The Salt Range (SR) is an ENE-WSW trending fault bend fold that form the range front of the Himalayan fold and thrust belt in Pakistan. The research is carried out in the Eastern Salt Range (ESR) with the objective to determine the paleostress inversion from reduced stress tensors by using fracture data. The surface morphology of the fold is predominantly shaped by Eocene limestone that provide best exposure of joint surfaces that can be used for kinematic and dynamic analysis. We adopted a classical circle inventory method in the field and collected orientation data (dip amount, direction, and strike) from 7 localities (outcrop stations) of the Eocene Sakesar Limestone. Three prominent fracture trends are present in the study area namely, FS-1; (E-W), FS-2; (ENE-WSW) and FS-3; (NNE-SSW). For stress analysis and data processing we used the Tensor Program of Delvaux and Sperner (2003) and calculated seven stress fields by the Right Dihedron Method. The orientations of the principal stress axes (ϭ1, ϭ2, ϭ3) and Stress Ratio (R) depicts ϭ1(Shmax) and ϭ2 are sub-horizontal while ϭ3 is vertical in all stress tensors. The paleostress results show that ϭ1(Shmax) oriented NNE-SSW belonging to a compressive regime. It is suggested that ϭ1 developed more or less perpendicular to the trend of SRT and other relevant structures in the Potwar Plateau.
{"title":"Paleostress and outcrop fracture analysis along Himalayan Foothills (Eastern Salt Range), Potwar Plateau, NW Himalaya, Pakistan","authors":"Hassan Mehmood","doi":"10.13168/AGG.2021.0013","DOIUrl":"https://doi.org/10.13168/AGG.2021.0013","url":null,"abstract":"The Salt Range (SR) is an ENE-WSW trending fault bend fold that form the range front of the Himalayan fold and thrust belt in Pakistan. The research is carried out in the Eastern Salt Range (ESR) with the objective to determine the paleostress inversion from reduced stress tensors by using fracture data. The surface morphology of the fold is predominantly shaped by Eocene limestone that provide best exposure of joint surfaces that can be used for kinematic and dynamic analysis. We adopted a classical circle inventory method in the field and collected orientation data (dip amount, direction, and strike) from 7 localities (outcrop stations) of the Eocene Sakesar Limestone. Three prominent fracture trends are present in the study area namely, FS-1; (E-W), FS-2; (ENE-WSW) and FS-3; (NNE-SSW). For stress analysis and data processing we used the Tensor Program of Delvaux and Sperner (2003) and calculated seven stress fields by the Right Dihedron Method. The orientations of the principal stress axes (ϭ1, ϭ2, ϭ3) and Stress Ratio (R) depicts ϭ1(Shmax) and ϭ2 are sub-horizontal while ϭ3 is vertical in all stress tensors. The paleostress results show that ϭ1(Shmax) oriented NNE-SSW belonging to a compressive regime. It is suggested that ϭ1 developed more or less perpendicular to the trend of SRT and other relevant structures in the Potwar Plateau.","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47727320","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Repeated geodetic observations were applied in mining location Louky near Karviná to detect surface changes from undermining in complex geo-mechanical conditions. Analyses of the subsidence magnitude and the length and direction of horizontal displacements showed that the subsidence trough was formed unevenly not only due to the position of the exploited local longwall panels and their different size but also showed a notable effect of the dominant tectonic fault. The significantly uneven development of the subsidence trough negatively affects line constructions. Terrain deformations of the road and stream pipeline were computed and classified into the building site categories according to the Czech standard ČSN 73 0039. The course of individual deformations in the monitored locality is influenced by a complex geo-mechanical situation. While the course of the subsidence curves is continuous at the observed pipeline and the classification of individual sections into building site categories corresponds with that, the road profile points out a more complex development of surface deformations. At the end of the observed period, 5 % of the profiles’ sections fell into category III (medium intensity), 49 % into category IV (moderate intensity) and 32 % stayed in category V (very moderate intensity of mining effects). ARTICLE INFO
