The Experts below are selected from a list of 5916 Experts worldwide ranked by ideXlab platform
Francisco Gutierrez - One of the best experts on this subject based on the ideXlab platform.
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the impact of groundwater drawdown and vacuum pressure on Sinkhole development physical laboratory models
Engineering Geology, 2020Co-Authors: Xianxuan Xiao, Francisco Gutierrez, Jesus GuerreroAbstract:Abstract A considerable proportion of the damaging Sinkholes worldwide correspond to human-induced subsidence events related to groundwater withdrawal and the associated water-table decline (e.g. aquifer overexploitation, dewatering for mining). Buoyancy loss in pre-existing cavity roofs is generally claimed to be the main underlying physical mechanism. It has been also postulated that rapid water-table drawdowns may create a vacuum effect in the subsurface and contribute to enhance Sinkhole activity in karstic terrains with a low effective porosity cover. Our laboratory physical model explores the role played by vacuum pressure induced water-table drops with different magnitudes and rates on Sinkhole development, simulating an invariable mantled karst comprising cavernous bedrock and a low-permeability cover. The multiple tests performed include real-time monitoring of the water level drawdown (magnitude, duration, rate), the negative air pressures in the bedrock cavity and the cover, and several features of the subsidence phenomena (deformation style, size, magnitude, rate). The main findings derived from the test results include: (1) Vacuum pressure may trigger the development of cover collapse Sinkholes in areas with low-permeability covers. (2) Different water-table decline patterns (magnitude, duration, rate) may result in different subsidence styles or rheological behaviours: sagging versus collapse. (3) Ground fissuring, frequently related to extension at the margin of sagging depressions, may cancel or significantly diminish the vacuum effect. (4) An overall direct relationship between the water-table decline rate and the subsidence rate. Some possible strategies are proposed to ameliorate the adverse effect of the negative air pressure on Sinkhole hazard, which most probably has a local impact restricted by the concurrence of rapid water drawdowns and low-permeability covers.
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4d monitoring of active Sinkholes with a terrestrial laser scanner tls a case study in the evaporite karst of the ebro valley ne spain
Remote Sensing, 2018Co-Authors: Alfonso Benitocalvo, Francisco Gutierrez, Jorge Sevil, G Desir, Domingo Carbonel, Jesus Guerrero, Ivan Fabregat, Adrian Martinezfernandez, Theodoros Karampaglidis, Angel GarciaarnayAbstract:This work explores, for the first time, the application of a Terrestrial Laser Scanner (TLS) and a comparison of point clouds in the 4D monitoring of active Sinkholes. The approach is tested in three highly-active Sinkholes related to the dissolution of salt-bearing evaporites overlain by unconsolidated alluvium. The Sinkholes are located in urbanized areas and have caused severe damage to critical infrastructure (flood-control dike, a major highway). The 3D displacement models derived from the comparison of point clouds with exceptionally high spatial resolution allow complex spatial and temporal subsidence patterns within one of the Sinkholes to be resolved. Detected changes in the subsidence activity (e.g., Sinkhole expansion, translation of the maximum subsidence zone, development of incipient secondary collapses) are related to potential controlling factors such as floods, water table changes or remedial measures. In contrast, with detailed mapping and high-precision leveling, the displacement models, covering a relatively short time span of around 6 months, do not capture the subtle subsidence (<0.6–1 cm) that affects the marginal zones of the Sinkholes, precluding precise mapping of the edges of the subsidence areas. However, the performance of TLS can be adversely affected by some methodological limitations and local conditions: (1) limited accuracy in large investigation areas that require the acquisition of a high number of scans, increasing the registration error; (2) surface changes unrelated to Sinkhole activity (e.g., vegetation, loose material); (3) traffic-related vibrations and wind blast that affect the stability of the scanner.
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identifying the boundaries of Sinkholes and subsidence areas via trenching and establishing setback distances
Engineering Geology, 2018Co-Authors: Francisco Gutierrez, Carles Roque, Mario Zarroca, Domingo Carbonel, Jesus Guerrero, Rogelio Linares, Xavier Comas, James P Mccalpin, A H CooperAbstract:Abstract One of the most effective mitigation strategies in Sinkhole areas is the exclusion of Sinkholes and their vicinity to construction. The application of this preventive measure requires precise mapping of the boundaries of the areas affected by subsidence and the establishment of adequate setback distances, which is an important policy issue with significant economic implications. Through the investigation of several buried Sinkholes in the mantled evaporite karst of the Ebro Valley by trenching, this work illustrates that the actual extent of the subsidence areas may be much larger than that inferred from surface mapping and geophysical surveys. The objective and accurate subsurface information acquired from trenches on the outer edge of the deformed ground revealed Sinkhole radii 2–3 times larger than initially estimated, increasing one order of magnitude the Sinkhole area. Trenches can therefore help to reduce mapping uncertainties and the size of setbacks. Moreover, the trenching technique, in combination with geochronological data and retrodeformation analyses, provides critical information on the subsidence phenomena and the characteristics of the Sinkholes relevant to hazard assessment. Since recommended setback distances found in the existing literature are highly variable and rather arbitrary, we include a discussion here on the main factors that should be considered when defining setback zones for Sinkholes.
