Quantitatively linking observations from independent non-invasive soil assessment methods enhances our ability to understand root zone processes. Electrical Resistivity Tomography (ERT) and X-ray Computed Tomography (CT) are two advanced non-invasive technologies routinely employed in soil science. ERT allows 4D process monitoring ( e.g., solute transport) and is sensitive to changes in moisture content (MC) and soil texture. X-ray CT is a higher resolution method used to appraise soil structure. We measured the variation of electrical resistivity and X-ray absorption with gravimetric moisture content (GMC) for two distinct soil types. Experimental results were compared with existing pedophysical relationships that express these dependencies. Based on the good fit between measurements and model predictions, we formulated a new pedophysical relationship that links directly the two soil properties. This will allow a direct translation between ERT and X-ray data for the study of root-zone parameters under well-defined experimental circumstances.
{"title":"A Pedophysical Relationship between X-ray Computed Tomography and Electrical Resistivity Data","authors":"M. Cimpoiaşu, O. Kuras, T. Pridmore, S. Mooney","doi":"10.2113/JEEG19-079","DOIUrl":"https://doi.org/10.2113/JEEG19-079","url":null,"abstract":"Quantitatively linking observations from independent non-invasive soil assessment methods enhances our ability to understand root zone processes. Electrical Resistivity Tomography (ERT) and X-ray Computed Tomography (CT) are two advanced non-invasive technologies routinely employed in soil science. ERT allows 4D process monitoring ( e.g., solute transport) and is sensitive to changes in moisture content (MC) and soil texture. X-ray CT is a higher resolution method used to appraise soil structure. We measured the variation of electrical resistivity and X-ray absorption with gravimetric moisture content (GMC) for two distinct soil types. Experimental results were compared with existing pedophysical relationships that express these dependencies. Based on the good fit between measurements and model predictions, we formulated a new pedophysical relationship that links directly the two soil properties. This will allow a direct translation between ERT and X-ray data for the study of root-zone parameters under well-defined experimental circumstances.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"29 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89156849","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yi-guo Xue, Zhang Kai, Maoxin Su, Xia Teng, Zhao Ying, Peng Wang
Residential districts dominated by limestone are likely to be impacted by undesirable groundwater seepage accidents. Such groundwater seepage can generally give rise to loss of life and property. To control groundwater seepage, increasingly accurate and reliable methods for surveying are becoming indispensable. We proposed a survey method to confirm groundwater sources and preferential flow paths in urban limestone-based residential districts via ground penetrating radar (GPR) and time domain electromagnetic method (TDEM). Firstly, we established the geophysical exploration plan after careful analysis of available hydrogeological survey data including terrain, stratum distribution and water table. Survey lines were designed parallel to existing urban roads and perpendicular to the ground. Next, we used GPR and TDEM to detect gravels in the permeable layer and water-rich regions in the aquifer. Drilling method was adopted for comparisons to resulting images. Finally, integrated interpretation indicated accurate measures of groundwater sources, main preferential flow paths and the preliminary classification of groundwater leakage risk in a study region. The feasibility and effectiveness of the GPR and TDEM survey method were verified in the hydrogeological survey at the Lingxiucheng Residential District in China, where a thick limestone layer existed and groundwater leakage accidents had occurred in basements of houses. The method had high reliability for limestone topographies and was improved to be an effective and low-cost solution to overcome physical limitations of existent buildings and traffic jams in urban areas. Therefore, our research can be extended to similar projects and related problems to help better map urban limestone-based residential districts and reduce groundwater seepage.
