The Experts below are selected from a list of 60795 Experts worldwide ranked by ideXlab platform
Jorg Ontrup - One of the best experts on this subject based on the ideXlab platform.
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the cyborg astrobiologist scouting red beds for uncommon features with Geological significance
arXiv: Computer Vision and Pattern Recognition, 2005Co-Authors: P C Mcguire, Enrique Diazmartinez, Jens Ormo, Javier Gomezelvira, Jose Antonio Rodriguezmanfredi, Eduardo Sebastianmartinez, Helge Ritter, Robert Haschke, Markus Oesker, Jorg OntrupAbstract:The `Cyborg Astrobiologist' (CA) has undergone a second Geological field trial, at a red sandstone site in northern Guadalajara, Spain, near Riba de Santiuste. The Cyborg Astrobiologist is a wearable computer and video camera system that has demonstrated a capability to find uncommon interest points in Geological imagery in real-time in the field. The first (of three) Geological Structures that we studied was an outcrop of nearly homogeneous sandstone, which exhibits oxidized-iron impurities in red and and an absence of these iron impurities in white. The white areas in these ``red beds'' have turned white because the iron has been removed by chemical reduction, perhaps by a biological agent. The computer vision system found in one instance several (iron-free) white spots to be uncommon and therefore interesting, as well as several small and dark nodules. The second Geological Structure contained white, textured mineral deposits on the surface of the sandstone, which were found by the CA to be interesting. The third Geological Structure was a 50 cm thick paleosol layer, with fossilized root Structures of some plants, which were found by the CA to be interesting. A quasi-blind comparison of the Cyborg Astrobiologist's interest points for these images with the interest points determined afterwards by a human geologist shows that the Cyborg Astrobiologist concurred with the human geologist 68% of the time (true positive rate), with a 32% false positive rate and a 32% false negative rate. (abstract has been abridged).
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the cyborg astrobiologist scouting red beds for uncommon features with Geological significance
International Journal of Astrobiology, 2005Co-Authors: P C Mcguire, Enrique Diazmartinez, Jens Ormo, Javier Gomezelvira, Jose Antonio Rodriguezmanfredi, Eduardo Sebastianmartinez, Helge Ritter, Robert Haschke, Markus Oesker, Jorg OntrupAbstract:The ‘Cyborg Astrobiologist’ has undergone a second Geological field trial, at a site in northern Guadalajara, Spain, near Riba de Santiuste. The site at Riba de Santiuste is dominated by layered deposits of red sandstones. The Cyborg Astrobiologist is a wearable computer and video camera system that has demonstrated a capability to find uncommon interest points in Geological imagery in real time in the field. In this second field trial, the computer vision system of the Cyborg Astrobiologist was tested at seven different tripod positions, on three different Geological Structures. The first Geological Structure was an outcrop of nearly homogeneous sandstone, which exhibits oxidized-iron impurities in red areas and an absence of these iron impurities in white areas. The white areas in these ‘red beds’ have turned white because the iron has been removed. The iron removal from the sandstone can proceed once the iron has been chemically reduced, perhaps by a biological agent. In one instance the computer vision system found several (iron-free) white spots to be uncommon and therefore interesting, as well as several small and dark nodules. The second Geological Structure was another outcrop some 600 m to the east, with white, textured mineral deposits on the surface of the sandstone, at the bottom of the outcrop. The computer vision system found these white, textured mineral deposits to be interesting. We acquired samples of the mineral deposits for geochemical analysis in the laboratory. This laboratory analysis of the crust identifies a double layer, consisting of an internal millimetre-size layering of calcite and an external centimetre-size efflorescence of gypsum. The third Geological Structure was a 50 cm thick palaeosol layer, with fossilized root Structures of some plants. The computer vision system also found certain areas of these root Structures to be interesting. A quasi-blind comparison of the Cyborg Astrobiologist's interest points for these images with the interest points determined afterwards by a human geologist shows that the Cyborg Astrobiologist concurred with the human geologist 68% of the time (true-positive rate), with a 32% false-positive rate and a 32% false-negative rate. The performance of the Cyborg Astrobiologist's computer vision system was by no means perfect, so there is plenty of room for improvement. However, these tests validate the image-segmentation and uncommon-mapping technique that we first employed at a different Geological site (Rivas Vaciamadrid) with somewhat different properties for the imagery.
Sarah A Derouin - One of the best experts on this subject based on the ideXlab platform.