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Sinkhole investigation in an urban area by trenching in combination with gpr ert and high precision leveling mantled evaporite karst of zaragoza city ne spain
Engineering Geology, 2017Co-Authors: Jorge Sevil, Francisco Gutierrez, Carles Roque, Mario Zarroca, G Desir, Domingo Carbonel, Jesus Guerrero, Rogelio Linares, Ivan FabregatAbstract:Abstract Sinkhole risks are becoming particularly severe in urban areas that lack careful planning and where karst depressions are frequently filled and developed. These built-up areas are the most challenging for Sinkhole investigation; they are the ones that require the highest priority and the application of novel approaches aimed at reducing the epistemic uncertainties associated with hazard assessments. This work illustrates the strengths of the rarely used trenching technique for the investigation of Sinkholes in mantled karst areas. The approach has been tested on a buried Sinkhole in the evaporite karst of Zaragoza city, analysing and comparing data gathered by trenching, Ground Penetrating Radar (GPR) using shielded and unshielded antennas with different frequencies, Electrical Resistivity Tomography (ERT) and high-precision leveling. The Sinkhole is located beneath a street and has led to the demolition of buildings, creating a risk situation that requires careful assessment and management. Trenching provided the largest amount of objective data required for hazard assessment: (1) Precise location of the Sinkhole edges. (2) Internal structure, cumulative displacement, subsidence mechanisms and their contribution. The trench exposed an asymmetric structure with a minimum vertical displacement of 6.2 m, comprising a complex collapse with different generations of faults and two marginal zones affected by gentle inward tilting. Collapse faulting accommodates at least 70% of the subsidence. (3) Age of the Sinkhole and average subsidence rate. The Sinkhole was initiated sometime before or within 337–435 cal yr AD, indicating a long-term subsidence rate of ca. 3.7–4.2 mm/yr. (4) Kinematic style, characterised by episodic collapse events, as supported by leveling data. The retrodeformation analysis, together with geochronological data, indicates four collapse events with a recurrence of around 400 years and suggests enhanced activity since ca. 1950 AD. The performance of GPR was highly variable, depending mainly on the type of antenna and the timing of data acquisition. The best-quality data were obtained with shielded antennas and during relatively drier conditions. The rather poor performance of ERT, commonly an adequate method for resolving subsidence structures at depth, is attributed to the complex structure of the collapse Sinkhole, with spatially-dense and abrupt resistivity changes in resistivity. This case study strongly substantiates the implementation of the relatively inexpensive and highly objective trenching technique in Sinkhole investigations.
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reconstructing the internal structure and long term evolution of hazardous Sinkholes combining trenching electrical resistivity imaging eri and ground penetrating radar gpr
Geomorphology, 2017Co-Authors: Ivan Fabregat, Francisco Gutierrez, Carles Roque, Mario Zarroca, Domingo Carbonel, Jesus Guerrero, Xavier Comas, Rogelio LinaresAbstract:Abstract The approaches aimed at characterising specific damaging Sinkholes have received limited attention compared with other ground instability phenomena (e.g. landslides). Moreover, the practicality of the trenching technique in combination with numerical dating and retro-deformation analysis for Sinkhole site-investigations has been barely explored. This work illustrates the advantages of combining geomorphic mapping, electrical resistivity imaging (ERI), ground penetrating radar (GPR) and trenching for Sinkhole characterisation and shows how the trenching technique contributes to fill significant gaps that neither geomorphic nor geophysical methods can address. Two large Sinkholes (> 200 m long) related to the interstratal karstification of evaporites and generated by contrasting subsidence mechanisms (sagging, collapse) were investigated in the Fluvia Valley, NE Spain. Although GPR data may provide high resolution information on subsidence-related stratigraphic and structural features at shallow depth, the profiles acquired in the investigated sites with 100 MHz shielded and 40 MHz unshielded antennae provided limited insight into the internal geometry of the Sinkholes due to reduced signal penetration related to the presence of conductive clayey material. The ERI sections satisfactorily imaged the general geometry of the sagging and collapse subsidence structures up to depths higher than 100 m and clearly captured the basal contact of the low-resistivity Sinkhole fill in the sections with adequate layout and resolution. The trenches, despite their limited depth (ca. 5 m) allowed us to obtain valuable objective information on several key aspects of the subsidence phenomenon: (1) mechanisms (deformation style) and kinematics (progressive versus episodic); (2) limits of ground deformation; (3) temporal evolution (expansion versus contraction); (4) chronology and timing of most recent deformation phase; (5) rates of subsidence and sedimentation; and (6) the role played by subsidence in the development of lacustrine environments and the associated sedimentation patterns.
Jorge Pedro Galve - One of the best experts on this subject based on the ideXlab platform.
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assessing Sinkhole activity in the ebro valley mantled evaporite karst using advanced dinsar
Geomorphology, 2015Co-Authors: Jorge Pedro Galve, Francisco Gutierrez, Carmen Castaneda, Gerardo HerreraAbstract:Abstract Sinkholes in karst areas may cause subsidence damage in transportation infrastructures, demolition of buildings and even the loss of human lives when they occur in a catastrophic way. Differential Interferometry (DInSAR) is a promising technology for detecting and characterizing Sinkholes, as well as for reducing the associated risk when combined with other sources of data such as a Sinkhole inventory. In this work, the usefulness of InSAR techniques and data for Sinkhole risk management has been analyzed through the comparison of three DInSAR-derived velocity maps with a comprehensive Sinkhole inventory in the Ebro Valley, NE Spain. The DInSAR maps have contributed to improve the Sinkhole inventory in different ways: (1) detection of non-inventoried Sinkholes; (2) revision of Sinkhole areas previously classified as inactive as active; and (3) refinement of underestimated Sinkhole boundaries. The obtained results suggest that DInSAR products are suitable for analyzing active dissolution-induced subsidence. The application of these techniques may help in recognizing and better characterizing previously unknown karst subsidence problems and in preventing personal and property losses. However, the analysis reveals that the available DInSAR maps combined overlook about 70% of the previously mapped active Sinkholes mainly due to decorrelation.