{"title":"A Survey Method on Groundwater Sources and Preferential Flow Paths In Urban Limestone-Based Residential Districts","authors":"Yi-guo Xue, Zhang Kai, Maoxin Su, Xia Teng, Zhao Ying, Peng Wang","doi":"10.2113/JEEG19-075","DOIUrl":"https://doi.org/10.2113/JEEG19-075","url":null,"abstract":"Residential districts dominated by limestone are likely to be impacted by undesirable groundwater seepage accidents. Such groundwater seepage can generally give rise to loss of life and property. To control groundwater seepage, increasingly accurate and reliable methods for surveying are becoming indispensable. We proposed a survey method to confirm groundwater sources and preferential flow paths in urban limestone-based residential districts via ground penetrating radar (GPR) and time domain electromagnetic method (TDEM). Firstly, we established the geophysical exploration plan after careful analysis of available hydrogeological survey data including terrain, stratum distribution and water table. Survey lines were designed parallel to existing urban roads and perpendicular to the ground. Next, we used GPR and TDEM to detect gravels in the permeable layer and water-rich regions in the aquifer. Drilling method was adopted for comparisons to resulting images. Finally, integrated interpretation indicated accurate measures of groundwater sources, main preferential flow paths and the preliminary classification of groundwater leakage risk in a study region. The feasibility and effectiveness of the GPR and TDEM survey method were verified in the hydrogeological survey at the Lingxiucheng Residential District in China, where a thick limestone layer existed and groundwater leakage accidents had occurred in basements of houses. The method had high reliability for limestone topographies and was improved to be an effective and low-cost solution to overcome physical limitations of existent buildings and traffic jams in urban areas. Therefore, our research can be extended to similar projects and related problems to help better map urban limestone-based residential districts and reduce groundwater seepage.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"39 1","pages":"235-244"},"PeriodicalIF":1.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79725200","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Articles","authors":"D. Rucker","doi":"10.2113/jeeg25.2.vi","DOIUrl":"https://doi.org/10.2113/jeeg25.2.vi","url":null,"abstract":"","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"111 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82422592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V. Olenchenko, P. Osipova, N. Yurkevich, S. Bortnikova
Ore mining and processing dumps are open and technogenic systems, which change intensively with time under the influence of environmental factors. Active transformations of such “technogenic deposits” are in close relationship with environmental factors. The purpose of this paper is to determine the nature and causes of the electrical resistivity (ER) changes in the mine tailings dump over time. The investigations were carried out by the method of electrotomography by determining the ER of the section to a depth of 1.5 m with an interval of one hour during the day with simultaneous recording of the substance temperature at a depth of 0.1 m. The maximum daily ER dynamics is observed over intensely transformed technogenic ores. ER is in a numerical relationship with the temperature of the solid matter by an exponential law with a certainty of 96%. A direct dependence of the ER daily changes amplitude on the cementation index m was revealed with the help of the Archie law. The primary material of the heap has a monodisperse composition and small values of m, so the amplitude of the ER dynamics is minimal. As a result of oxidative transformations, the solid matter of the dump becomes polydisperse, which is reflected in the cementation index and the amplitude of the ER daily oscillations increase.
{"title":"Electrical Resistivity Dynamics Beneath the Weathered Mine Tailings in Response to Ambient Temperature","authors":"V. Olenchenko, P. Osipova, N. Yurkevich, S. Bortnikova","doi":"10.2113/JEEG18-096","DOIUrl":"https://doi.org/10.2113/JEEG18-096","url":null,"abstract":"Ore mining and processing dumps are open and technogenic systems, which change intensively with time under the influence of environmental factors. Active transformations of such “technogenic deposits” are in close relationship with environmental factors. The purpose of this paper is to determine the nature and causes of the electrical resistivity (ER) changes in the mine tailings dump over time. The investigations were carried out by the method of electrotomography by determining the ER of the section to a depth of 1.5 m with an interval of one hour during the day with simultaneous recording of the substance temperature at a depth of 0.1 m. The maximum daily ER dynamics is observed over intensely transformed technogenic ores. ER is in a numerical relationship with the temperature of the solid matter by an exponential law with a certainty of 96%. A direct dependence of the ER daily changes amplitude on the cementation index m was revealed with the help of the Archie law. The primary material of the heap has a monodisperse composition and small values of m, so the amplitude of the ER dynamics is minimal. As a result of oxidative transformations, the solid matter of the dump becomes polydisperse, which is reflected in the cementation index and the amplitude of the ER daily oscillations increase.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"1 1","pages":"55-63"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89111563","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lin Zhou, J. Liao, Jingye Li, C. Xiaohong, Tianchun Yang, A. Hursthouse
Accurately inverting changes in the reservoir elastic parameters that are caused by oil and gas exploitation is of great importance in accurately describing reservoir dynamics and enhancing recovery. Previously numerous time-lapse seismic inversion methods based on the approximate formulas of exact Zoeppritz equations or wave equations have been used to estimate these changes. However the low accuracy of calculations using approximate formulas and the significant calculation effort for the wave equations seriously limits the field application of these methods. However, these limitations can be overcome by using exact Zoeppritz equations. Therefore, we study the time-lapse seismic difference inversion method using the exact Zoeppritz equations. Firstly, the forward equation of time-lapse seismic difference data is derived based on the exact Zoeppritz equations. Secondly, the objective function based on Bayesian inversion theory is constructed using this equation, with the changes in elastic parameters assumed to obey a Gaussian distribution. In order to capture the sharp time-lapse changes of elastic parameters and further enhance the resolution of the inversion results, the blockiness constraint, which follows the differentiable Laplace distribution, is added to the prior Gaussian background model. All examples of its application show that the proposed method can obtain stable and reasonable P- and S-wave velocities and density changes from the difference data. The accuracy of estimation is higher than for existing methods, which verifies the effectiveness and feasibility of the new method. It can provide high-quality seismic inversion results for dynamic detailed reservoir description and well location during development.
