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Complex resistivity measurements of confined rock

1985; American Geophysical Union; Volume: 90; Issue: B9 Linguagem: Inglês

10.1029/jb090ib09p07837

2156-2202

D. A. Lockner, J. D. Byerlee,

Earthquake Detection and Analysis

Complex resistivity was measured for samples of Westerly granite and Berea sandstone saturated with 0.01 M KCl aq . A four‐electrode technique was employed to make measurements over a frequency range of 10 −3 to 10 6 Hz and a confining pressure range of 0.2 to 200 MPa. When the electrical response was analyzed in terms of equivalent conductivity σ′ and relative permittivity K ′, both of these quantities varied more with confining pressure for the granite samples than they did for the sandstone. In addition, both rock types exhibited large low‐frequency dispersion of permittivity. While previous studies have measured the response of near‐dc conductivity to changes in pressure, measurements of pressure dependence of the full complex resistivity ρ * (ω) provide greater insight into earthquake‐related phenomena as well as induced polarization measurements and other remote sensing techniques.