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application of risk cost benefit and acceptability analyses to identify the most appropriate geosynthetic solution to mitigate Sinkhole damage on roads
Engineering Geology, 2012Co-Authors: Jorge Pedro Galve, Francisco Gutierrez, Jesus Guerrero, Juan Carlos Alonso, Ignacio DiegoAbstract:Abstract Sinkholes in karst areas disrupt transportation route serviceability causing significant direct and indirect economic losses and may lead to accidents involving fatalities. A quantitative procedure has been developed to identify the most suitable mitigation designs for a road recently built in an area with a very high probability of Sinkhole occurrence. Installation of geogrids with different resistances to a variable number of road sections has been simulated taking into account the occurrence probability of Sinkholes with different diameters in each section. The proposed methodology includes the following phases: (1) Development of a Sinkhole hazard model that predicts the occurrence probability of Sinkholes with different diameters in each 5 × 5 m pixel of the road. (2) Vulnerability appraisal of the road by means of stability analyses. (3) Risk assessment for the “without geogrid” and multiple “with geogrid” scenarios including direct and indirect economic losses, as well as expected number of fatalities. (4) Cost–benefit analysis to estimate the net benefit of the mitigation designs. (5) Acceptability analysis considering geogrid solutions based on cost-effectiveness, conventional (maximum acceptable rate of fatalities) and utility-based (maximum acceptable investment in mitigation to prevent fatalities) criteria. (6) Sensitivity analysis to evaluate the impact of the uncertainty of a set of parameters on the most critical results from the risk management perspective. The presented method could be easily adapted to other geohazards (e.g. shallow landslides, rock-falls, piping), different infrastructures (e.g. railways), as well as to other corrective measures (e.g. concrete slabs, catch fences, armoured roofs, steel meshes, barrier systems).
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improving Sinkhole hazard models incorporating magnitude frequency relationships and nearest neighbor analysis
Geomorphology, 2011Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco GutierrezAbstract:Abstract This work presents a methodology for elaborating Sinkhole hazard models that incorporate the magnitude and frequency relationships of the subsidence process. The proposed approach has been tested in a sector of the Ebro valley mantled evaporite karst, where Sinkholes, largely induced by irrigation practices, have a very high occurrence rate (>50 Sinkholes/km 2 /yr). In this area, covering 10 km 2 , a total of 943 new cover collapse Sinkholes were inventoried in 2005 and 2006. Multiple susceptibility models have been generated analyzing the statistical relationships between the 2005 Sinkholes and different sets of variables, including the nearest Sinkhole distance . The quantitative evaluation of the prediction capability of these models using the 2006 Sinkhole population has allowed the identification of the method and variables that produce the most reliable predictions. The incorporation of the indirect variable nearest Sinkhole distance has contributed significantly to increase the quality of the models, despite simplifying the modeling process by using categorical rather than continuous variables. The best susceptibility model, generated with the total Sinkhole population and the selected method and variables, has been transformed into a hazard model that provides minimum estimates of the spatial–temporal probability of each pixel to be affected by Sinkholes of different diameter ranges. This transformation has been carried out combining two equations derived from the more complete 2006 Sinkhole population; one of them expressing the expected spatial–temporal probability of Sinkhole occurrence and the other the empirical magnitude and frequency relationships generated for two different types of land surfaces, which control the strength of the surface layer and the size of the Sinkholes. The presented method could be applied to predict the spatial–temporal probability of events with different magnitudes related to other geomorphic processes (e.g. landslides).
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evaluating and comparing methods of Sinkhole susceptibility mapping in the ebro valley evaporite karst ne spain
Geomorphology, 2009Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco Gutierrez, Pedro Lucha, J Bonachea, Antonio CendreroAbstract:Abstract Multiple Sinkhole susceptibility models have been generated in three study areas of the Ebro Valley evaporite karst (NE Spain) applying different methods (nearest neighbour distance, Sinkhole density, heuristic scoring system and probabilistic analysis) for each Sinkhole type separately (cover collapse Sinkholes, cover and bedrock collapse Sinkholes and cover and bedrock sagging Sinkholes). The quantitative and independent evaluation of the predictive capability of the models reveals that: (1) The most reliable susceptibility models are those derived from the nearest neighbour distance and Sinkhole density. These models can be generated in a simple and rapid way from detailed geomorphological maps. (2) The reliability of the nearest neighbour distance and density models is conditioned by the degree of clustering of the Sinkholes. Consequently, the karst areas in which Sinkholes show a higher clustering are a priori more favourable for predicting new occurrences. (3) The predictive capability of the best models obtained in this research is significantly higher (12.5–82.5%) than that of the heuristic Sinkhole susceptibility model incorporated into the General Urban Plan for the municipality of Zaragoza. Although the probabilistic approach provides lower quality results than the methods based on Sinkhole proximity and density, it helps to identify the most significant factors and select the most effective mitigation strategies and may be applied to model susceptibility in different future scenarios.