{"title":"Bayesian Time-lapse Difference Inversion Based on the exact Zoeppritz Equations with Blockiness Constraint","authors":"Lin Zhou, J. Liao, Jingye Li, C. Xiaohong, Tianchun Yang, A. Hursthouse","doi":"10.2113/JEEG19-045","DOIUrl":"https://doi.org/10.2113/JEEG19-045","url":null,"abstract":"Accurately inverting changes in the reservoir elastic parameters that are caused by oil and gas exploitation is of great importance in accurately describing reservoir dynamics and enhancing recovery. Previously numerous time-lapse seismic inversion methods based on the approximate formulas of exact Zoeppritz equations or wave equations have been used to estimate these changes. However the low accuracy of calculations using approximate formulas and the significant calculation effort for the wave equations seriously limits the field application of these methods. However, these limitations can be overcome by using exact Zoeppritz equations. Therefore, we study the time-lapse seismic difference inversion method using the exact Zoeppritz equations. Firstly, the forward equation of time-lapse seismic difference data is derived based on the exact Zoeppritz equations. Secondly, the objective function based on Bayesian inversion theory is constructed using this equation, with the changes in elastic parameters assumed to obey a Gaussian distribution. In order to capture the sharp time-lapse changes of elastic parameters and further enhance the resolution of the inversion results, the blockiness constraint, which follows the differentiable Laplace distribution, is added to the prior Gaussian background model. All examples of its application show that the proposed method can obtain stable and reasonable P- and S-wave velocities and density changes from the difference data. The accuracy of estimation is higher than for existing methods, which verifies the effectiveness and feasibility of the new method. It can provide high-quality seismic inversion results for dynamic detailed reservoir description and well location during development.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"1 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89304010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ground penetrating radar (GPR) is considered an effective tool to detect tunnel lining voids. In this paper, an experimental study was carried out using a physical tunnel lining model to evaluate the performances of different antenna frequencies. We built a 4.2 m–long, 4.2 m–wide, and 2.0 m–high experimental model to simulate the secondary lining, initial lining, and surrounding rock of a tunnel structure. In the model, we created four categories of voids, which are voids in secondary and initial linings, a delamination between the secondary and initial linings, a delamination between the initial lining and sand, and a void buried in the sand, to simulate real cases in tunnel engineering. The GPR wave velocities in the sand and concrete of the model were measured using the reflection method for the calibration of void depth. We employed a commercial GPR system equipped with antennae of different centre frequencies to detect the voids. GPR data were processed using a conventional data processing flow, and the performances of different frequencies were examined. The results show that the 1000 MHz centre frequency GPR is capable of characterizing shallow buried voids in the secondary lining but is not able to penetrate into the initial lining. The 250 MHz centre frequency GPR system is not advised to detect voids in or behind tunnel linings due to its low resolving power for voids of centimetre sizes. The 500 MHz centre frequency GPR system is optimal for void detection because it demonstrated a balanced performance of resolving ability and investigation depth. The findings of this work could be useful references for antenna selection and data processing in real GPR applications.
