Resistivity and ground-penetrating radar images of fractures in a crystalline aquifer: a case study in Caiçara farm—NE Brazil

Silva, Carlos César Nascimento da; Medeiros, Walter E.; Sá, Emanuel Ferraz Jardim de; Neto, Pedro Xavier

doi:10.1016/j.jappgeo.2004.08.001

Cited by 28 publications

(5 citation statements)

References 8 publications

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“…tering: 700-1400 MHz) (Butnor et al, 2003;Dahboosh Al-Shiejiri, 2013). The Stolt F-K migration routine was used to correct for object position and collapsed hyperbolic reflections (diffracted waves) based on signal geometry (migration velocity: 12.8 cm ns −1 ) (Doolittle and Butnor, 2009). The waveform parameter of the time interval between zero crossings (ns) of the maximum reflected wave was extracted at the points of root detection in the radar profiles and calculated using RadExplorer v1.42 software.…”

Section: Alongmentioning

confidence: 99%

“…These conditions appear to promote the establishment and anchorage of trees under otherwise highly limiting soil water conditions. Several studies have reported that trees can get established in rock fractures (mainly calcic and permeable bedrock) (Estrada-Medina et al, 2010;Poot and Lambers, 2008) and that they locate their roots inside of this permeable material to exploit stored water (Schwinning, 2013;Querejeta et al, 2007). The combination of tomogram and radargram images (Fig.…”

Section: Dynamics Of Water Inside Of Weathered Bedrock and Spatial DImentioning

confidence: 99%

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Technical note: Application of geophysical tools for tree root studies in forest ecosystems in complex soils

et al. 2017

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Abstract. While semiarid forests frequently colonize rocky substrates, knowledge is scarce on how roots garner resources in these extreme habitats. The Sierra San Miguelito Volcanic Complex in central Mexico exhibits shallow soils and impermeable rhyolitic-rock outcrops, which impede water movement and root placement beyond the soil matrix. However, rock fractures, exfoliated rocks and soil pockets potentially permit downward water percolation and root growth. With ground-penetrating radar (GPR) and electrical resistivity tomography (ERT), two geophysical methods advocated by Jayawickreme et al. (2014) to advance root ecology, we advanced in the method development studying root and water distribution in shallow rocky soils and rock fractures in a semiarid forest. We calibrated geophysical images with in situ root measurements, and then extrapolated root distribution over larger areas. Using GPR shielded antennas, we identified both fine and coarse pine and oak roots from 0.6 to 7.5 cm diameter at different depths into either soil or rock fractures. We also detected, trees anchoring their trunks using coarse roots underneath rock outcroppings. With ERT, we tracked monthly changes in humidity at the soil–bedrock interface, which clearly explained spatial root distribution of both tree species. Geophysical methods have enormous potential in elucidating root ecology. More interdisciplinary research could advance our understanding in belowground ecological niche functions and their role in forest ecohydrology and productivity.

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Section: Alongmentioning

confidence: 99%

Section: Dynamics Of Water Inside Of Weathered Bedrock and Spatial DImentioning

confidence: 99%

Technical note: Application of geophysical tools for tree root studies in forest ecosystems in complex soils

et al. 2017

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“…The mechanical properties such as rock mass stability, heterogeneity, anisotropy, conductibility, permeability, connectivity, and displacement deformation are related to the distribution pattern, scale, and abundance of fracture zones and fractures [20,21]. Understanding spatial fracture distribution and space-filling patterns is a challenging task relevant to engineering applications such as underground construction, geothermal systems, petroleum reservoir exploration, unconventional shale gas production, groundwater management, CO 2 storage, radioactive waste disposal, and mining of mineral resources [22][23][24][25][26][27][28][29][30]. Therefore, knowledge and understanding of the properties of fracture systems greatly benefit the management of exploitation, design, and execution of new drill holes and the understanding of the petrophysical characteristics of rocks [7,31].…”