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Sinkholes in the salt bearing evaporite karst of the ebro river valley upstream of zaragoza city ne spain geomorphological mapping and analysis as a basis for risk management
Geomorphology, 2009Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco Gutierrez, Pedro Lucha, J Bonachea, Antonio Cendrero, M Gutierrez, M J Gimeno, Gonzalo Pardo, J A SanchezAbstract:Abstract A detailed Sinkhole map has been produced in a stretch of the Ebro Valley (40.8 km2) including the western sector of Zaragoza city (NE Spain). During the last few decades, around 70% of the original Sinkhole area has been filled with anthropogenic sediments causing the disappearance of 137 ha of wetlands. The interstratal karstification of salts (halite and glauberite) and a WNW–ESE-trending joint set have played a major control in the development of Sinkholes. Three morphometric types of Sinkholes have been differentiated, each attributed to a specific subsidence mechanism inferred from the paleoSinkholes exposed in the surrounding of Zaragoza city; sagging of bedrock and cover, collapse of bedrock and cover, and collapse of cover material related to the downward migration of particles through dissolutional conduits. Each type of Sinkhole is characterised by a distinctive behaviour in terms of controlling factors, spatio-temporal distribution and kinematics, and consequently the proposed differentiation may have a practical utility. The vast majority of the subsidence damage identified in the area occurs within the boundaries of pre-existing Sinkholes identifiable in old aerial photographs and topographical maps. This fact demonstrates that the application of preventive planning strategies based on detailed geomorphological maps would have allowed avoidance of most of the large financial losses caused by subsidence in the area, of the order of hundreds of thousands of euros per year.
Jesus Guerrero - One of the best experts on this subject based on the ideXlab platform.
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the impact of groundwater drawdown and vacuum pressure on Sinkhole development physical laboratory models
Engineering Geology, 2020Co-Authors: Xianxuan Xiao, Francisco Gutierrez, Jesus GuerreroAbstract:Abstract A considerable proportion of the damaging Sinkholes worldwide correspond to human-induced subsidence events related to groundwater withdrawal and the associated water-table decline (e.g. aquifer overexploitation, dewatering for mining). Buoyancy loss in pre-existing cavity roofs is generally claimed to be the main underlying physical mechanism. It has been also postulated that rapid water-table drawdowns may create a vacuum effect in the subsurface and contribute to enhance Sinkhole activity in karstic terrains with a low effective porosity cover. Our laboratory physical model explores the role played by vacuum pressure induced water-table drops with different magnitudes and rates on Sinkhole development, simulating an invariable mantled karst comprising cavernous bedrock and a low-permeability cover. The multiple tests performed include real-time monitoring of the water level drawdown (magnitude, duration, rate), the negative air pressures in the bedrock cavity and the cover, and several features of the subsidence phenomena (deformation style, size, magnitude, rate). The main findings derived from the test results include: (1) Vacuum pressure may trigger the development of cover collapse Sinkholes in areas with low-permeability covers. (2) Different water-table decline patterns (magnitude, duration, rate) may result in different subsidence styles or rheological behaviours: sagging versus collapse. (3) Ground fissuring, frequently related to extension at the margin of sagging depressions, may cancel or significantly diminish the vacuum effect. (4) An overall direct relationship between the water-table decline rate and the subsidence rate. Some possible strategies are proposed to ameliorate the adverse effect of the negative air pressure on Sinkhole hazard, which most probably has a local impact restricted by the concurrence of rapid water drawdowns and low-permeability covers.
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4d monitoring of active Sinkholes with a terrestrial laser scanner tls a case study in the evaporite karst of the ebro valley ne spain
Remote Sensing, 2018Co-Authors: Alfonso Benitocalvo, Francisco Gutierrez, Jorge Sevil, G Desir, Domingo Carbonel, Jesus Guerrero, Ivan Fabregat, Adrian Martinezfernandez, Theodoros Karampaglidis, Angel GarciaarnayAbstract:This work explores, for the first time, the application of a Terrestrial Laser Scanner (TLS) and a comparison of point clouds in the 4D monitoring of active Sinkholes. The approach is tested in three highly-active Sinkholes related to the dissolution of salt-bearing evaporites overlain by unconsolidated alluvium. The Sinkholes are located in urbanized areas and have caused severe damage to critical infrastructure (flood-control dike, a major highway). The 3D displacement models derived from the comparison of point clouds with exceptionally high spatial resolution allow complex spatial and temporal subsidence patterns within one of the Sinkholes to be resolved. Detected changes in the subsidence activity (e.g., Sinkhole expansion, translation of the maximum subsidence zone, development of incipient secondary collapses) are related to potential controlling factors such as floods, water table changes or remedial measures. In contrast, with detailed mapping and high-precision leveling, the displacement models, covering a relatively short time span of around 6 months, do not capture the subtle subsidence (<0.6–1 cm) that affects the marginal zones of the Sinkholes, precluding precise mapping of the edges of the subsidence areas. However, the performance of TLS can be adversely affected by some methodological limitations and local conditions: (1) limited accuracy in large investigation areas that require the acquisition of a high number of scans, increasing the registration error; (2) surface changes unrelated to Sinkhole activity (e.g., vegetation, loose material); (3) traffic-related vibrations and wind blast that affect the stability of the scanner.
