+publisher:"University of Adelaide" +contributor:("Heinson, Graham Stewart")

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University of Adelaide

1. Hatch, Michael A. Investigations of electromagnetic methods applied to the in-river and near-river environment along the Murray River, Australia.

Degree: 2011, University of Adelaide

URL: http://hdl.handle.net/2440/71505

► In the last decade more than 2500 km of the Murray River in southeastern Australia and its surrounding floodplains have been surveyed using a variety… (more)

▼ In the last decade more than 2500 km of the Murray River in southeastern Australia and its surrounding floodplains have been surveyed using a variety of geophysical techniques to assess the environmental impact of changing salinity conditions along the river. These have included a combination of ground-based and airborne electromagnetic (EM) techniques. Along the Murray River, particularly in the lower reaches, the near-surface conductivity ranges from being moderately resistive to highly conductive, with groundwater conductivities approaching that of seawater in many areas. Such conditions present challenges for the application of most EM techniques, particularly as the signal attenuates rapidly resulting in little signal penetration. For all EM and DC-resistivity techniques, careful selection of frequency range and/or system geometry is therefore necessary to collect information over depth ranges of interest. An understanding of tradeoffs between frequency range and/or system geometry, resolution, and penetration depth is arguably critical to technique selection at the outset of the survey, and to the application of appropriate data processing and interpretation procedures post-survey. This thesis examines and evaluates a number of geophysical techniques for their suitability in characterising the shallow subsurface beneath and adjacent to the Murray River. Results for three inductively and galvanically based geophysical techniques used to collect data in the in-river setting are compared over the same stretch of river. Two are variations on ground-based systems, adapted to collect data nearly continuously while being towed behind a boat. These are a time domain EM (TEM) system and a DC-resistivity system. The third is a high-resolution, helicopter-based, airborne EM (AEM) system. In this study, the AEM system was demonstrated to provide a similar horizontal resolution as that provided by river-based systems. In addition, although the river-based techniques were able to image to depths of approximately 20 m, the AEM system was able to image to approximately 25 m depth in highly conductive areas, and to approximately 60 m depth in more resistive areas. The AEM system was also able to collect data over floodplains adjacent to the river, providing contextual information where needed. A new methodology for processing ground penetrating radar (GPR) data collected over conductive ground is developed. As part of this development, the transition band in the EM spectrum is defined, using the loss tangent to define parameter boundaries. In the transition band (ranging from approximately 110 kHz to 57 MHz for typical soil conditions), both conductive and displacement currents are important as conduction mechanisms, and need to be accounted for when calculating phase velocity and skin depth. Data from three 25 MHz GPR traverses, varying in length from less than 3 km to more than 16 km, were collected over conductive floodplains. These data are processed using this new methodology, and interpreted in conjunction with ground TEM… Advisors/Committee Members: Heinson, Graham Stewart (advisor), Munday, Tim (advisor), School of Earth and Environmental Sciences (school).

Subjects/Keywords: electromagnetics; AEM; TEM; GPR; resistivity; conductivity; GPR phase velocity; permittivity; transition band

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APA (6^th Edition):

Hatch, M. A. (2011). Investigations of electromagnetic methods applied to the in-river and near-river environment along the Murray River, Australia. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/71505

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Hatch, Michael A. “Investigations of electromagnetic methods applied to the in-river and near-river environment along the Murray River, Australia.” 2011. Thesis, University of Adelaide. Accessed December 11, 2019. http://hdl.handle.net/2440/71505.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Hatch, Michael A. “Investigations of electromagnetic methods applied to the in-river and near-river environment along the Murray River, Australia.” 2011. Web. 11 Dec 2019.

Vancouver:

Hatch MA. Investigations of electromagnetic methods applied to the in-river and near-river environment along the Murray River, Australia. [Internet] [Thesis]. University of Adelaide; 2011. [cited 2019 Dec 11]. Available from: http://hdl.handle.net/2440/71505.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Hatch MA. Investigations of electromagnetic methods applied to the in-river and near-river environment along the Murray River, Australia. [Thesis]. University of Adelaide; 2011. Available from: http://hdl.handle.net/2440/71505

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Adelaide

2. Didana, Yohannes Lemma. Magnetotelluric imaging of conventional and unconventional geothermal resources.

Degree: 2016, University of Adelaide

URL: http://hdl.handle.net/2440/103456

► This thesis presents magnetotelluric (MT) imaging of the Tendaho conventional geothermal system in the Afar Depression in north eastern Ethiopia and the Habanero Enhanced Geothermal… (more)

