
TY  - JOUR
A1  - Dhu, Tania 
A1  - Heinson, Graham 
A1  - Joseph, John 
T1  - The hydraulic and electrical fractal dimension of regolith
JF  - ASEG Extended Abstracts
JO  - ASEG Extended Abstracts
Y1  - 2004
VL  - 2004
IS  - 1
SP  - 1
EP  - 4
KW  - 
UR  - https://doi.org/10.1071/ASEG2004AB030 
N2  - Electrical and electromagnetic (EM) geophysical data from a line or grid are usually converted into two- or three-dimensional resistivity models of the Earth. In regions of relatively uniform geology, variability of measurements are assumed to be random and Gaussian, such that the Earth models are found from a maximum likelihood approach. In this paper, we show that such variability is not Gaussian, and has a scale-length dependence, expressed as a fractal dimension. We argue that the fractal dimension of electrical and EM data is causally determined from Earth heterogeneity, which provides a link with hydraulic conductivity in porous and fractured media that also has a fractal dimension. This paper presents initial analyses of data from two sites within South Australia. NanoTEM time domain electromagnetic (TEM) data were collected at Tunkillia in the Gawler Craton with a target of identifying palaeochannels for gold exploration. Analysis of survey data revealed a good correlation between regions of low resistivity and high fractal dimension. On the other hand, a river-borne NanoTEM survey of the River Murray sediments showed much lower correlation. We conclude that analysis of the variability of EM data may provide useful additional constraints on subsurface properties. 
ER  -