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identifying the boundaries of Sinkholes and subsidence areas via trenching and establishing setback distances
Engineering Geology, 2018Co-Authors: Francisco Gutierrez, Carles Roque, Mario Zarroca, Domingo Carbonel, Jesus Guerrero, Rogelio Linares, Xavier Comas, James P Mccalpin, A H CooperAbstract:Abstract One of the most effective mitigation strategies in Sinkhole areas is the exclusion of Sinkholes and their vicinity to construction. The application of this preventive measure requires precise mapping of the boundaries of the areas affected by subsidence and the establishment of adequate setback distances, which is an important policy issue with significant economic implications. Through the investigation of several buried Sinkholes in the mantled evaporite karst of the Ebro Valley by trenching, this work illustrates that the actual extent of the subsidence areas may be much larger than that inferred from surface mapping and geophysical surveys. The objective and accurate subsurface information acquired from trenches on the outer edge of the deformed ground revealed Sinkhole radii 2–3 times larger than initially estimated, increasing one order of magnitude the Sinkhole area. Trenches can therefore help to reduce mapping uncertainties and the size of setbacks. Moreover, the trenching technique, in combination with geochronological data and retrodeformation analyses, provides critical information on the subsidence phenomena and the characteristics of the Sinkholes relevant to hazard assessment. Since recommended setback distances found in the existing literature are highly variable and rather arbitrary, we include a discussion here on the main factors that should be considered when defining setback zones for Sinkholes.
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Sinkhole investigation in an urban area by trenching in combination with gpr ert and high precision leveling mantled evaporite karst of zaragoza city ne spain
Engineering Geology, 2017Co-Authors: Jorge Sevil, Francisco Gutierrez, Carles Roque, Mario Zarroca, G Desir, Domingo Carbonel, Jesus Guerrero, Rogelio Linares, Ivan FabregatAbstract:Abstract Sinkhole risks are becoming particularly severe in urban areas that lack careful planning and where karst depressions are frequently filled and developed. These built-up areas are the most challenging for Sinkhole investigation; they are the ones that require the highest priority and the application of novel approaches aimed at reducing the epistemic uncertainties associated with hazard assessments. This work illustrates the strengths of the rarely used trenching technique for the investigation of Sinkholes in mantled karst areas. The approach has been tested on a buried Sinkhole in the evaporite karst of Zaragoza city, analysing and comparing data gathered by trenching, Ground Penetrating Radar (GPR) using shielded and unshielded antennas with different frequencies, Electrical Resistivity Tomography (ERT) and high-precision leveling. The Sinkhole is located beneath a street and has led to the demolition of buildings, creating a risk situation that requires careful assessment and management. Trenching provided the largest amount of objective data required for hazard assessment: (1) Precise location of the Sinkhole edges. (2) Internal structure, cumulative displacement, subsidence mechanisms and their contribution. The trench exposed an asymmetric structure with a minimum vertical displacement of 6.2 m, comprising a complex collapse with different generations of faults and two marginal zones affected by gentle inward tilting. Collapse faulting accommodates at least 70% of the subsidence. (3) Age of the Sinkhole and average subsidence rate. The Sinkhole was initiated sometime before or within 337–435 cal yr AD, indicating a long-term subsidence rate of ca. 3.7–4.2 mm/yr. (4) Kinematic style, characterised by episodic collapse events, as supported by leveling data. The retrodeformation analysis, together with geochronological data, indicates four collapse events with a recurrence of around 400 years and suggests enhanced activity since ca. 1950 AD. The performance of GPR was highly variable, depending mainly on the type of antenna and the timing of data acquisition. The best-quality data were obtained with shielded antennas and during relatively drier conditions. The rather poor performance of ERT, commonly an adequate method for resolving subsidence structures at depth, is attributed to the complex structure of the collapse Sinkhole, with spatially-dense and abrupt resistivity changes in resistivity. This case study strongly substantiates the implementation of the relatively inexpensive and highly objective trenching technique in Sinkhole investigations.
-
reconstructing the internal structure and long term evolution of hazardous Sinkholes combining trenching electrical resistivity imaging eri and ground penetrating radar gpr
Geomorphology, 2017Co-Authors: Ivan Fabregat, Francisco Gutierrez, Carles Roque, Mario Zarroca, Domingo Carbonel, Jesus Guerrero, Xavier Comas, Rogelio LinaresAbstract:Abstract The approaches aimed at characterising specific damaging Sinkholes have received limited attention compared with other ground instability phenomena (e.g. landslides). Moreover, the practicality of the trenching technique in combination with numerical dating and retro-deformation analysis for Sinkhole site-investigations has been barely explored. This work illustrates the advantages of combining geomorphic mapping, electrical resistivity imaging (ERI), ground penetrating radar (GPR) and trenching for Sinkhole characterisation and shows how the trenching technique contributes to fill significant gaps that neither geomorphic nor geophysical methods can address. Two large Sinkholes (> 200 m long) related to the interstratal karstification of evaporites and generated by contrasting subsidence mechanisms (sagging, collapse) were investigated in the Fluvia Valley, NE Spain. Although GPR data may provide high resolution information on subsidence-related stratigraphic and structural features at shallow depth, the profiles acquired in the investigated sites with 100 MHz shielded and 40 MHz unshielded antennae provided limited insight into the internal geometry of the Sinkholes due to reduced signal penetration related to the presence of conductive clayey material. The ERI sections satisfactorily imaged the general geometry of the sagging and collapse subsidence structures up to depths higher than 100 m and clearly captured the basal contact of the low-resistivity Sinkhole fill in the sections with adequate layout and resolution. The trenches, despite their limited depth (ca. 5 m) allowed us to obtain valuable objective information on several key aspects of the subsidence phenomenon: (1) mechanisms (deformation style) and kinematics (progressive versus episodic); (2) limits of ground deformation; (3) temporal evolution (expansion versus contraction); (4) chronology and timing of most recent deformation phase; (5) rates of subsidence and sedimentation; and (6) the role played by subsidence in the development of lacustrine environments and the associated sedimentation patterns.
Juan Remondo - One of the best experts on this subject based on the ideXlab platform.