{"title":"Experimental Study on GPR Detection of Voids inside and behind Tunnel Linings","authors":"H. Qin, Xiongyao Xie, Yu Tang, Zhengzheng Wang","doi":"10.2113/JEEG18-085","DOIUrl":"https://doi.org/10.2113/JEEG18-085","url":null,"abstract":"Ground penetrating radar (GPR) is considered an effective tool to detect tunnel lining voids. In this paper, an experimental study was carried out using a physical tunnel lining model to evaluate the performances of different antenna frequencies. We built a 4.2 m–long, 4.2 m–wide, and 2.0 m–high experimental model to simulate the secondary lining, initial lining, and surrounding rock of a tunnel structure. In the model, we created four categories of voids, which are voids in secondary and initial linings, a delamination between the secondary and initial linings, a delamination between the initial lining and sand, and a void buried in the sand, to simulate real cases in tunnel engineering. The GPR wave velocities in the sand and concrete of the model were measured using the reflection method for the calibration of void depth. We employed a commercial GPR system equipped with antennae of different centre frequencies to detect the voids. GPR data were processed using a conventional data processing flow, and the performances of different frequencies were examined. The results show that the 1000 MHz centre frequency GPR is capable of characterizing shallow buried voids in the secondary lining but is not able to penetrate into the initial lining. The 250 MHz centre frequency GPR system is not advised to detect voids in or behind tunnel linings due to its low resolving power for voids of centimetre sizes. The 500 MHz centre frequency GPR system is optimal for void detection because it demonstrated a balanced performance of resolving ability and investigation depth. The findings of this work could be useful references for antenna selection and data processing in real GPR applications.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"28 1","pages":"65-74"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87414285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Editor's Foreword","authors":"D. Rucker","doi":"10.2113/jeeg25.1.iii","DOIUrl":"https://doi.org/10.2113/jeeg25.1.iii","url":null,"abstract":"","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"58 1","pages":""},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85193339","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Following our previous studies of the Differential Target Antenna Coupling (DTAC) method with horizontal and vertical arrays for EM surveys, in this paper we study the application of the DTAC method to a different configuration, where a large, stationary transmitter loop is on the ground surface. We then run profile lines inside this loop. The DTAC method is effective in eliminating errors due to the large variations in the primary field along profile lines within the transmitting loop. Operational tests show that we obtain more diagnostic DTAC anomalies over buried targets than using just the Bx and By data. The DTAC method also produces smaller false-alarm targets due to background geology variations, compared with Bz measurements. The DTAC method can be used with either time- or frequency-domain data and the receiver can be moved on the ground or deployed from an airborne vehicle, such as a drone.
{"title":"Differential Target Antenna Coupling (DTAC) EM Surveying with Stationary Transmitter Loop and Moving In-Loop Receivers","authors":"B. Sternberg","doi":"10.2113/JEEG19-034","DOIUrl":"https://doi.org/10.2113/JEEG19-034","url":null,"abstract":"Following our previous studies of the Differential Target Antenna Coupling (DTAC) method with horizontal and vertical arrays for EM surveys, in this paper we study the application of the DTAC method to a different configuration, where a large, stationary transmitter loop is on the ground surface. We then run profile lines inside this loop. The DTAC method is effective in eliminating errors due to the large variations in the primary field along profile lines within the transmitting loop. Operational tests show that we obtain more diagnostic DTAC anomalies over buried targets than using just the Bx and By data. The DTAC method also produces smaller false-alarm targets due to background geology variations, compared with Bz measurements. The DTAC method can be used with either time- or frequency-domain data and the receiver can be moved on the ground or deployed from an airborne vehicle, such as a drone.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"47 1","pages":"111-127"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82594473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Cai Yang, Sheng-dong Liu, Enjie Ding, Haiping Yang, Ji-Fu Xie
With the continuous development of urban underground space, non-destructive methods for diaphragm wall leakage detection are becoming increasingly important. Recent studies have shown that the apparent resistivity, stimulated current, and self-potential can be used as indicator parameters for non-destructive diaphragm wall leak detection. The diaphragm wall seepage evaluation of a subway station was carried out using the above indicator parameters. The response characteristics of apparent resistivity, stimulated current, and self-potential were obtained before and after excavating the diaphragm wall. The results obtained by this study reveal that an area is very likely to be a seepage area when there are significant differences amongst the three measurement parameters. The self-potential is greatly affected by field interference; the stimulated current is a direct sign of seepage, and indicates that seepage occurs when the stimulated current increases; the apparent resistivity macroscopically indicates rupture or seepage in the diaphragm wall. The field experiment verified the feasibility of detecting diaphragm wall seepage using coupled analysis based on electrical resistivity and self-potential methods.
