Inversion of multiple intersecting high-resolution crosshole GPR profiles for hydrological characterization at the Boise Hydrogeophysical Research Site

Dafflon, Baptiste; Irving, James; Barrash, Warren

doi:10.1016/j.jappgeo.2011.02.001

Cited by 51 publications

(47 citation statements)

References 31 publications

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“…The FWI results clearly show the boundaries of the main units at 12 and 16 m, which have a good correspondence with the findings of previous studies [6,9,10,11,12]. The boundary around 6.5 m depth is less clear (likely the base of a sandy lens within Unit 4 that is continuous between wells C5 and C6, W. Barrash, pers.…”

Section: Comparison Of the Observed And Simulated Radar Tracessupporting

confidence: 89%

Full-waveform inversion of cross-hole GPR data measured at the boise gravel aquifer

Yang

Klotzsche

Kruk

et al. 2011

2011 6th International Workshop on Advanced Ground Penetrating Radar (IWAGPR)

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Cross-hole radar tomography is a useful tool for mapping shallow subsurface dielectric permittivity (ε) and electrical conductivity (σ) parameters. Conventional ray-based tomography suffers from some shortcomings: it provides relatively low resolution images and it cannot supply reliable information on certain types of low velocity structure. Higher resolution images can be provided by full-waveform inversion that uses significantly more information of the data. Since the first application of full-waveform inversion on experimental GPR data, the algorithm has been significantly improved. An overview is given of all developments by applying different versions of the full-waveform inversion to the experimental data set acquired at the Boise Hydrogeophysics Research Site in Idaho. Almost all improvements resulted in a reducing final misfit between the measured and synthetic data and a reducing gradient at the final iteration.

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Section: Comparison Of the Observed And Simulated Radar Tracessupporting

confidence: 89%

Full-waveform inversion of cross-hole GPR data measured at the boise gravel aquifer

Yang

Klotzsche

Kruk

et al. 2011

2011 6th International Workshop on Advanced Ground Penetrating Radar (IWAGPR)

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“…The geophysical responses caused by changes in relative dielectrical permittivity ε or electrical conductivity σ can be linked to the aquifer parameters of porosity, permeability, fluid content, and salinity (e.g., Hagrey and Müller, 2000;Garambois et al, 2002;Turesson, 2006). In this paper, we discuss the use of crosshole bistatic ground-penetrating radar (GPR) tomography to provide high-resolution images of the subsurface electromagnetic (EM) parameters, which can be closely related to the hydrogeologic parameters (e.g., Binley et al, 2001;Tronicke et al, 2004;Johnson et al, 2007;Bradford et al, 2009;Doetsch et al, 2010a;Dafflon et al, 2011). In conventional GPR tomography, first-arrival times and first-cycle amplitudes of the transmitted radar pulses are used in ray-based inversion schemes to visualize the interwell medium.…”

Section: Introductionmentioning

confidence: 99%

Crosshole GPR full-waveform inversion of waveguides acting as preferential flow paths within aquifer systems

et al. 2012

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High-contrast layers caused by porosity or clay content changes can have a dominant effect on hydraulic processes within an aquifer. These layers can act as low-velocity waveguides for GPR waves. We used a field example from a hydrological test site in Switzerland to show that fullwaveform inversion of crosshole GPR signals could image a subwavelength thickness low-velocity waveguiding layer. We exploited the full information content of the data, whereas ray-based inversion techniques are not able to image such thin waveguide layers because they only exploit the first-arrival times and first-cycle amplitudes. This lowvelocity waveguide layer is caused by an increase in porosity and indicates a preferential flow path within the aquifer. The waveguide trapping causes anomalously high amplitudes and elongated wavetrains to be observed for a transmitter within the waveguide and receivers straddling the waveguide depth range. The excellent fit of amplitudes and phase between the measured and modeled data confirms its presence. This new method enables detailed aquifer characterization to accurately predict transport and flow and can be applied to a wide range of geologic, hydrological, and engineering investigations.

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“…Note the closer correspondence in the lower portion of the stratigraphy in which K and porosity are more related in the Kozeny-Carman sense . sion of σ 0 measurements are broadly supportive of the multiscale heterogeneity affecting hydraulic, lithologic, and geophysical parameters, which has been demonstrated in the sedimentary structure of the site (Barrash and Clemo, 2002;Barrash and Reboulet, 2004), and recognition of two types of electrical-porosity (and dielectric-porosity) behavior evident in the subdivision of unit 2 into units 2A and 2B (Ernst et al, 2007;Irving et al, 2007;Mwenifumbo et al 2009;Dafflon et al, 2011b). Observation of ∅ and CR logs and analysis of correlation between ∅ and CR show strong correlation at the stratigraphic unit scale but highly variable weak to strong correlation at the subunit scale (Figure 14 here and Barrash and Cardiff, 2013).…”

Section: Units and Multiscale Structurementioning

confidence: 54%

“…Furthermore, crosshole GPR analysis was conducted by Ernst et al (2007) and Irving et al (2007). Dafflon et al (2011b) invert multiple intersecting high-resolution crosshole GPR profiles at the BHRS and obtain a 3D distribution of ∅ values that are in broad agreement with the results of the geostatistical study by Barrash and Clemo (2002).…”

Section: Hydrogeophysical Settingmentioning

confidence: 69%

The hydrogeologic information in cross-borehole complex conductivity data from an unconsolidated conglomeratic sedimentary aquifer

et al. 2016

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Accurate estimation of the hydrological properties of nearsurface aquifers is important because these properties strongly influence groundwater flow and solute transport. Laboratorybased investigations have indicated that induced polarization (IP) properties of porous media may be linked, through either semiempirical or fully mechanistic models, to hydrological properties including hydraulic conductivity. Therefore, there is a need for field assessments of the value of IP measurements in providing insights into the hydrological properties of aquifers. A cross-borehole IP survey was carried out at the Boise Hydrogeophysical Research Site (BHRS), an unconsolidated fluvial aquifer that has previously been well-studied with a variety of geophysical and hydrogeologic techniques. High-quality IP measurements were inverted, with careful consideration of the data error structure, to provide a 3D distribution of complex electrical conductivity values. The inverted distribution was further simplified using k-means cluster analysis to divide the inverted volume into discrete zones with horizontal layering. Identified layers based on complex electrical conductivity inversions are in broad agreement with stratigraphic units identified in previous studies at the site. Although mostly subtle variations in the phase angle are recovered through inversion of field data, greater contrasts in the IP data are evident at some unit boundaries. However, in coarse-grained aquifers, such as the BHRS, the discrimination of mildly contrasting lithologic units and associated changes in hydraulic conductivity of one or two orders of magnitude are unlikely to be achieved through field IP surveys. Despite the difficulty of differentiating subtle differences between all units, overall estimates of hydraulic conductivity purely from our field IP data are typically within an order of magnitude of independently measured values.

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Inversion of multiple intersecting high-resolution crosshole GPR profiles for hydrological characterization at the Boise Hydrogeophysical Research Site

Cited by 51 publications

References 31 publications

Full-waveform inversion of cross-hole GPR data measured at the boise gravel aquifer

Full-waveform inversion of cross-hole GPR data measured at the boise gravel aquifer

Crosshole GPR full-waveform inversion of waveguides acting as preferential flow paths within aquifer systems

The hydrogeologic information in cross-borehole complex conductivity data from an unconsolidated conglomeratic sedimentary aquifer

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