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improving Sinkhole hazard models incorporating magnitude frequency relationships and nearest neighbor analysis
Geomorphology, 2011Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco GutierrezAbstract:Abstract This work presents a methodology for elaborating Sinkhole hazard models that incorporate the magnitude and frequency relationships of the subsidence process. The proposed approach has been tested in a sector of the Ebro valley mantled evaporite karst, where Sinkholes, largely induced by irrigation practices, have a very high occurrence rate (>50 Sinkholes/km 2 /yr). In this area, covering 10 km 2 , a total of 943 new cover collapse Sinkholes were inventoried in 2005 and 2006. Multiple susceptibility models have been generated analyzing the statistical relationships between the 2005 Sinkholes and different sets of variables, including the nearest Sinkhole distance . The quantitative evaluation of the prediction capability of these models using the 2006 Sinkhole population has allowed the identification of the method and variables that produce the most reliable predictions. The incorporation of the indirect variable nearest Sinkhole distance has contributed significantly to increase the quality of the models, despite simplifying the modeling process by using categorical rather than continuous variables. The best susceptibility model, generated with the total Sinkhole population and the selected method and variables, has been transformed into a hazard model that provides minimum estimates of the spatial–temporal probability of each pixel to be affected by Sinkholes of different diameter ranges. This transformation has been carried out combining two equations derived from the more complete 2006 Sinkhole population; one of them expressing the expected spatial–temporal probability of Sinkhole occurrence and the other the empirical magnitude and frequency relationships generated for two different types of land surfaces, which control the strength of the surface layer and the size of the Sinkholes. The presented method could be applied to predict the spatial–temporal probability of events with different magnitudes related to other geomorphic processes (e.g. landslides).
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improving Sinkhole hazard models incorporating magnitude frequency relationships and nearest neighbor analysis
Geomorphology, 2011Co-Authors: J P Galve, Juan Remondo, Francisco GutierrezAbstract:Abstract This work presents a methodology for elaborating Sinkhole hazard models that incorporate the magnitude and frequency relationships of the subsidence process. The proposed approach has been tested in a sector of the Ebro valley mantled evaporite karst, where Sinkholes, largely induced by irrigation practices, have a very high occurrence rate (>50 Sinkholes/km 2 /yr). In this area, covering 10 km 2 , a total of 943 new cover collapse Sinkholes were inventoried in 2005 and 2006. Multiple susceptibility models have been generated analyzing the statistical relationships between the 2005 Sinkholes and different sets of variables, including the nearest Sinkhole distance . The quantitative evaluation of the prediction capability of these models using the 2006 Sinkhole population has allowed the identification of the method and variables that produce the most reliable predictions. The incorporation of the indirect variable nearest Sinkhole distance has contributed significantly to increase the quality of the models, despite simplifying the modeling process by using categorical rather than continuous variables. The best susceptibility model, generated with the total Sinkhole population and the selected method and variables, has been transformed into a hazard model that provides minimum estimates of the spatial–temporal probability of each pixel to be affected by Sinkholes of different diameter ranges. This transformation has been carried out combining two equations derived from the more complete 2006 Sinkhole population; one of them expressing the expected spatial–temporal probability of Sinkhole occurrence and the other the empirical magnitude and frequency relationships generated for two different types of land surfaces, which control the strength of the surface layer and the size of the Sinkholes. The presented method could be applied to predict the spatial–temporal probability of events with different magnitudes related to other geomorphic processes (e.g. landslides).
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evaluating and comparing methods of Sinkhole susceptibility mapping in the ebro valley evaporite karst ne spain
Geomorphology, 2009Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco Gutierrez, Pedro Lucha, J Bonachea, Antonio CendreroAbstract:Abstract Multiple Sinkhole susceptibility models have been generated in three study areas of the Ebro Valley evaporite karst (NE Spain) applying different methods (nearest neighbour distance, Sinkhole density, heuristic scoring system and probabilistic analysis) for each Sinkhole type separately (cover collapse Sinkholes, cover and bedrock collapse Sinkholes and cover and bedrock sagging Sinkholes). The quantitative and independent evaluation of the predictive capability of the models reveals that: (1) The most reliable susceptibility models are those derived from the nearest neighbour distance and Sinkhole density. These models can be generated in a simple and rapid way from detailed geomorphological maps. (2) The reliability of the nearest neighbour distance and density models is conditioned by the degree of clustering of the Sinkholes. Consequently, the karst areas in which Sinkholes show a higher clustering are a priori more favourable for predicting new occurrences. (3) The predictive capability of the best models obtained in this research is significantly higher (12.5–82.5%) than that of the heuristic Sinkhole susceptibility model incorporated into the General Urban Plan for the municipality of Zaragoza. Although the probabilistic approach provides lower quality results than the methods based on Sinkhole proximity and density, it helps to identify the most significant factors and select the most effective mitigation strategies and may be applied to model susceptibility in different future scenarios.
