Optimization of Electrical Geophysical Survey Design for Hydrogeological Applications and Subsurface Target Discrimination

Persistent Link:
http://hdl.handle.net/10150/265345
Title:
Optimization of Electrical Geophysical Survey Design for Hydrogeological Applications and Subsurface Target Discrimination
Author:
Goode, Tomas Charles
Issue Date:
2012
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
Geophysical imaging methods significantly enhance our knowledge of subsurface characteristics and their use has become prevalent over a range of subsurface investigations. These methods facilitate the detection and characterization of both metallic and nonmetallic subsurface targets, and can provide spatially extensive information on subsurface structure and characteristics that is often impractical to obtain using standard drilling and sampling procedures alone. Electrical imaging methods such as electrical resistivity tomography (ERT) have proven to be particularly useful in hydrogeologic and geotechnical investigations because of the strong dependence of the electrical properties of soils to water saturation, soil texture, and solute concentration. Given the available geophysical tools as well as their applications, the selection of the appropriate geophysical survey design is an essential part of every subsurface geophysical investigation. Where investigations are located in an area with subsurface information already available, this information may be used as a guide for the design of a geophysical survey. In some instances, no subsurface information is available and a survey must be designed to cover a range of possible circumstances. Yet, in other instances, there may be significant subsurface information available, but because of subsurface complexities, a geophysical survey must still be designed to cover a broad range of possibilities. Demonstrating the application and limitations of ERT in a specific field application, the first investigation presented in this document provides guidance for developing methods to improve the design and implementation of ERT surveys in a complex subsurface environment. The two investigations that follow present the development of a relatively simple optimization approach based on limited forward modeling of the geophysical response for both static and mobile surveys. This process is demonstrated through examples of selecting a limited number of ERT surveys to identify and discriminate subsurface target tunnels (with a simple cylindrical geometry). These examples provide insights into the practical application of the optimization process for improved ERT survey design for subsurface target detection. Because of their relative simplicity, the optimization procedures developed here may be used to rapidly identify optimal array configurations without the need for computationally expensive inversion techniques.
Type:
text; Electronic Dissertation
Keywords:
geophysical survey design; hydrogeologic monitoring; optimization; tunnel identification; Hydrology; capacitatively-coupled resistivity; ERT
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Hydrology
Degree Grantor:
University of Arizona
Advisor:
Ferré, Paul A.

Full metadata record

DC FieldValue Language
dc.language.isoenen_US
dc.titleOptimization of Electrical Geophysical Survey Design for Hydrogeological Applications and Subsurface Target Discriminationen_US
dc.creatorGoode, Tomas Charlesen_US
dc.contributor.authorGoode, Tomas Charlesen_US
dc.date.issued2012-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractGeophysical imaging methods significantly enhance our knowledge of subsurface characteristics and their use has become prevalent over a range of subsurface investigations. These methods facilitate the detection and characterization of both metallic and nonmetallic subsurface targets, and can provide spatially extensive information on subsurface structure and characteristics that is often impractical to obtain using standard drilling and sampling procedures alone. Electrical imaging methods such as electrical resistivity tomography (ERT) have proven to be particularly useful in hydrogeologic and geotechnical investigations because of the strong dependence of the electrical properties of soils to water saturation, soil texture, and solute concentration. Given the available geophysical tools as well as their applications, the selection of the appropriate geophysical survey design is an essential part of every subsurface geophysical investigation. Where investigations are located in an area with subsurface information already available, this information may be used as a guide for the design of a geophysical survey. In some instances, no subsurface information is available and a survey must be designed to cover a range of possible circumstances. Yet, in other instances, there may be significant subsurface information available, but because of subsurface complexities, a geophysical survey must still be designed to cover a broad range of possibilities. Demonstrating the application and limitations of ERT in a specific field application, the first investigation presented in this document provides guidance for developing methods to improve the design and implementation of ERT surveys in a complex subsurface environment. The two investigations that follow present the development of a relatively simple optimization approach based on limited forward modeling of the geophysical response for both static and mobile surveys. This process is demonstrated through examples of selecting a limited number of ERT surveys to identify and discriminate subsurface target tunnels (with a simple cylindrical geometry). These examples provide insights into the practical application of the optimization process for improved ERT survey design for subsurface target detection. Because of their relative simplicity, the optimization procedures developed here may be used to rapidly identify optimal array configurations without the need for computationally expensive inversion techniques.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectgeophysical survey designen_US
dc.subjecthydrogeologic monitoringen_US
dc.subjectoptimizationen_US
dc.subjecttunnel identificationen_US
dc.subjectHydrologyen_US
dc.subjectcapacitatively-coupled resistivityen_US
dc.subjectERTen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineHydrologyen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorFerré, Paul A.en_US
dc.contributor.committeememberMaddock, Thomas IIIen_US
dc.contributor.committeememberWinter, Larryen_US
dc.contributor.committeememberPoulton, Mary M.en_US
dc.contributor.committeememberMomayez, Moeen_US
dc.contributor.committeememberFerré, Paul A.en_US
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