Apparent resistivity and spectral induced polarization in the submarine environment

Anais da Academia Brasileira de Ciências

Hercules De Souza²  Edson E. S. Sampaio¹ 

[1] ,Base Naval de Aratu Departamento de Magnetologia Salvador Bahia ,Brasil

关键词: complex apparent resistivity;    induced polarization;    forward modeling;    sea water;    resistividade aparente complexa;    polarização induzida;    modelagem direta;    água do mar;   

DOI  :  10.1590/S0001-37652001000300011

来源: SciELO

【 摘 要 】

Relatively few investigations have employed electrical methods in the submarine 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 surface, 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 (2N hertz, N = -2, -1, 0, 1, 2,.....10). The measurement allowed the analysis of the electric field as a function of frequency and spacing, and of the spectral induced polarization. Modelling and interpretation of the apparent resistivity yielded a good fit with previous drilling data. Analysis of the spectrum of the complex apparent resistivity and the comparison with equivalent circuits, provided information about the grain size, the mineral composition and the major induced polarization phenomenon occurring below the sea. Therefore the result of the present research show the feasibility of measuring the variation of seawater resistivity in situ, as well as the resistivity of sea bottom sediments.

【 授权许可】

CC BY   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License