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Sinkholes in the salt bearing evaporite karst of the ebro river valley upstream of zaragoza city ne spain geomorphological mapping and analysis as a basis for risk management
Geomorphology, 2009Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco Gutierrez, Pedro Lucha, J Bonachea, Antonio Cendrero, M Gutierrez, M J Gimeno, Gonzalo Pardo, J A SanchezAbstract:Abstract A detailed Sinkhole map has been produced in a stretch of the Ebro Valley (40.8 km2) including the western sector of Zaragoza city (NE Spain). During the last few decades, around 70% of the original Sinkhole area has been filled with anthropogenic sediments causing the disappearance of 137 ha of wetlands. The interstratal karstification of salts (halite and glauberite) and a WNW–ESE-trending joint set have played a major control in the development of Sinkholes. Three morphometric types of Sinkholes have been differentiated, each attributed to a specific subsidence mechanism inferred from the paleoSinkholes exposed in the surrounding of Zaragoza city; sagging of bedrock and cover, collapse of bedrock and cover, and collapse of cover material related to the downward migration of particles through dissolutional conduits. Each type of Sinkhole is characterised by a distinctive behaviour in terms of controlling factors, spatio-temporal distribution and kinematics, and consequently the proposed differentiation may have a practical utility. The vast majority of the subsidence damage identified in the area occurs within the boundaries of pre-existing Sinkholes identifiable in old aerial photographs and topographical maps. This fact demonstrates that the application of preventive planning strategies based on detailed geomorphological maps would have allowed avoidance of most of the large financial losses caused by subsidence in the area, of the order of hundreds of thousands of euros per year.
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probabilistic Sinkhole modelling for hazard assessment
Earth Surface Processes and Landforms, 2009Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco Gutierrez, Jesus Guerrero, Pedro Lucha, J Bonachea, Antonio CendreroAbstract:A method for quantitatively assessing Sinkhole susceptibility (spatial probability) and hazard (spatio-temporal probability) has been developed and independently tested in a 50 km2 sector of the Ebro Valley evaporite karst. Three genetic types of Sinkholes have been mapped in the floodplain and a terrace surface: 947 small cover-collapse Sinkholes (type 1, terrace), large collapse Sinkholes (type 2, floodplain) and large subsidence depressions (type 3, floodplain). The type 1 Sinkhole inventory includes two temporal populations: 447 Sinkholes formed before 24 November 2005, and 500 between that date and 2 November 2006. Sinkhole susceptibility models have been elaborated analysing the statistical relationships between the Sinkholes of the 2005 inventory and a set of potential conditioning factors. The independent evaluation (validation) of the susceptibility models by means of several strategies (random, sequentially excluded, and temporal) has allowed us to select the most significant variables for each Sinkhole type and assess quantitatively the quality of models; which are reasonable for the three Sinkhole types. Validation has also provided information on the contribution of specific variables and the effect of changing their accuracy to the prediction capability of models. Susceptibility models for type 3 Sinkholes have been validated satisfactorily with the 2006 Sinkhole inventory (temporal validation). The best susceptibility model has been transformed into a hazard map considering the frequency of Sinkholes that occurred in each susceptibility class between 2005 and 2006, as well as their average size. The susceptibility and hazard models obtained could be used as an objective basis for the application of mitigation measures, either of preventive or corrective nature. Copyright © 2008 John Wiley & Sons, Ltd.
Antonio Cendrero - One of the best experts on this subject based on the ideXlab platform.
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evaluating and comparing methods of Sinkhole susceptibility mapping in the ebro valley evaporite karst ne spain
Geomorphology, 2009Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco Gutierrez, Pedro Lucha, J Bonachea, Antonio CendreroAbstract:Abstract Multiple Sinkhole susceptibility models have been generated in three study areas of the Ebro Valley evaporite karst (NE Spain) applying different methods (nearest neighbour distance, Sinkhole density, heuristic scoring system and probabilistic analysis) for each Sinkhole type separately (cover collapse Sinkholes, cover and bedrock collapse Sinkholes and cover and bedrock sagging Sinkholes). The quantitative and independent evaluation of the predictive capability of the models reveals that: (1) The most reliable susceptibility models are those derived from the nearest neighbour distance and Sinkhole density. These models can be generated in a simple and rapid way from detailed geomorphological maps. (2) The reliability of the nearest neighbour distance and density models is conditioned by the degree of clustering of the Sinkholes. Consequently, the karst areas in which Sinkholes show a higher clustering are a priori more favourable for predicting new occurrences. (3) The predictive capability of the best models obtained in this research is significantly higher (12.5–82.5%) than that of the heuristic Sinkhole susceptibility model incorporated into the General Urban Plan for the municipality of Zaragoza. Although the probabilistic approach provides lower quality results than the methods based on Sinkhole proximity and density, it helps to identify the most significant factors and select the most effective mitigation strategies and may be applied to model susceptibility in different future scenarios.
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Sinkholes in the salt bearing evaporite karst of the ebro river valley upstream of zaragoza city ne spain geomorphological mapping and analysis as a basis for risk management
Geomorphology, 2009Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco Gutierrez, Pedro Lucha, J Bonachea, Antonio Cendrero, M Gutierrez, M J Gimeno, Gonzalo Pardo, J A SanchezAbstract:Abstract A detailed Sinkhole map has been produced in a stretch of the Ebro Valley (40.8 km2) including the western sector of Zaragoza city (NE Spain). During the last few decades, around 70% of the original Sinkhole area has been filled with anthropogenic sediments causing the disappearance of 137 ha of wetlands. The interstratal karstification of salts (halite and glauberite) and a WNW–ESE-trending joint set have played a major control in the development of Sinkholes. Three morphometric types of Sinkholes have been differentiated, each attributed to a specific subsidence mechanism inferred from the paleoSinkholes exposed in the surrounding of Zaragoza city; sagging of bedrock and cover, collapse of bedrock and cover, and collapse of cover material related to the downward migration of particles through dissolutional conduits. Each type of Sinkhole is characterised by a distinctive behaviour in terms of controlling factors, spatio-temporal distribution and kinematics, and consequently the proposed differentiation may have a practical utility. The vast majority of the subsidence damage identified in the area occurs within the boundaries of pre-existing Sinkholes identifiable in old aerial photographs and topographical maps. This fact demonstrates that the application of preventive planning strategies based on detailed geomorphological maps would have allowed avoidance of most of the large financial losses caused by subsidence in the area, of the order of hundreds of thousands of euros per year.
