Applying reflection tomography in the postmigration domain to multifold ground-penetrating radar data

Bradford, John H.

doi:10.1190/1.2159051

Cited by 50 publications

(37 citation statements)

References 28 publications

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“…Most major equipment manufacturers now offer multi-channel systems that can be used for a range of purposes including the collection of continuous multi-offset surveys (Bradford, 2006) and data collection using multiple antenna frequencies and/or antenna polarizations (Streich et al, 2006) simultaneously ( Fig. 1B, C).…”

Section: Ground-penetrating Radarmentioning

confidence: 99%

Landform characterization using geophysics—Recent advances, applications, and emerging tools

Dam

2012

Geomorphology

108

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Section: Ground-penetrating Radarmentioning

confidence: 99%

Landform characterization using geophysics—Recent advances, applications, and emerging tools

Dam

2012

Geomorphology

108

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“…Common mid-point surveys are also used to estimate velocity and dielectric permittivity of the underground layers. These parameters can be obtained by imaging the same survey profile with different antenna separation; consequently, these GPR data can be processed using the same method that is applied for seismic reflection (Fisher et al, 1992;Davis et al, 1994;Bradford, 2006).…”

Section: Introductionmentioning

confidence: 99%

Estimating Dielectric Permittivity and Electric Conductivity From Simulated Multichannel GPR Pulses Using Aco and Quasi-Newton Inversion Techniques

Gomes¹,

Souto²,

Athayde³

et al. 2014

Rev. Bras. Geof.

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ABSTRACT. Inversion of synthetic ground-penetrating radar data to estimate both dielectric permittivity (ε) and electric conductivity (σ) properties simultaneously is presented in this paper. The synthetic Ground-Penetrating Radar (GPR) data was generated by the propagation of a one-dimensional electromagnetic wave (1-D EM wave) through a given geological model. The simulated EM trace was modeled by Finite Difference Time Domain method (FDTD) for three different frequencies (f ): 800, 1000 and 1200 MHz. Random noise was also introduced to evaluate inversion algorithm performance. The inversion of GPR data was performed by Ant Colony Optimization (ACO) and Quasi-Newton (QN) techniques. A modified ACO technique was applied to approximate conductivity for deepest positions, and to increase the accuracy and convergence along lower positions. The inversion techniques were able to estimate simultaneously the dielectric permittivity and electric conductivity from synthetic multi-frequency GPR data. The estimated electrical parameters can be used to derive a set of physical properties and to develop a better understanding of the underground geological or geotechnical media.Keywords: ground-penetrating radar, inversion of GPR data, Ant Colony Optimization, Quasi-Newton technique. RESUMO.Neste artigo apresenta-se o registro das ondas eletromagnéticas refletidas (dados sintéticos) e o uso deste registro em algoritmos de inversão que procuram estimar simultaneamente as propriedades permissividade elétrica (ε) e condutividade elétrica (σ). Os dados GPR sintéticos foram gerados pela propagação da onda unidimensional através de um determinado modelo geológico. O traço da onda eletromagnética (OEM) simulado foi modelado pelo método das diferenças finitas no domínio do tempo (FDTD) para três diferentes frequências (f ): 800, 1000 e 1200 MHz. Os ruídos randômicos foram introduzidos para verificar a performance do algoritmo de inversão. Os dados de inversão GPR (permissividade dielétrica e condutividade elétrica) foram obtidos pelos métodos Ant Colony Optimization (Otimização da Colônia de Formigas) (ACO) e Quasi-Newton (QN). O método ACO modificado foi aplicado para aproximar a condutividade em posições mais profundas e aumentar a precisão e a convergência ao longo da profundidade. Os métodos de inversão foram capazes de estimar simultaneamente duas propriedades do modelo geológico: a permissividade elétrica e a condutividade elétrica para levantamentos georradar multicanais. Os parâmetros elétricos estimados podem ser usados para derivar um conjunto de propriedades físicas e melhorar a compreensão dos meios geológico-geotécnicos em subsolo.Palavras-chave: radar de penetração no solo, inversão de dados GPR, Otimização da Colônia de Formigas, método Quasi-Newton.

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“…The data were corrected for normal moveout (NMO), stacked, and frequency-wavenumber (f-k) migrated at 0.092 m ns −1 (Figure 5b). Bradford (2006) demonstrates that prestackdepth migration (PSDM) and reflection tomography of multifold GPR radar data can significantly improve the signal-to-noise and provide more accurate velocity models than traditional GPR velocity estimation techniques. Using SeisSpace seismic data processing software, we performed Kirchhoff PSDM with an initial velocity of 0.092 mns −1 , followed by 2D reflection tomography in the postmigration domain to invert for a velocity model that minimized residual moveout of selected horizons (Figure 5c).…”

Section: Gpr Acquisition and Processingmentioning

confidence: 99%

Estimation of porosity and water saturation in dual-porosity pyroclastic deposits from joint analysis of compression, shear, and electromagnetic velocities

2018

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In situ measurements of porosity and water saturation of pyroclastic deposits have the potential to improve interpretations of geology and hydrology in volcanic regions, and to provide more accurate estimates of dense rock equivalent for volcanic eruptions. However, rock-property models must consider the dual-porosity structure of pyroclastic deposits (i.e., vesicles within pumices and intergranular pores). Vesicularity, intergranular porosity, and water saturation all affect the density, elasticity, and dielectric properties of pyroclastic materials, which control seismic and electromagnetic velocities. The data from active seismic and ground-penetrating radar (GPR) techniques may improve porosity and water saturation estimation if the responses of seismic and electromagnetic velocities to porosity and water saturation variations are complementary in pyroclastic deposits. We developed a dual-porosity petrophysical model to calculate seismic and electromagnetic velocities of pyroclastic deposits with known intergranular porosity, vesicularity, and water saturation, and we tested our ability to estimate porosity and water saturation from field measurements of seismic and electromagnetic velocities in pyroclastic deposits at Mount St. Helens, Washington, USA. Our petrophysical model demonstrates that seismic velocities are more sensitive to intergranular porosity and less sensitive to vesicularity; electromagnetic velocity is primarily controlled by volumetric water content. In a multioffset GPR and active seismic case study, seismic first-arrival traveltime tomography and multichannel analysis of surface waves can resolve high-velocity anomalies caused by porosity reduction. Joint petrophysical inversion of electromagnetic and seismic velocities indicates that although intergranular porosity and water saturation are well-constrained (i.e., standard deviations of approximately 0.05), quantitative estimates of vesicularity remain less certain (i.e., standard deviation of approximately 0.21), due to weak sensitivity.

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Applying reflection tomography in the postmigration domain to multifold ground-penetrating radar data

Cited by 50 publications

References 28 publications

Landform characterization using geophysics—Recent advances, applications, and emerging tools

Landform characterization using geophysics—Recent advances, applications, and emerging tools

Estimating Dielectric Permittivity and Electric Conductivity From Simulated Multichannel GPR Pulses Using Aco and Quasi-Newton Inversion Techniques

Estimation of porosity and water saturation in dual-porosity pyroclastic deposits from joint analysis of compression, shear, and electromagnetic velocities

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