Application of direct current resistivity method to environmental and hydrological problems.


The direct current resistivity (DCR) method is a well-established geophysical method that is widely used in environmental, civil engineering, and hydrological investigations. DCR has the advantage of producing spatial and temporal images of the subsurface in two and three dimensions at relatively high resolution compared to those produced by other electrical methods. In the past few decades, DCR method has been applied in a variety of “conventional” near surface land and marine environments. This dissertation addresses approaches to expanding the utility of DCR in conventional environments and to applying it in three different unconventional and challenging environments. Following an introduction to the research in chapter one, results of a binning method applied to continuous resistivity profiling data in water reservoirs are presented in chapter two. Results reveal that the method is computationally efficient and suitable for lacustrine environments. In chapter three, the application of the DCR method on a deep-marine, near-bottom environment is evaluated. This study shows that it is possible to collect valid DCR data in deep-marine settings to detect shallow resistivity anomalies and to map their distribution within 100 m of the seafloor. In chapter four, an application of a time-lapse azimuthal DCR method to monitor bedrock joints and soil cracking on a vertisol-shale terrain is evaluated. It is demonstrated that vertical profiles of anisotropy have the potential to quantify the density and orientation of both soil cracks and bedrock joints. Chapter five presents a brief summary and conclusions of the research.

Direct current resistivity. Electrical resistivity method. Electrical resistivity. Tomography.