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probabilistic Sinkhole modelling for hazard assessment
Earth Surface Processes and Landforms, 2009Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco Gutierrez, Jesus Guerrero, Pedro Lucha, J Bonachea, Antonio CendreroAbstract:A method for quantitatively assessing Sinkhole susceptibility (spatial probability) and hazard (spatio-temporal probability) has been developed and independently tested in a 50 km2 sector of the Ebro Valley evaporite karst. Three genetic types of Sinkholes have been mapped in the floodplain and a terrace surface: 947 small cover-collapse Sinkholes (type 1, terrace), large collapse Sinkholes (type 2, floodplain) and large subsidence depressions (type 3, floodplain). The type 1 Sinkhole inventory includes two temporal populations: 447 Sinkholes formed before 24 November 2005, and 500 between that date and 2 November 2006. Sinkhole susceptibility models have been elaborated analysing the statistical relationships between the Sinkholes of the 2005 inventory and a set of potential conditioning factors. The independent evaluation (validation) of the susceptibility models by means of several strategies (random, sequentially excluded, and temporal) has allowed us to select the most significant variables for each Sinkhole type and assess quantitatively the quality of models; which are reasonable for the three Sinkhole types. Validation has also provided information on the contribution of specific variables and the effect of changing their accuracy to the prediction capability of models. Susceptibility models for type 3 Sinkholes have been validated satisfactorily with the 2006 Sinkhole inventory (temporal validation). The best susceptibility model has been transformed into a hazard map considering the frequency of Sinkholes that occurred in each susceptibility class between 2005 and 2006, as well as their average size. The susceptibility and hazard models obtained could be used as an objective basis for the application of mitigation measures, either of preventive or corrective nature. Copyright © 2008 John Wiley & Sons, Ltd.
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development and validation of Sinkhole susceptibility models in mantled karst settings a case study from the ebro valley evaporite karst ne spain
Engineering Geology, 2008Co-Authors: Jorge Pedro Galve, Juan Remondo, Francisco Gutierrez, Jesus Guerrero, Pedro Lucha, J Bonachea, Antonio Cendrero, M Gutierrez, J A SanchezAbstract:Abstract A preliminary Sinkhole susceptibility analysis has been carried out in a stretch 50 km 2 in area of the Ebro valley alluvial evaporite karst (NE Spain). A spatial database consisting of a Sinkhole layer and 27 thematic layers related to causal factors was constructed and implemented in a GIS. Three types of Sinkholes were differentiated on the basis of their markedly different morphometry and geomorphic distribution: large subsidence depressions (24), large collapse Sinkholes (23), and small cover-collapse Sinkholes (447). The susceptibility models were produced analysing the statistical relationships between the mapped Sinkholes and a set of conditioning factors using the Favourability Functions approach. The statistical analyses indicate that the best models are obtained with 6 conditioning factors out of the 27 available ones and that different factors and processes are involved in the generation of each type of Sinkhole. The validation of two models by means of a random-split strategy shows that reasonably good predictions on the spatial distribution of future dolines may be produced with this approach; around 75% of the Sinkholes of the validation sample occur on the 10% of the pixels with the highest susceptibility and about 45% of the area can be considered as safe.
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the origin typology spatial distribution and detrimental effects of the Sinkholes developed in the alluvial evaporite karst of the ebro river valley downstream of zaragoza city ne spain
Earth Surface Processes and Landforms, 2007Co-Authors: Francisco Gutierrez, Jorge Pedro Galve, Juan Remondo, Jesus Guerrero, Pedro Lucha, J Bonachea, Antonio Cendrero, M Gutierrez, J A SanchezAbstract:Three types of Sinkhole have been mapped in a 50 km2 stretch of the Ebro River valley downstream of Zaragoza: large collapse Sinkholes, large shallow subsidence depressions and small cover-collapse Sinkholes. The Sinkholes relate to the karstification of evaporitic bedrock that wedges out abruptly downstream, giving way to a shale substratum. Twenty-three collapse Sinkholes, up to 50 m in diameter by 6 m deep, and commonly hosting saline ponds, have been identified in the floodplain. They have been attributed to the upward stoping of dissolutional cavities formed within the evaporitic bedrock by rising groundwater flows. Twenty-four large shallow subsidence depressions were mapped in the floodplain. These may reach 850 m in length and were formed by structurally controlled interstratal karstification of soluble beds (halite or glauberite? and gypsum) by rising groundwater flow and the progressive settlement of the overlying bedrock and overburden sediments. A total of 447 small cover-collapse, or dropout, Sinkholes have been recognized in a perched alluvial level along the southern margin of the valley. These Sinkholes result from the upward propagation of voids through the alluvial mantle caused by the downward migration of detrital sediments into dissolutional voids. The majority of these Sinkholes, commonly 1·5–2 m in diameter, are induced by human activities. Over the karstic bedrock, there is a significant increase in Sinkhole density downstream. This is interpreted as being a result of the evaporitic bedrock wedging out and the convergence of the groundwater flow lines in the karstic aquifer. The collapse Sinkholes in this area, locally with a probability of occurrence higher than 140 Sinkholes/km2/year, cause substantial damage to the linear infrastructures, buildings and agriculture, and they might eventually cause the loss of human lives. Copyright © 2006 John Wiley & Sons, Ltd.
