Survey design to maximize the volume of exploration of the InfiniTEM system when looking for discrete targets

Desmarais, Jacques K.; Smith, Richard S.

doi:10.1016/j.jappgeo.2015.02.012

Cited by 6 publications

(10 citation statements)

References 15 publications

(30 reference statements)

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“…The primary field of the InfiniTEM system is computed using the method of Desmarais and Smith (2015a), who apply the sphere model of Smith and Lee (2001) to the InfiniTEM system. The primary field from the 800-× 800-m InfiniTEM loops was approximated as the field of 4624 infinitesimal magnetic dipoles.…”

Section: Methodsmentioning

confidence: 99%

“…As discussed in Desmarais and Smith (2015a) and Smith and Lee (2001), using the sphere model to approximate the response of a platelike conductor will generate the correct response shape and relative amplitude. However, the absolute response amplitude of the sphere may not equate to the absolute response amplitude of the equivalent plate model.…”

Section: Methodsmentioning

confidence: 99%

“…Because equation 4 allows one to preserve these properties, a sphere may be considered as an ideal approximation to a plate for our purposes. Examples comparing the sphere model with that of an analogous plate model may be found in Desmarais and Smith (2015a) or Smith and Lee (2001).…”

Section: Methodsmentioning

confidence: 99%

“…Consequently, Figures 6 and 7 depend on the position of the conductor along and transverse to the traverse line and the geometry of the transmitter loops. Because the simulated target is located between the loops and the fields between the loops are mostly uniform and horizontal (Desmarais and Smith, 2015a), Figures 6 and 7 can be used to obtain good results when investigating targets located in-between the loops and striking perpendicular to the traverse line when using a similar loop geometry. For better results, or when applied to a target with different strike and locations as well as different transmitter loop geometries, the approach outlined above can be used to determine depth and dip, by generating similar plots associated with the pertinent survey parameters.…”

Section: Desmarais and Smithmentioning

confidence: 99%

“…The two transmitter loops have reverse polarity and are connected in series in a figureeight-shaped loop design (Bérubé et al, 2006;Malo-Lalande, 2007;Brakni, 2011). The InfiniTEM system is beneficial because it generates a strong horizontal primary field between the two loops, which is useful for exploration in Archean terranes in which vertical conductors are abundant (Desmarais and Smith, 2015a). For the case of ground TDEM systems, the EE is analogous to the absolute value of the analytic signal.…”

Section: Introductionmentioning

confidence: 99%

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Combining spatial components and Hilbert transforms to interpret ground-time-domain electromagnetic data

Desmarais

Smith

2015

GEOPHYSICS

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We have developed a method for displaying or imaging data from a ground-time-domain electromagnetic system and for extracting the geometric parameters of a small conductor. The parameters are determined directly from the data using combinations of the spatial components of the secondary fields and their Hilbert transforms. The position of the target coincides with the peaks of the energy envelope (EE) or the T-component of the response. Here, the EE is the square root of the sum of the squares of the three spatial components and their Hilbert transforms, whereas the T-component response is an analogous quantity that excludes the Hilbert transform terms. Studies on synthetic models indicate that the T-component response is sharper than the EE in most possible target orientations. Once the position of a body has been determined using the peak of the T-component response, the dip of the target can be quantified using the ratio of the full-width at half-magnitude (FWHM) of the T-component response and the T-component Hilbert transform response, which is analogous to the EE but excludes the untransformed quantities. Finally, once all other geometric parameters have been determined, the depth of the target can be evaluated using the FWHM of the T-component response.The proposed modeling method was tested over an anomaly acquired at the Coulon field site during an InfiniTEM survey in the Abitibi greenstone belt of Quebec. The extracted geometric parameters were consistent with the available geologic information.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%