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Title: Spatial focusing of electrical resistivity surveys considering geologic and hydrologic layering

Abstract

Electrical resistivity tomography (ERT) has shown great promise for monitoring transient hydrologic processes. One advantage of ERT under those conditions is the ability of a user to tailor the spatial sensitivity of an ERT survey through selection of electrode locations and electrode combinations. Recent research has shown that quadripoles can be selected in a manner that improves the independent inversion of ERT data. Our ultimate interest lies in using ERT data along with measurements from other sensors, which typically can provide high-quality data from shallow regions of the subsurface, in a joint inversion. As a result, we do not consider the selection of quadripoles specifically for inde-pendent ERT inversion. Rather, we present an approach to focusthe spatial sensitivity of ERT surveys in specificsubsurface regions with the assumption that those data, when interpreted along with other measurements that are sensitive to those regions, will lead to more complete hydrologic characterization. Because we are interested in monitoring rapid processes, our approach is designed to efficiently identify optimal quadripoles. This is achieved by separating the optimization from the inversion grid, significantly reducing computational effort. We extend our previous work to consider the use of both surface and borehole ERT electrodes and to considermore » the impacts of horizontally layered electrical conductivity conditions. Results confirm the ability of the method to focus survey sensitivity while showing the importance of incorporation of prior knowledge of the subsurface electric conductivity structure in designing optimal ERT surveys.« less

Authors:
; ;
Publication Date:
Research Org.:
Idaho National Laboratory (INL)
Sponsoring Org.:
DOE - NE
OSTI Identifier:
912422
Report Number(s):
INL/JOU-05-01026
Journal ID: ISSN 0016-8033; GPYSA7; TRN: US200801%%853
DOE Contract Number:
DE-AC07-99ID-13727
Resource Type:
Journal Article
Resource Relation:
Journal Name: Geophysics; Journal Volume: 72; Journal Issue: 2
Country of Publication:
United States
Language:
English
Subject:
58 - GEOSCIENCES; BOREHOLES; ELECTRIC CONDUCTIVITY; ELECTRODES; FOCUSING; MONITORING; OPTIMIZATION; SENSITIVITY; TOMOGRAPHY; TRANSIENTS; electrical conductivity; hydrology; terrestrial electricity

Citation Formats

Gail L. Heath, Alex Fuman, and Ty P.A. Ferre'. Spatial focusing of electrical resistivity surveys considering geologic and hydrologic layering. United States: N. p., 2007. Web.
Gail L. Heath, Alex Fuman, & Ty P.A. Ferre'. Spatial focusing of electrical resistivity surveys considering geologic and hydrologic layering. United States.
Gail L. Heath, Alex Fuman, and Ty P.A. Ferre'. Thu . "Spatial focusing of electrical resistivity surveys considering geologic and hydrologic layering". United States. doi:.
@article{osti_912422,
title = {Spatial focusing of electrical resistivity surveys considering geologic and hydrologic layering},
author = {Gail L. Heath and Alex Fuman and Ty P.A. Ferre'},
abstractNote = {Electrical resistivity tomography (ERT) has shown great promise for monitoring transient hydrologic processes. One advantage of ERT under those conditions is the ability of a user to tailor the spatial sensitivity of an ERT survey through selection of electrode locations and electrode combinations. Recent research has shown that quadripoles can be selected in a manner that improves the independent inversion of ERT data. Our ultimate interest lies in using ERT data along with measurements from other sensors, which typically can provide high-quality data from shallow regions of the subsurface, in a joint inversion. As a result, we do not consider the selection of quadripoles specifically for inde-pendent ERT inversion. Rather, we present an approach to focusthe spatial sensitivity of ERT surveys in specificsubsurface regions with the assumption that those data, when interpreted along with other measurements that are sensitive to those regions, will lead to more complete hydrologic characterization. Because we are interested in monitoring rapid processes, our approach is designed to efficiently identify optimal quadripoles. This is achieved by separating the optimization from the inversion grid, significantly reducing computational effort. We extend our previous work to consider the use of both surface and borehole ERT electrodes and to consider the impacts of horizontally layered electrical conductivity conditions. Results confirm the ability of the method to focus survey sensitivity while showing the importance of incorporation of prior knowledge of the subsurface electric conductivity structure in designing optimal ERT surveys.},
doi = {},
journal = {Geophysics},
number = 2,
volume = 72,
place = {United States},
year = {Thu Mar 01 00:00:00 EST 2007},
month = {Thu Mar 01 00:00:00 EST 2007}
}
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