Section: Introductionmentioning

confidence: 99%

Fractal Characterization of Multiscale Fracture Network Distribution in Dolomites: Outcrop Analogue of Subsurface Reservoirs

Pavičić,

Duić,

Vrbaški

et al. 2023

Fractal Fract

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Fractured aquifers, especially dolomites, are important hydrocarbon reservoirs and sources of thermal and groundwater in many parts of the world, especially in the Alpine-Dinaric-Carpathian region. The most dominant porosity type is fracture porosity, which acts as the preferential fluid pathway in the subsurface, thus strongly controlling fluid flow. Outcrops provide valuable information for the characterization of fracture networks. Dolomite rock properties and structural and diagenetic processes result in fractured systems that can be considered fractals. The fracture network was analyzed on 14 vertical outcrops in 35 digitized photographs. The values of the fractal dimensions varied slightly by the software and method used, but the trends were consistent, which confirms that all methods are valid. Small values of fractal dimension indicate the dominance of a few small or large fractures, and high values of fractal dimension result from a combination of large numbers of small fractures accompanied by a few large fractures. The mean value of the fractal dimension for analyzed fracture networks was 1.648. The results indicate that the fracture network of the Upper Triassic dolomites can be approximated by fractal distribution and can be considered a natural fractal, and values can be extrapolated to higher and lower scales (1D and 3D).

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“…Francés et al (2014 integraram imagens de sensores remotos à geofísica (Ground Penetrating Radar, tomografia de resistividade elétrica e ressonância magnética) para definir forma e dimensão do meio fissural. Igualmente, Nascimento da Silva et al (2004) utilizaram métodos geofísicos rasos (eletrorresistividade e GPR) associados à neotectônica para analisar a diferença de produtividade entre poços situados a curtas distâncias entre si, uma vez que os esforços tectônicos atuais podem, em teoria, condicionar o atual comportamento "aberto" ou "fechado" das descontinuidades. Cassidy et al (2014) usaram técnicas multi-escala, envolvendo imagens Lidar e dados geofísicos magnéticos e eletromagnéticos, extrapolando as informações da escala de poço para a regional, enquanto Deyassa et al (2014) empregaram dados de produção de poços e perfis litológicos para analisar verticalmente a variação permoporosa do aquífero.…”

Section: Introductionunclassified

aquífero fissural no semiárido

et al. 2023

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Em grande área do NE do Brasil, em que se superpõem os efeitos do clima semiárido e terrenos cristalinos, aquíferos fissurais são as únicas fontes de água, principalmente nos períodos de seca prolongada. A locação de poços tradicional, baseada nas análises geológico-estrutural, geomorfológica e de produtos de sensores remotos envolve alto risco exploratório, resultando em cerca de 30 a 40 % de insucesso. Isso decorre da dificuldade de avaliação sobre quais são as descontinuidades dominantes (fratura ou foliação), bem como quais apresentam potencialidades hidrogeológicas mais elevadas. Nesta pesquisa foram integrados dados de levantamentos geofísicos aeroportados (eletromagnético e magnético) e terrestre (geoelétrico), além da análise estrutural com viés neotectônico. Com fins ao aprimoramento no trabalho de locação de poços, os resultados obtidos demonstram que os modelos riacho-fenda e calha elúvio-aluvionar comumente coexistem, permitindo esboçar as suas distribuições espaciais. Além disso, foi possível identificar aspectos geológicos e geofísicos importantes para discriminar em campo qual modelo ocorre de forma efetiva.

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Resistivity and ground-penetrating radar images of fractures in a crystalline aquifer: a case study in Caiçara farm—NE Brazil

Cited by 28 publications

References 8 publications

Technical note: Application of geophysical tools for tree root studies in forest ecosystems in complex soils

Technical note: Application of geophysical tools for tree root studies in forest ecosystems in complex soils

Fractal Characterization of Multiscale Fracture Network Distribution in Dolomites: Outcrop Analogue of Subsurface Reservoirs

aquífero fissural no semiárido

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