▼ This thesis presents magnetotelluric (MT) imaging of the Tendaho conventional geothermal system in the Afar Depression in north eastern Ethiopia and the Habanero Enhanced Geothermal System (EGS) in the Cooper Basin in South Australia. The aims of this dissertation are twofold. The first was to characterize the resistivity structure of the Tendaho conventional geothermal system. This includes delineating fluid pathways and heat sources and determining the connectivity of geothermal localities in the Tendaho field using 2D and 3D resistivity models. The second aim was to investigate the viability of MT to monitor permeability enhancement in an unconventional EGS reservoir during fluid injection using continuous MT measurement at Habanero EGS in the Cooper Basin, South Australia. The 2D and 3D resistivity models of the Tendaho high temperature field reveal three main resistivity structures to a depth of 20 km. The surface conductive structure (typically B 10Ωm and > 1km thick) is interpreted as sediments, geothermal fluids or hydrothermally altered smectite clay. The underlying high resistivity structure is interpreted as Afar Stratoid Series basalts or chlorite-epidote alteration mineralogy. At a depth greater than 5 km, low resistivity is observed across the whole of the Tendaho geothermal field. This structure is inferred to be the heat source of the geothermal system. Based on geochemical and borehole information and a bulk resistivity from the resistivity model, a melt fraction of about 13% by volume has been estimated for the structure. The most striking feature in the 2D and 3D models is a conductive fracture zone in the basalts, which is likely to increase the permeability and temperature of the deep reservoirs in the basalts and provide an upow zone. Analysis of 3D resistivity models and the geochemistry of geothermal fluids suggests that the Dubti and Ayrobera geothermal localities at the Tendaho field are not connected. The inferred presence of a conductive fracture zone and shallow magma reservoirs make the Tendaho geothermal field a promising prospect for geothermal power development. An MT survey was conducted at Habanero EGS during stimulation of the Habanero-4 well, where 36.5ML of water with a resistivity of 13Ωm (at 25°C) was injected at a relatively continuous rate of between 27−53L/s into the EGS reservoirs at a depth of 4077 m. Analysis of pre- and post- injection MT responses showed possible conductive fractures oriented in a N/NNE direction. Apparent resistivity maps also revealed that the injected fluids likely propagated towards N/NNE direction. This result is consistent with the propagation direction of the dominant microseismic events, as well as the orientation of pre-existing N-S striking sub-horizontal fractures susceptible to slip on stimulation. The MT responses close to the injection point show on average a 5% decrease in apparent resistivity for periods >10 s. The main reasons for detecting only subtle changes in resistivity at the Habanero EGS is the screening effect of the conductive… Advisors/Committee Members: Heinson, Graham Stewart (advisor), Thiel, Stephan (advisor), School of Physical Sciences (school).

Subjects/Keywords: magnetotelluric monitoring; fluid injection; enhanced geothermal system (EGS); Habanero; Tendaho; Afar; Geothermal; partial melt; Ethiopia

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APA (6^th Edition):

Didana, Y. L. (2016). Magnetotelluric imaging of conventional and unconventional geothermal resources. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/103456

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Didana, Yohannes Lemma. “Magnetotelluric imaging of conventional and unconventional geothermal resources.” 2016. Thesis, University of Adelaide. Accessed December 11, 2019. http://hdl.handle.net/2440/103456.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Didana, Yohannes Lemma. “Magnetotelluric imaging of conventional and unconventional geothermal resources.” 2016. Web. 11 Dec 2019.

Vancouver:

Didana YL. Magnetotelluric imaging of conventional and unconventional geothermal resources. [Internet] [Thesis]. University of Adelaide; 2016. [cited 2019 Dec 11]. Available from: http://hdl.handle.net/2440/103456.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Didana YL. Magnetotelluric imaging of conventional and unconventional geothermal resources. [Thesis]. University of Adelaide; 2016. Available from: http://hdl.handle.net/2440/103456

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Adelaide

3. Robertson, Kate Elizabeth. Electrical resistivity structure of the Southeast Australian lithosphere.

Degree: 2016, University of Adelaide

URL: http://hdl.handle.net/2440/107378

► In its ability to retain signatures of tectonic events that enrich or deplete its fertilization state, the lithosphere holds the key to the tectonic evolution… (more)

