electrical methods surveys in southern Arizona for hydrogeological investigations

Abstract

The central induction TEM and CSAMT strengths and weaknesses were analyzed at the San Xavier geophysical test site. TEM results indicate that the depth of investigation of the TEM sounding data is limited by the noise level. CSAMT data are contaminated by static shift effects due to shallow geological inhomogeneities or topography. CSAMT data are also contaminated by the transmitter overprint which depends on the geology beneath the transmitter dipole and the receiving stations. In the Miami Wash-Pinal Creek area of Arizona, where the groundwater contamination was to be studied by electrical methods, the complex resistivity method was first used. Results in the Miami Wash-Pinal Creek area show a trend which consists of a high-low-high trend in the resistivity/I.P. curves for soundings located in the contaminated zone and of an increase of the I.P. curve in the uncontaminated zone.