A Broad View on the Interpretation of Electromagnetic Data (VLF, RMT, MT, CSTMT)
The resolution power of single Very Low Frequency (VLF) data and multi-frequency Radiomagnetotelluric (RMT) data in delineating conductive structures typical for the sedimentary cover and crystalline basement in Scandinavia is studied with a view to future developments of the technique to increasing...
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Uppsala universitet, Geofysik
2004
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ftuppsalauniv:oai:DiVA.org:uu-4146 2023-05-15T16:49:39+02:00 A Broad View on the Interpretation of Electromagnetic Data (VLF, RMT, MT, CSTMT) En bred syn på Tolkning av Elektromagnetiska Data (VLF, RMT, MT, CSTMT) Oskooi, Behrooz 2004 application/pdf http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4146 eng eng Uppsala universitet, Geofysik Uppsala : Acta Universitatis Upsaliensis Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1104-232X 959 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4146 urn:isbn:91-554-5925-0 info:eu-repo/semantics/openAccess Geophysics Airborne azimuthal anisotropy CSTMT distortion EM geothermal Hengill mineralization MT peaker resolution RMT tipper tensor VLF VLF Geofysik Doctoral thesis, comprehensive summary info:eu-repo/semantics/doctoralThesis text 2004 ftuppsalauniv 2023-02-23T21:44:19Z The resolution power of single Very Low Frequency (VLF) data and multi-frequency Radiomagnetotelluric (RMT) data in delineating conductive structures typical for the sedimentary cover and crystalline basement in Scandinavia is studied with a view to future developments of the technique to increasing the frequency range into the LW radio band. Airborne and ground VLF data are interpreted and correlated with RMT measurements made on the ground to better understand the resolution power of VLF data. To aid in this understanding single and multifrequency VLF and RMT responses for some typical resistivity structures are analyzed. An analytic model is presented for obtaining unique transfer functions from measurements of the electromagnetic components on board an air-plane or on the ground. Examples of 2D inversion of ground and airborne VLF profiles in Sweden are shown to demonstrate the quantitative interpretation of VLF data in terms of both lateral and depth changes of the resistivity in the uppermost crust. Geothermal resources are ideal targets for Electromagnetic (EM) methods since they produce strong variations in underground electrical resistivity. Modelling of Magnetotelluric (MT) data in SW Iceland indicates an alteration zone beneath the surface, where there are no obvious geothermal manifestations, in between Hengill and Brennisteinsfjoll geothermal systems. It suggests that a hydrothermal fluid circulation exists at depth. It also proves that the MT method, with its ability to map deep conductive features can play a valuable role in the reconnaissance of deep geothermal systems in active rift regimes such as in Iceland. A damped nonlinear least-squares inversion approach is employed to invert Controlled Source Tensor MT (CSTMT) data for azimuthal anisotropy in a 1D layered earth. Impedance and tipper data are inverted jointly. The effects of near-surface inhomogeneities are parameterized in addition to each layer parameter(s). Application of the inversion algorithm to both synthetic and field data shows ... Doctoral or Postdoctoral Thesis Iceland Uppsala University: Publications (DiVA) Hengill ENVELOPE(-21.306,-21.306,64.078,64.078) |
institution |
Open Polar |
collection |
Uppsala University: Publications (DiVA) |
op_collection_id |
ftuppsalauniv |
language |
English |
topic |
Geophysics Airborne azimuthal anisotropy CSTMT distortion EM geothermal Hengill mineralization MT peaker resolution RMT tipper tensor VLF VLF Geofysik |
spellingShingle |
Geophysics Airborne azimuthal anisotropy CSTMT distortion EM geothermal Hengill mineralization MT peaker resolution RMT tipper tensor VLF VLF Geofysik Oskooi, Behrooz A Broad View on the Interpretation of Electromagnetic Data (VLF, RMT, MT, CSTMT) |
topic_facet |
Geophysics Airborne azimuthal anisotropy CSTMT distortion EM geothermal Hengill mineralization MT peaker resolution RMT tipper tensor VLF VLF Geofysik |
description |
The resolution power of single Very Low Frequency (VLF) data and multi-frequency Radiomagnetotelluric (RMT) data in delineating conductive structures typical for the sedimentary cover and crystalline basement in Scandinavia is studied with a view to future developments of the technique to increasing the frequency range into the LW radio band. Airborne and ground VLF data are interpreted and correlated with RMT measurements made on the ground to better understand the resolution power of VLF data. To aid in this understanding single and multifrequency VLF and RMT responses for some typical resistivity structures are analyzed. An analytic model is presented for obtaining unique transfer functions from measurements of the electromagnetic components on board an air-plane or on the ground. Examples of 2D inversion of ground and airborne VLF profiles in Sweden are shown to demonstrate the quantitative interpretation of VLF data in terms of both lateral and depth changes of the resistivity in the uppermost crust. Geothermal resources are ideal targets for Electromagnetic (EM) methods since they produce strong variations in underground electrical resistivity. Modelling of Magnetotelluric (MT) data in SW Iceland indicates an alteration zone beneath the surface, where there are no obvious geothermal manifestations, in between Hengill and Brennisteinsfjoll geothermal systems. It suggests that a hydrothermal fluid circulation exists at depth. It also proves that the MT method, with its ability to map deep conductive features can play a valuable role in the reconnaissance of deep geothermal systems in active rift regimes such as in Iceland. A damped nonlinear least-squares inversion approach is employed to invert Controlled Source Tensor MT (CSTMT) data for azimuthal anisotropy in a 1D layered earth. Impedance and tipper data are inverted jointly. The effects of near-surface inhomogeneities are parameterized in addition to each layer parameter(s). Application of the inversion algorithm to both synthetic and field data shows ... |
format |
Doctoral or Postdoctoral Thesis |
author |
Oskooi, Behrooz |
author_facet |
Oskooi, Behrooz |
author_sort |
Oskooi, Behrooz |
title |
A Broad View on the Interpretation of Electromagnetic Data (VLF, RMT, MT, CSTMT) |
title_short |
A Broad View on the Interpretation of Electromagnetic Data (VLF, RMT, MT, CSTMT) |
title_full |
A Broad View on the Interpretation of Electromagnetic Data (VLF, RMT, MT, CSTMT) |
title_fullStr |
A Broad View on the Interpretation of Electromagnetic Data (VLF, RMT, MT, CSTMT) |
title_full_unstemmed |
A Broad View on the Interpretation of Electromagnetic Data (VLF, RMT, MT, CSTMT) |
title_sort |
broad view on the interpretation of electromagnetic data (vlf, rmt, mt, cstmt) |
publisher |
Uppsala universitet, Geofysik |
publishDate |
2004 |
url |
http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4146 |
long_lat |
ENVELOPE(-21.306,-21.306,64.078,64.078) |
geographic |
Hengill |
geographic_facet |
Hengill |
genre |
Iceland |
genre_facet |
Iceland |
op_relation |
Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, 1104-232X 959 http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-4146 urn:isbn:91-554-5925-0 |
op_rights |
info:eu-repo/semantics/openAccess |
_version_ |
1766039824399073280 |