▼ In its ability to retain signatures of tectonic events that enrich or deplete its fertilization state, the lithosphere holds the key to the tectonic evolution and history of Earth. Dewatering of the subducting slab leads to released fluids and induced melt which act to fertilize the overlying mantle in incompatible elements such as hydrogen. Conversely, rifting events lead to partial melting with fertile elements entering the melt, leaving behind a depleted lithosphere. Signatures such as these can remain in the lithosphere for hundreds of millions of years in the absence of further high temperature/melt events. Magnetotellurics (MT) is a passive geophysical tool that images the physical property of electrical resistivity and is capable of penetrating the entire lithosphere. MT is highly sensitive to minor interconnected conducting mineralogy and fluids, and thus is ideal for distinguishing between lithosphere of different degrees of enrichment. Additionally, the sensitivity to these minor phases means that fossil fluid pathways associated with the ascent of mineralising fluids and metals are detectable with MT. This is the cornerstone on which one of the main directions of the UNCOVER (Australian Academy of Science, 2012) initiative is based on- increasing the detectable signature of ore deposits by imaging the underlying fluid pathways and lateral dispersion of deposits. With these capabilities in mind, MT surveys were undertaken across western Victoria, Australia and the Ikara-Flinders Ranges and Curnamona Province in South Australia, Australia. The collection, processing and modelling of new MT sites were conducted for this thesis, with many other existing MT sites utilised to expand the dataset. In Chapter 2, 74 broadband (period of 0.001-2000 s) MT sites along the 1.2-5 km spaced east-west Southern Delamerian transect were processed, modelled and interpreted across western Victoria. The crust beneath the Delamerian Orogen has a heterogeneous resistivity structure, with low-resistivity fossil-fluid pathways stemming from Moho depths, intersecting an otherwise resistive upper crust. Serpentinite with interconnected magnetite is known to occur within the vicinity of the survey region, and conductivity measurements of hand samples indicate substantially lower resistivities for the serpentinised rocks, leading to the interpretation that serpentinite contributed to the low resistivity zones. Chapter 3 expands on the Southern Delamerian transect of Chapter 2 by modelling the transect using a 3D inversion code, along with four other pre-existing datasets which, when combined, create a 500 km continuous east-west transect. Importantly, this transect traverses the transitional zone between the Delamerian and Lachlan Orogens. The elusive boundary between these Orogens has most recently been interpreted as a gradual boundary within the Stawell Zone. Results from modelling show that the lower crust and shallow upper mantle of the Delamerian Orogen are at least an order of magnitude more resistive than the adjacent Lachlan… Advisors/Committee Members: Heinson, Graham Stewart (advisor), Thiel, Stephan (advisor), School of Physical Sciences (school).

Subjects/Keywords: electrical resistivity; lithosphere; magnetotellurics; AusLAMP; Research by Publication

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Robertson, K. E. (2016). Electrical resistivity structure of the Southeast Australian lithosphere. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/107378

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Robertson, Kate Elizabeth. “Electrical resistivity structure of the Southeast Australian lithosphere.” 2016. Thesis, University of Adelaide. Accessed December 11, 2019. http://hdl.handle.net/2440/107378.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Robertson, Kate Elizabeth. “Electrical resistivity structure of the Southeast Australian lithosphere.” 2016. Web. 11 Dec 2019.

Vancouver:

Robertson KE. Electrical resistivity structure of the Southeast Australian lithosphere. [Internet] [Thesis]. University of Adelaide; 2016. [cited 2019 Dec 11]. Available from: http://hdl.handle.net/2440/107378.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Robertson KE. Electrical resistivity structure of the Southeast Australian lithosphere. [Thesis]. University of Adelaide; 2016. Available from: http://hdl.handle.net/2440/107378

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Adelaide

4. Schnaidt, Sebastian. Improving uncertainty estimation in geophysical inversion modelling.

Degree: 2015, University of Adelaide

URL: http://hdl.handle.net/2440/111402

► Numerical inversion modelling is an integral part of geophysical data interpretation. Growing computational resources are used to invert ever-growing data sets and higher dimensional data.… (more)