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Geological Structure of the paradox valley region colorado and relationship to seismicity induced by deep well injection
Journal of Geophysical Research, 2014Co-Authors: Vanessa M King, Lisa V Block, William L Yeck, Christopher K Wood, Sarah A DerouinAbstract:The Bureau of Reclamation (Reclamation) operates a deep injection well at Paradox Valley in western Colorado. Seismicity has been recorded since 1985, with more than 5900 likely induced earthquakes detected since injection operations began in 1991, making this project a unique and valuable case study in the long-term development of injection-induced seismicity. Likely induced earthquakes occur in a complex pattern with clusters separated by aseismic gaps of 2 km or more, and have been observed up to 16 km from the injection well. To evaluate how the subsurface geologic Structure may control the occurrence of induced seismicity, we compare the earthquake locations to a set of geologic models that Reclamation commissioned prior to drilling the injection well. Our analysis indicates that many aspects of the observed seismicity pattern can be attributed to the complex geologic Structure. The earthquake depths and locations are generally consistent with the structural trends of the primary injection target formation, within the uncertainty of the models, and some of the mapped basement faults appear to serve as boundaries in the earthquake locations, suggesting that they are barriers to flow. Additionally, the majority of events follow the predicted fluid flow pattern, which trends northwest–southeast and wraps around Paradox Valley. Some features of the seismicity pattern, such as the early onset of seismicity to the northwest of the injection well and the distinct clustering, are not explained by the current geologic models and may be related to unmapped geologic features or local variations in the stress field.
Haim Gvirtzman - One of the best experts on this subject based on the ideXlab platform.
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effects of karst and Geological Structure on groundwater flow the case of yarqon taninim aquifer israel
Journal of Hydrology, 2010Co-Authors: Elad Dafny, Avi Burg, Haim GvirtzmanAbstract:Summary This study demonstrates the significant influences of the Geological Structure (especially folding and lithology) and the karst system on groundwater flow regime. Folds divert groundwater flow from the general hydraulic gradient; marly layers sustain several perched sub-aquifers above the regional aquifer; and karstification increases the hydraulic conductivity by several orders of magnitude. These phenomena are quantitatively demonstrated within the Yarqon-Taninim (YT) basin, Israel, which is a complex groundwater system, combining several (extremely) opposite characteristics: humid and arid recharge zones, phreatic and confined parts, shallow and deep sub-aquifers, stratified and relatively-homogeneous sub-basins, saline and fresh water bodies, as well as stagnant and fast-flowing groundwater regions. We have introduced a 3D Geological-based grid for the basin (for the first time). It was implemented into a numerical code (FEFLOW), which was used thereafter to analyze quantitatively the flow regime, the groundwater mass balance, and the aquifer hydraulic properties. We present up to date conceptual understanding and numerical modeling of the YT flow field, especially at its mountainous parts. Based on the calibration procedure and the sensitivity analyses, we obtained the best-fitted hydraulic conductivity values for the aquifer mesh. The general phenomenon observed is that as groundwater flow quantity increases, the hydraulic conductivity also increases. We interpret this result by the karstification mechanism (including paleo-karst). Thus, where groundwater flow-lines converge and where groundwater discharge amount increases, the karstification process intensifies and permeability increases. Consequently, at the mountainous region, along the syncline axes, where groundwater flow-lines converge, higher conductivities are found. Modeling results also exhibit that at the lowland confined area, the Geological Structure does not play a major role in directing groundwater flow. Rather, the flow field is controlled by the well-developed karst system and the relatively homogenous carbonate section. It is hypothesizes that the extensive karstification took place at the Messinian Salinity Crises, ∼5.5 Ma, during which groundwater heads as well as sea level were lowered by several 100 m.
P C Mcguire - One of the best experts on this subject based on the ideXlab platform.
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the cyborg astrobiologist scouting red beds for uncommon features with Geological significance
arXiv: Computer Vision and Pattern Recognition, 2005Co-Authors: P C Mcguire, Enrique Diazmartinez, Jens Ormo, Javier Gomezelvira, Jose Antonio Rodriguezmanfredi, Eduardo Sebastianmartinez, Helge Ritter, Robert Haschke, Markus Oesker, Jorg OntrupAbstract:The `Cyborg Astrobiologist' (CA) has undergone a second Geological field trial, at a red sandstone site in northern Guadalajara, Spain, near Riba de Santiuste. The Cyborg Astrobiologist is a wearable computer and video camera system that has demonstrated a capability to find uncommon interest points in Geological imagery in real-time in the field. The first (of three) Geological Structures that we studied was an outcrop of nearly homogeneous sandstone, which exhibits oxidized-iron impurities in red and and an absence of these iron impurities in white. The white areas in these ``red beds'' have turned white because the iron has been removed by chemical reduction, perhaps by a biological agent. The computer vision system found in one instance several (iron-free) white spots to be uncommon and therefore interesting, as well as several small and dark nodules. The second Geological Structure contained white, textured mineral deposits on the surface of the sandstone, which were found by the CA to be interesting. The third Geological Structure was a 50 cm thick paleosol layer, with fossilized root Structures of some plants, which were found by the CA to be interesting. A quasi-blind comparison of the Cyborg Astrobiologist's interest points for these images with the interest points determined afterwards by a human geologist shows that the Cyborg Astrobiologist concurred with the human geologist 68% of the time (true positive rate), with a 32% false positive rate and a 32% false negative rate. (abstract has been abridged).
