Apparent resistivity and spectral induced polarization in the submarine environment

Relatively few investigations have employed electrical methods in the subma rine environment, which may be promising for mineral deposits or threatened by environmental problems. We have measured the electric field using both disk and bar electrodes in the sea water at three different levels: sea sur face, seven meters deep, and sea bottom at a depth of ten meters, employing a 2 m spacing dipole-dipole array with 7 array spacings of investigation, and 13 values of frequencies at steps of (2(N) hertz, N = -2, -1, 0. 1, 2.. .... 10). The measurement allowed the analysis of the electric field as a f unction of frequency and spacing, and of the spectral induced polarization. Modelling and interpretation of the apparent resistivity yielded a good fi t with previous drilling data. Analysis of the spectrum of the complex appa rent resistivity and the comparison with equivalent circuits, provided info rmation about the grain size, the mineral composition and the major induced polarization phenomenon occurring below the sea. Therefore the result of t he present research show the feasibility of measuring the variation of seaw ater resistivity in situ, as well as the resistivity of sea bottom sediment s.