Show simple item record

dc.contributor.advisorWait, James R.en_US
dc.contributor.authorMacInnes, Scott Charles.
dc.creatorMacInnes, Scott Charles.en_US
dc.date.accessioned2011-10-31T17:05:07Z
dc.date.available2011-10-31T17:05:07Z
dc.date.issued1988en_US
dc.identifier.urihttp://hdl.handle.net/10150/184322
dc.description.abstractA popular electrical exploration method is controlled source audiomagnetotellurics (CSAMT). Although the CSAMT method has had practical sucess, the theory used in CSAMT interpretation remains limited. The controlled source in CSAMT is a grounded electric dipole placed as far as is practical from the survey area. When the source-receiver separation is large enough, source fields can be adequately modeled by a single plane wave and conventional magnetotelluric interpretation methods can be used. Quite often however, data collected at lower frequencies can not be interpreted with magnetotelluric algorithms. If the electrical distance between source and receiver is too small, mathematical models must explicitly include the dipolar nature of the source fields to accurately model the data. Models which include a dipole source are limited. Most interpretation of CSAMT data is based upon horizontally layered models. In this dissertation, the model of plane layers excited by an arbitrary source is extended to include the effects of lateral changes in layer thickness. The method developed for modeling undulating interfaces mimics nature more accurately than plane-layered models, while preserving the utility of quick evaluation and insight lost to more general numerical methods. While the main emphasis here is on CSAMT applications, the theoretical results are valid for any source type. Topographic effects are modeled for plane wave and magnetic dipole sources. The effects of relief in basement topography on the response of a horizontal loop-loop system are computed and compared with scale-model measurements. CSAMT field data which can not be adequately explained by plane-layered models are analyzed using models with variable layer thickness. The correctness of the theoretical development is verified by comparison with physical measurements. The utility of the theory is illustrated by application to problems which can not be explained by plane-layered models.
dc.language.isoenen_US
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.subjectElectric prospecting.en_US
dc.subjectElectronics in geophysics.en_US
dc.titleLateral effects in controlled source audiomagnetotellurics.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.identifier.oclc701095418en_US
thesis.degree.grantorUniversity of Arizonaen_US
thesis.degree.leveldoctoralen_US
dc.identifier.proquest8809941en_US
thesis.degree.disciplineGeosciencesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.namePh.D.en_US
refterms.dateFOA2018-08-15T03:53:55Z
html.description.abstractA popular electrical exploration method is controlled source audiomagnetotellurics (CSAMT). Although the CSAMT method has had practical sucess, the theory used in CSAMT interpretation remains limited. The controlled source in CSAMT is a grounded electric dipole placed as far as is practical from the survey area. When the source-receiver separation is large enough, source fields can be adequately modeled by a single plane wave and conventional magnetotelluric interpretation methods can be used. Quite often however, data collected at lower frequencies can not be interpreted with magnetotelluric algorithms. If the electrical distance between source and receiver is too small, mathematical models must explicitly include the dipolar nature of the source fields to accurately model the data. Models which include a dipole source are limited. Most interpretation of CSAMT data is based upon horizontally layered models. In this dissertation, the model of plane layers excited by an arbitrary source is extended to include the effects of lateral changes in layer thickness. The method developed for modeling undulating interfaces mimics nature more accurately than plane-layered models, while preserving the utility of quick evaluation and insight lost to more general numerical methods. While the main emphasis here is on CSAMT applications, the theoretical results are valid for any source type. Topographic effects are modeled for plane wave and magnetic dipole sources. The effects of relief in basement topography on the response of a horizontal loop-loop system are computed and compared with scale-model measurements. CSAMT field data which can not be adequately explained by plane-layered models are analyzed using models with variable layer thickness. The correctness of the theoretical development is verified by comparison with physical measurements. The utility of the theory is illustrated by application to problems which can not be explained by plane-layered models.


Files in this item

Thumbnail
Name:
azu_td_8809941_sip1_m.pdf
Size:
4.281Mb
Format:
PDF
Description:
azu_td_8809941_sip1_m.pdf

This item appears in the following Collection(s)

Show simple item record