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the cyborg astrobiologist scouting red beds for uncommon features with Geological significance
International Journal of Astrobiology, 2005Co-Authors: P C Mcguire, Enrique Diazmartinez, Jens Ormo, Javier Gomezelvira, Jose Antonio Rodriguezmanfredi, Eduardo Sebastianmartinez, Helge Ritter, Robert Haschke, Markus Oesker, Jorg OntrupAbstract:The ‘Cyborg Astrobiologist’ has undergone a second Geological field trial, at a site in northern Guadalajara, Spain, near Riba de Santiuste. The site at Riba de Santiuste is dominated by layered deposits of red sandstones. The Cyborg Astrobiologist is a wearable computer and video camera system that has demonstrated a capability to find uncommon interest points in Geological imagery in real time in the field. In this second field trial, the computer vision system of the Cyborg Astrobiologist was tested at seven different tripod positions, on three different Geological Structures. The first Geological Structure was an outcrop of nearly homogeneous sandstone, which exhibits oxidized-iron impurities in red areas and an absence of these iron impurities in white areas. The white areas in these ‘red beds’ have turned white because the iron has been removed. The iron removal from the sandstone can proceed once the iron has been chemically reduced, perhaps by a biological agent. In one instance the computer vision system found several (iron-free) white spots to be uncommon and therefore interesting, as well as several small and dark nodules. The second Geological Structure was another outcrop some 600 m to the east, with white, textured mineral deposits on the surface of the sandstone, at the bottom of the outcrop. The computer vision system found these white, textured mineral deposits to be interesting. We acquired samples of the mineral deposits for geochemical analysis in the laboratory. This laboratory analysis of the crust identifies a double layer, consisting of an internal millimetre-size layering of calcite and an external centimetre-size efflorescence of gypsum. The third Geological Structure was a 50 cm thick palaeosol layer, with fossilized root Structures of some plants. The computer vision system also found certain areas of these root Structures to be interesting. A quasi-blind comparison of the Cyborg Astrobiologist's interest points for these images with the interest points determined afterwards by a human geologist shows that the Cyborg Astrobiologist concurred with the human geologist 68% of the time (true-positive rate), with a 32% false-positive rate and a 32% false-negative rate. The performance of the Cyborg Astrobiologist's computer vision system was by no means perfect, so there is plenty of room for improvement. However, these tests validate the image-segmentation and uncommon-mapping technique that we first employed at a different Geological site (Rivas Vaciamadrid) with somewhat different properties for the imagery.
Vanessa M King - One of the best experts on this subject based on the ideXlab platform.
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Geological Structure of the paradox valley region colorado and relationship to seismicity induced by deep well injection
Journal of Geophysical Research, 2014Co-Authors: Vanessa M King, Lisa V Block, William L Yeck, Christopher K Wood, Sarah A DerouinAbstract:The Bureau of Reclamation (Reclamation) operates a deep injection well at Paradox Valley in western Colorado. Seismicity has been recorded since 1985, with more than 5900 likely induced earthquakes detected since injection operations began in 1991, making this project a unique and valuable case study in the long-term development of injection-induced seismicity. Likely induced earthquakes occur in a complex pattern with clusters separated by aseismic gaps of 2 km or more, and have been observed up to 16 km from the injection well. To evaluate how the subsurface geologic Structure may control the occurrence of induced seismicity, we compare the earthquake locations to a set of geologic models that Reclamation commissioned prior to drilling the injection well. Our analysis indicates that many aspects of the observed seismicity pattern can be attributed to the complex geologic Structure. The earthquake depths and locations are generally consistent with the structural trends of the primary injection target formation, within the uncertainty of the models, and some of the mapped basement faults appear to serve as boundaries in the earthquake locations, suggesting that they are barriers to flow. Additionally, the majority of events follow the predicted fluid flow pattern, which trends northwest–southeast and wraps around Paradox Valley. Some features of the seismicity pattern, such as the early onset of seismicity to the northwest of the injection well and the distinct clustering, are not explained by the current geologic models and may be related to unmapped geologic features or local variations in the stress field.