▼ Numerical inversion modelling is an integral part of geophysical data interpretation. Growing computational resources are used to invert ever-growing data sets and higher dimensional data. However, models without meaningful uncertainty estimates are difficult to interpret reliably and limited attention has been paid to the advancement of model quality estimation techniques to keep up with the more sophisticated inversion schemes. The employment of meaningful uncertainty estimation methods is often hindered by the complicated implementation of those methods, and inadequate model quality estimators are frequently used. This project was aimed at the advancement of model uncertainty estimation, to enable a more common use. Two different approaches were developed, approaching the problem from different directions: Firstly, a bootstrap resampling approach for the qualitative estimation of model uncertainties is presented. The algorithm is characterised by an easy implementation and the fact that it can provide model quality estimation capabilities to existing inversion algorithms without requiring access to the inversion algorithm's source code. A given data set is repeatedly resampled to create multiple realisations of the data set. Each realisation is individually inverted and the variations between the generated models are analysed and visualised to generate interpretable uncertainty maps. The capabilities of the approach are demonstrated using the example of synthetic and real 2-D magnetotellurics data. Secondly, the multi-objective joint optimisation algorithm MOJO is presented, which aims to remedy the common shortcomings of classical joint inversion approaches. Joint inversion modelling is a powerful tool to improve model results and reduce the effects of data noise and solution nonuniqueness. Nevertheless, the classic joint inversion approaches have a variety of shortcomings, such as a dependency on the choice of data weights, optimising only a single solution resulting in inadequate uncertainty estimates, and the risk of model artefacts being introduced by the accidental joint inversion of incompatible data. MOJO is based on the concept of Pareto-optimality and treats each data set as a separate objective, avoiding data-weighting. The algorithm generates solution ensembles, which are statistically analysed to provide model uncertainty estimates. The shapes and evolutions of the solutions ensemble's distribution in objective space is dependent on the level of compatibility between the data set. The solution distributions are compared against a theoretical solution distribution corresponding to perfectly compatible data to estimate the compatibility state of any given objective-pair, allowing to distinguish between compatible and incompatible data, as well as identify data sets that are neither mutually exclusive nor sensitive to common features. MOJO's effectiveness was demonstrated in extensive feasibility studies on synthetic data as well as real data. The algorithm is adaptive and can be expanded to incorporate… Advisors/Committee Members: Heinson, Graham Stewart (advisor), Thiel, Stephan (advisor), School of Physical Sciences (school).

Subjects/Keywords: inversion modelling; uncertainty estimation; joint inversion; magnetotellurics; Research by Publication

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Schnaidt, S. (2015). Improving uncertainty estimation in geophysical inversion modelling. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/111402

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Schnaidt, Sebastian. “Improving uncertainty estimation in geophysical inversion modelling.” 2015. Thesis, University of Adelaide. Accessed December 11, 2019. http://hdl.handle.net/2440/111402.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Schnaidt, Sebastian. “Improving uncertainty estimation in geophysical inversion modelling.” 2015. Web. 11 Dec 2019.

Vancouver:

Schnaidt S. Improving uncertainty estimation in geophysical inversion modelling. [Internet] [Thesis]. University of Adelaide; 2015. [cited 2019 Dec 11]. Available from: http://hdl.handle.net/2440/111402.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Schnaidt S. Improving uncertainty estimation in geophysical inversion modelling. [Thesis]. University of Adelaide; 2015. Available from: http://hdl.handle.net/2440/111402

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Adelaide

5. Kirkby, Alison Louise. The resistivity and permeability of fractured rocks.

Degree: 2016, University of Adelaide

URL: http://hdl.handle.net/2440/111944

► Fracture permeability is necessary for the development of many unconventional energy resources, as they are often hosted in rocks with low primary permeability. The magnetotelluric… (more)