{"title":"Evaluation of Electrical Resistivity for Non-destructive Seepage Detection on an Urban Underground Diaphragm Wall","authors":"Cai Yang, Sheng-dong Liu, Enjie Ding, Haiping Yang, Ji-Fu Xie","doi":"10.2113/jeeg18-091","DOIUrl":"https://doi.org/10.2113/jeeg18-091","url":null,"abstract":"With the continuous development of urban underground space, non-destructive methods for diaphragm wall leakage detection are becoming increasingly important. Recent studies have shown that the apparent resistivity, stimulated current, and self-potential can be used as indicator parameters for non-destructive diaphragm wall leak detection. The diaphragm wall seepage evaluation of a subway station was carried out using the above indicator parameters. The response characteristics of apparent resistivity, stimulated current, and self-potential were obtained before and after excavating the diaphragm wall. The results obtained by this study reveal that an area is very likely to be a seepage area when there are significant differences amongst the three measurement parameters. The self-potential is greatly affected by field interference; the stimulated current is a direct sign of seepage, and indicates that seepage occurs when the stimulated current increases; the apparent resistivity macroscopically indicates rupture or seepage in the diaphragm wall. The field experiment verified the feasibility of detecting diaphragm wall seepage using coupled analysis based on electrical resistivity and self-potential methods.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"40 1","pages":"1-14"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85899906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We have developed an algorithm to obtain the model parameters for two co-axial structures from self-potential data. The method uses the first numerical horizontal derivatives calculated from the observed self-potential anomaly employing filters of sequential window lengths (s-values) so as to gauge the model constraints for the shallow and deep structures. In addition, this algorithm uses a standard inversion method for solving a non-linear equation based on the lowest root-mean-square (RMS) error of the estimated model parameters. The body constraints are the depth, polarization angle and electric dipole moment of each structure. Our approach models the self-potential dataset as an aggregation of spheres, horizontal cylinders, and vertical cylinders. These simple bodies are used to approximate, without a priori expectations, the furthermost plausible position and/or area of intersection. In other words, the bodies are used to estimate the true values of the source parameters for the two-co-axial bodies at different s-values. Minimizing the RMS error has the advantage of optimizing all model factors. The proposed technique is tested using a numerical model with and without noise and on self-potential field data acquired at a site in Germany. In all cases, the assessed body parameters are reasonable approximations of the known values.
{"title":"Self-potential Data Interpretation for Two Co-axial Structures Utilizing the RMS Parameter","authors":"K. Essa, Z. E. Diab, Mahmoud Elhussein","doi":"10.2113/JEEG19-017","DOIUrl":"https://doi.org/10.2113/JEEG19-017","url":null,"abstract":"We have developed an algorithm to obtain the model parameters for two co-axial structures from self-potential data. The method uses the first numerical horizontal derivatives calculated from the observed self-potential anomaly employing filters of sequential window lengths (s-values) so as to gauge the model constraints for the shallow and deep structures. In addition, this algorithm uses a standard inversion method for solving a non-linear equation based on the lowest root-mean-square (RMS) error of the estimated model parameters. The body constraints are the depth, polarization angle and electric dipole moment of each structure. Our approach models the self-potential dataset as an aggregation of spheres, horizontal cylinders, and vertical cylinders. These simple bodies are used to approximate, without a priori expectations, the furthermost plausible position and/or area of intersection. In other words, the bodies are used to estimate the true values of the source parameters for the two-co-axial bodies at different s-values. Minimizing the RMS error has the advantage of optimizing all model factors. The proposed technique is tested using a numerical model with and without noise and on self-potential field data acquired at a site in Germany. In all cases, the assessed body parameters are reasonable approximations of the known values.","PeriodicalId":15748,"journal":{"name":"Journal of Environmental and Engineering Geophysics","volume":"12 1","pages":"15-23"},"PeriodicalIF":1.0,"publicationDate":"2020-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85984321","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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