▼ Fracture permeability is necessary for the development of many unconventional energy resources, as they are often hosted in rocks with low primary permeability. The magnetotelluric (MT) method has previously imaged temporal resistivity changes associated with injection of conductive fluids into the subsurface. This thesis examines MT responses over two areas of the Otway Basin, Australia, to determine what characteristics of natural fractures can be imaged using MT. In addition, the resistivity and permeability of synthetic fractures and 3D fracture networks are modelled, to draw a link between the resistivity values that are measured and the permeability. One dimensional anisotropic MT inversions in the Koroit region, Victoria, central onshore Otway Basin, delineate strong resistivity anisotropy at 2-3 km depth with a north-northwest strike. The anisotropy strike is consistent with that of known fracture networks in the Koroit region, and the groundwater at this depth is known to be saline. Thus, the resistivity anisotropy is interpreted as fluid-_filled fractures and faults, reducing the resistivity in the north-northwest direction. In contrast, anisotropic inversions in the Penola Trough, western Otway Basin, reveal only minor anisotropy that is inconsistent with known fractures from coincident well image log and seismic data. Thus, an isotropic interpretation is consistent with the data here. Likewise, higher resistivities and lower permeabilities have been measured in wells in Penola, compared to Koroit. The resistivity and permeability of synthetic fractures filled with an electrically conductive fluid change non-linearly as the fractures are incrementally opened. A percolation threshold can be defined, below which the permeability and resistivity are close to the rock matrix values. At the percolation threshold, the permeability increases by three orders of magnitude or more over an aperture change of < 0.1 mm. The resistivity change depends on the ratio of the rock to fluid resistivity but is generally less than the permeability change, and occurs over a wider aperture range. Similar characteristics are observed in 3D fracture networks except that in networks, percolation is controlled by both the fault network density and fault connectivity. Many sparse networks will not percolate no matter how open the faults are. When the fault density is sufficiently high, a percolation threshold can be defined in terms of the mean fault aperture. At the percolation threshold, a change in mean aperture of 0.02 mm changes the permeability by four orders of magnitude and resistivity by a factor of four. The percolation threshold does not necessarily occur at the same aperture for different flow directions, so fault networks near their percolation threshold commonly show anisotropy in both resistivity and permeability. Therefore, not only are the MT responses in the Koroit region of the Otway Basin consistent with the presence of resistivity anisotropy due to pervasive open fractures and faults, but realistic fault networks… Advisors/Committee Members: Heinson, Graham Stewart (advisor), Holford, Simon Paul (advisor), Hasterok, Derrick (advisor), School of Physical Sciences (school).

Subjects/Keywords: magnetotelluric; electromagnetic; resistivity; conductivity; fracture; fluid; permeability; Research by publication

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APA (6^th Edition):

Kirkby, A. L. (2016). The resistivity and permeability of fractured rocks. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/111944

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Kirkby, Alison Louise. “The resistivity and permeability of fractured rocks.” 2016. Thesis, University of Adelaide. Accessed December 11, 2019. http://hdl.handle.net/2440/111944.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Kirkby, Alison Louise. “The resistivity and permeability of fractured rocks.” 2016. Web. 11 Dec 2019.

Vancouver:

Kirkby AL. The resistivity and permeability of fractured rocks. [Internet] [Thesis]. University of Adelaide; 2016. [cited 2019 Dec 11]. Available from: http://hdl.handle.net/2440/111944.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Kirkby AL. The resistivity and permeability of fractured rocks. [Thesis]. University of Adelaide; 2016. Available from: http://hdl.handle.net/2440/111944

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Adelaide

6. Maier, Rachel E. A petrophysical joint inversion of magnetotelluric and gravity data for enhanced subsurface imaging of sedimentary environments.

Degree: 2011, University of Adelaide

URL: http://hdl.handle.net/2440/69310

► An emerging field in geophysics is that of joint inversions, in which multiple technique data sets are analysed and inverted simultaneously. This helps to integrate… (more)

▼ An emerging field in geophysics is that of joint inversions, in which multiple technique data sets are analysed and inverted simultaneously. This helps to integrate the complementary data sets and reduce model ambiguity, common in single technique inversions. In this thesis a new implementation of a magnetotelluric (MT) and gravity 2D joint inversion scheme is developed based on a petrophysical approach. In sedimentary rock environments, electrical conductivity (which underpins the MT technique) can be approximated by Archie’s Law, whereas density (which underpins the gravity technique) can be derived from the porosity-density relationship. Since both expressions are themselves dependent on porosity, this petrophysical property provides the crucial link exploited by the 2D joint inversion. The 2D joint inversion approach devised here inverts directly for a porosity model, which is converted to resistivity and density models through Archie’s Law and the porosity-density relationship, then constrained (fitted) by the MT and gravity data. Thus, a single porosity model is produced that satisfies both data sets. By means of synthetic data inversions, it was established that the joint inversion is more effective in reproducing the true subsurface model than can be achieved by an MT or gravity inversion alone. Models produced by the joint inversion show improved placement of subsurface features and a greater accuracy of reconstructing the original subsurface (physical property) values. For optimal joint inversion results, broadband MT data should be used in favour of long period MT data, and the number of gravity stations should be greater than or equal to the number of MT stations. The joint inversion is particularly useful in extracting coherent information from noisy MT data when combined with good quality gravity data. While evaluating the MT and gravity compatibility, a new method was developed for evaluating the information contained in the MT Jacobian (sensitivity) matrix. The Renmark Trough in South Australia is an area of current geothermal interest for which multi-technique data (seismic, gravity, MT) exists. These field data were used to demonstrate and verify the effective use of the joint inversion in a practical real-world example. The Renmark Trough is a half graben structure with the Hamley Fault delineating the north-east boundary. At the Hamley Fault, the base of the trough is 3.5 km deep and rises gradually in a south-west direction. The inversion of the MT data alone produced a model inconsistent with seismic knowledge of the basement depths and geometries. In contrast, the joint inversion yielded a more geologically accurate image of the trough and faithfully reconstructed the basement depths and geometries. In the process of developing the joint inversion scheme, a 2D gravity inversion algorithm, based on the Occam maximum smoothness approach, was produced. This inversion algorithm demonstrated the inherent non-uniqueness of gravity interpretation by only placing strong density contrasts at the… Advisors/Committee Members: Heinson, Graham Stewart (advisor), Greenhalgh, Stewart A. (advisor), Tingay, Mark Robert Paul (advisor), School of Earth and Environmental Sciences (school).

Subjects/Keywords: join inversions; magnetotellurics; gravity

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Maier, R. E. (2011). A petrophysical joint inversion of magnetotelluric and gravity data for enhanced subsurface imaging of sedimentary environments. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/69310

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Maier, Rachel E. “A petrophysical joint inversion of magnetotelluric and gravity data for enhanced subsurface imaging of sedimentary environments.” 2011. Thesis, University of Adelaide. Accessed December 11, 2019. http://hdl.handle.net/2440/69310.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Maier, Rachel E. “A petrophysical joint inversion of magnetotelluric and gravity data for enhanced subsurface imaging of sedimentary environments.” 2011. Web. 11 Dec 2019.

Vancouver:

Maier RE. A petrophysical joint inversion of magnetotelluric and gravity data for enhanced subsurface imaging of sedimentary environments. [Internet] [Thesis]. University of Adelaide; 2011. [cited 2019 Dec 11]. Available from: http://hdl.handle.net/2440/69310.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Maier RE. A petrophysical joint inversion of magnetotelluric and gravity data for enhanced subsurface imaging of sedimentary environments. [Thesis]. University of Adelaide; 2011. Available from: http://hdl.handle.net/2440/69310

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Adelaide

7. Inverarity, Kent. Electrical geophysics of carbonate mound spring complexes of the South-Western Great Artesian Basin.

Degree: 2014, University of Adelaide

URL: http://hdl.handle.net/2440/92549

► Artesian mound springs occur along the south-western edge of the Great Artesian Basin, in northern South Australia, but their underground structure and relationship to faulting… (more)

▼ Artesian mound springs occur along the south-western edge of the Great Artesian Basin, in northern South Australia, but their underground structure and relationship to faulting is not well understood. This work aims to address this shortcoming with geophysical surveys over three mound spring systems (Beresford and Warburton Springs, the Bubbler Spring complex, and Freeling Springs), using a range of techniques: self-potential, magnetotellurics, and time-domain electromagnetics. The self-potential data contain elevated local responses to spring vents and seeps. Spatial correlation suggests that these responses are caused by flow related to springs. Similar responses also occur underneath ‘extinct’ springs, suggesting shallow subsurface discharge of aquifer water is still occurring. Little evidence was found for significant downward infiltration from spring tails. Modelling of time-domain electromagnetic and magnetotelluric data show that the confining Bulldog Shale, which is generally very conductive, contains slightly more resistive areas underneath springs and spring complexes, which may be related to a combination of carbonate buildup in the subsurface and more resistive aquifer water flowing to the surface. Magnetotelluric data and anisotropic 1D modelling suggests that fault zones exist under many of the mound springs, particularly at Beresford and Warburton Springs and the Bubbler Spring complex, with data consistent with models containing parallel vertical fault planes striking NW/SE. The models contain fault zones in the aquifer and the immediately underlying basement, suggesting that fluids may be sourced from the aquifer and deeper layers, and that faults may be acting as conduits through the aquitard. However, neither the faults nor the conduits to specific springs have been successfully imaged using the techniques employed here, suggesting that the conduits are narrow and present only a slight contrast in fluid resistivities. Advisors/Committee Members: Heinson, Graham Stewart (advisor), Hatch, Michael A. (advisor), Thiel, Stephan (advisor), School of Earth and Environmental Sciences (school).

Subjects/Keywords: magnetotellurics; self-potential; mound springs; Great Artesian Basin

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APA (6^th Edition):

Inverarity, K. (2014). Electrical geophysics of carbonate mound spring complexes of the South-Western Great Artesian Basin. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/92549

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Inverarity, Kent. “Electrical geophysics of carbonate mound spring complexes of the South-Western Great Artesian Basin.” 2014. Thesis, University of Adelaide. Accessed December 11, 2019. http://hdl.handle.net/2440/92549.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Inverarity, Kent. “Electrical geophysics of carbonate mound spring complexes of the South-Western Great Artesian Basin.” 2014. Web. 11 Dec 2019.

Vancouver:

Inverarity K. Electrical geophysics of carbonate mound spring complexes of the South-Western Great Artesian Basin. [Internet] [Thesis]. University of Adelaide; 2014. [cited 2019 Dec 11]. Available from: http://hdl.handle.net/2440/92549.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Inverarity K. Electrical geophysics of carbonate mound spring complexes of the South-Western Great Artesian Basin. [Thesis]. University of Adelaide; 2014. Available from: http://hdl.handle.net/2440/92549

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

University of Adelaide

8. Peacock, Jared Roy. Magnetotelluric monitoring.

Degree: 2012, University of Adelaide

URL: http://hdl.handle.net/2440/96465

► Enhanced geothermal systems (EGS) are emerging as an alternative energy supply, though progress has been slowed due to multiple uncertainties in subsurface processes. The most… (more)

▼ Enhanced geothermal systems (EGS) are emerging as an alternative energy supply, though progress has been slowed due to multiple uncertainties in subsurface processes. The most important unknown that needs to be overcome is how to spatially characterize injected fluids. Micro-seismic tomography can locate fractures opening caused by hydraulic pressure, but cannot directly discriminate whether that fracture is fluid filled or connected to other fractures. Magnetotellurics (MT) is sensitive to volumetric electrical conductivity contrasts with depth, specifically thermally enhanced saline fluids in a resistive host rock. Presented in this dissertation are 2 experiments designed for employing MT as a monitoring tool to characterize a fluid injection for the first stage of an EGS at Paralana, South Australia. The first experiment utilizes 11 MT stations set around the injection well continuously measuring 2 days before, 5 days during and 2 days after the fluid injection. Comparing the MT response estimated before the injection with subsequent responses estimated in 24 hour blocks demonstrates a temporal variation associated with injection of an electrically conductive fluid. Residual phase tensor analysis suggests that injected fluids migrated NE of the injection well in a preferred NNE direction, which correlates well with a concurrent micro-seismic array. The second experiment is a time-lapse MT survey that measures the MT response before and after the fluid injection by repeating the same 56 station array. The array contains 2 orthogonal lines of 22 stations each and 2 off diagonal lines of 6 stations each. Multiple pre-injection surveys were collected to ensure data precision and accuracy with a repeatability between surveys being on the order of 0.4 percent for periods above 1 second. However, in the MT dead band (1-20 s) repeatability is on the order of 3-4 percent. This is because of poor source signal and noise from a near by pipeline. The post-injection survey was collected a week after the injection finished and repeatability between pre and post-injection at high frequencies is on the order of 1 percent. Residual phase tensor analysis again suggest fluids propagated NE of the injection well but mostly into an existing fracture network trending NNE. These experiments suggest that MT can be used as a monitoring tool for a fluid injection, but care must be taken in collecting precise and accurate data as well as a detailed analysis of what can cause an anomalous MT response. Residual phase tensor analysis proves to be the most useful representation of the MT response because it provides directionality and is insensitive to near surface distortions. Finally, it is suggested that a dense grid of MT and micro-seismic measurements be collected as complimentary pairs to fully characterize a fluid injection. Advisors/Committee Members: Heinson, Graham Stewart (advisor), Thiel, Stephan (advisor), Hand, Martin Phillip (advisor), School of Earth and Environmental Sciences (school).

Subjects/Keywords: enhanced geothermal systems; phase tensor; magnetotellurics; monitoring

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Peacock, J. R. (2012). Magnetotelluric monitoring. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/96465

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Peacock, Jared Roy. “Magnetotelluric monitoring.” 2012. Thesis, University of Adelaide. Accessed December 11, 2019. http://hdl.handle.net/2440/96465.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Peacock, Jared Roy. “Magnetotelluric monitoring.” 2012. Web. 11 Dec 2019.

Vancouver:

Peacock JR. Magnetotelluric monitoring. [Internet] [Thesis]. University of Adelaide; 2012. [cited 2019 Dec 11]. Available from: http://hdl.handle.net/2440/96465.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Peacock JR. Magnetotelluric monitoring. [Thesis]. University of Adelaide; 2012. Available from: http://hdl.handle.net/2440/96465

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

9. Rivera-Rios, Aixa Maria. Multi-order vector finite element modeling of 3D magnetotelluric data including complex geometry and anisotropy.

Degree: 2014, University of Adelaide

URL: http://hdl.handle.net/2440/85200

► This thesis presents the development of a computational algorithm in Fortran, to model 3D magnetotelluric (MT) data using a Multi-order Vector Finite Element Method (MoVFEM)… (more)

▼ This thesis presents the development of a computational algorithm in Fortran, to model 3D magnetotelluric (MT) data using a Multi-order Vector Finite Element Method (MoVFEM) to include complex geometry (such as topography, and subsurface interfaces). All the modules in MoVFEM have been programmed from the beginning, unless specified by referencing the libraries used. The governing equations to be solved are the decoupled electromagnetic (EM) partial differential equations for the secondary electric field, or the secondary magnetic field, with a symmetric conductivity tensor to include anisotropy. The primary fields are the solution of a plane-wave within the air domain. Two boundary conditions are implemented, namely the Generalized Perfect Matched Layers method (GPML) and Dirichlet boundary conditions. Three Dirichlet boundary schemes are applied, first considering zero EM fields at the boundaries of the computational domain; secondly, considering the boundaries as homogeneous Earth; and finally, considering the boundaries as a layered Earth. Two formulations of GPML are implemented in this algorithm, firstly the original GPML formulation and secondly, the GPML parameters are modified for the MT and Controlled Source Electromagnetic (CSEM) problem. High-order edge-elements are defined based on covariant projections, and mixed-order edge-elements for hexahedra. The vector basis functions are defined for linear elements (12 edge-elements), quadratic elements (36 edge-elements), and Lagrangian elements (54 edge-elements). By this definition, the vector basis will have zero divergence in the case of rectangular elements and relatively small divergence in the case of distorted elements. The validation of this computational algorithm is performed with a homogeneous Earth, where the analytic solution of the MT problem is known. In the validation, the convergence of the solution is analyzed for different grid spacing and for different element-orders with Dirichlet boundary conditions. High-order elements produce accurate solutions with larger spacing than the fine grid needed for linear-order elements. After the convergence analysis, the solution obtained with all the proposed boundary conditions, and edge-element orders are compared for one frequency, and for a frequency range. In the homogeneous Earth, Dirichlet boundary condition presents backward reflections from the boundaries of the computational domain to the center of the model. Both GPML formulations produce more stable solutions, where no boundary reflections are present. However the MT responses fluctuate within a small range close to the values for the homogeneous Earth. The GPML formulation for MT and CSEM produce more accurate results and stabilize the MT responses over a frequency range. This algorithm is applied to synthetic examples with complex conductivity structures. Some of these synthetic examples have been published previously, thus the results of this algorithm are compared qualitatively. In the case of anisotropy and complex geometry, the proposed… Advisors/Committee Members: Zhou, Bing (advisor), Heinson, Graham Stewart (advisor), Thiel, Stephan (advisor), School of Earth and Environmental Sciences (school).

Subjects/Keywords: Vector Finite Elements; high-order elements; 3D magnetotelluric; hexahedral elements; forward modeling; anisotropy

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6^th Edition):

Rivera-Rios, A. M. (2014). Multi-order vector finite element modeling of 3D magnetotelluric data including complex geometry and anisotropy. (Thesis). University of Adelaide. Retrieved from http://hdl.handle.net/2440/85200

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16^th Edition):

Rivera-Rios, Aixa Maria. “Multi-order vector finite element modeling of 3D magnetotelluric data including complex geometry and anisotropy.” 2014. Thesis, University of Adelaide. Accessed December 11, 2019. http://hdl.handle.net/2440/85200.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7^th Edition):

Rivera-Rios, Aixa Maria. “Multi-order vector finite element modeling of 3D magnetotelluric data including complex geometry and anisotropy.” 2014. Web. 11 Dec 2019.

Vancouver:

Rivera-Rios AM. Multi-order vector finite element modeling of 3D magnetotelluric data including complex geometry and anisotropy. [Internet] [Thesis]. University of Adelaide; 2014. [cited 2019 Dec 11]. Available from: http://hdl.handle.net/2440/85200.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Rivera-Rios AM. Multi-order vector finite element modeling of 3D magnetotelluric data including complex geometry and anisotropy. [Thesis]. University of Adelaide; 2014. Available from: http://hdl.handle.net/2440/85200

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

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