{"title":"Analysis of surface changes from undermining and building site categorization: The case study in mining location Louky near Karvina","authors":"H. Doležalová","doi":"10.13168/AGG.2021.0009","DOIUrl":"https://doi.org/10.13168/AGG.2021.0009","url":null,"abstract":"Repeated geodetic observations were applied in mining location Louky near Karviná to detect surface changes from undermining in complex geo-mechanical conditions. Analyses of the subsidence magnitude and the length and direction of horizontal displacements showed that the subsidence trough was formed unevenly not only due to the position of the exploited local longwall panels and their different size but also showed a notable effect of the dominant tectonic fault. The significantly uneven development of the subsidence trough negatively affects line constructions. Terrain deformations of the road and stream pipeline were computed and classified into the building site categories according to the Czech standard ČSN 73 0039. The course of individual deformations in the monitored locality is influenced by a complex geo-mechanical situation. While the course of the subsidence curves is continuous at the observed pipeline and the classification of individual sections into building site categories corresponds with that, the road profile points out a more complex development of surface deformations. At the end of the observed period, 5 % of the profiles’ sections fell into category III (medium intensity), 49 % into category IV (moderate intensity) and 32 % stayed in category V (very moderate intensity of mining effects). ARTICLE INFO","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43847776","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study integrates remote sensing and geophysical data to identify the hydrological conditions of the Naqab reservoir watershed. The main objectives of this study are identification and the interpretation of subsurface structures and their impact on groundwater flow, the relationships between structures and groundwater and the optimum way for watershed management in this sub-basin. Geophysical data including, ground magnetic survey and 1D electrical resistivity sounding helped in identifying the lithology and delineating zones of groundwater occurrence. The magnetic data delineated the basement rock, aided in characterizing the geometry of the subsurface structures that control the land surface features and constrain groundwater flow system. The interpreted subsurface structure elements include six sets of faults trending NE-SW, NW-SE, NWW-SEE, NEE-SWW, N-S and E-W. The basement depth was estimated at zero at the southern part and about 5187 m at the northern part. Two aquifer systems were characterized, the shallow aquifer of the Wata Formation (Upper Cretaceous) and the deep aquifer of the Malha Formation (Lower Cretaceous). The probability of groundwater occurrence increases towards the central part of the study area to north direction, where the thickness of the sedimentary basin reaches its maximum at the center of the study area. Different trends of faults were interpreted from the geo- electrical cross-sections along two transects. Three patterns of faults were characterized including step faults, graben faults and horst faults. These faults could be indicated on the geo-electrical section by a marked difference in the layers` thicknesses. The magnetic data confirmed the locations of the faults delineated by the electrical resistivity profiles. The outlined faults are trending mainly in NE-SW, NW-SE, NWW-SEE, NEE-SWW and E-W directions. Lineament structures delineation and drainage pattern analysis were evaluated and interpreted from the analysis of remote sensing (RS) data and geographic information system (GIS) technique. The SRTM-DEM (Shuttle Radar Topographic Mission-Digital Elevation Model) was also utilized to automatically identify and extract drainage network. Interpretation and analysis of the inferred lineament structures indicate the presence of a number of main lineament populations that trends: NE-SW, NW-SE, NNW-SSE, NWW-SEE, E-W and N-S. Meanwhile, the interpretation and analysis of drainage pattern network indicate the presence of three main lineament structures that trends: NW-SE, NE-SW and NWW-SEE. Azimuth distribution analysis of both the measured structures and drainage channels shows similar trends, except for very few differences in the prevailing trends. Similarity in orientation of lineament structures, drainage system, and subsurface structural trends were recognized in the area under study. In conclusion, the integration between remote sensing and geophysical data revealed a close matching between the surface st
{"title":"Water resources exploration and management based on remote sensing and geophysical data analysis: \u0000Al-Naqab Watershed, East Central Sinai, Egypt","authors":"U. Massoud","doi":"10.13168/AGG.2021.0008","DOIUrl":"https://doi.org/10.13168/AGG.2021.0008","url":null,"abstract":"This study integrates remote sensing and geophysical data to identify the hydrological conditions of the Naqab reservoir watershed. The main objectives of this study are identification and the interpretation of subsurface structures and their impact on groundwater flow, the relationships between structures and groundwater and the optimum way for watershed management in this sub-basin. Geophysical data including, ground magnetic survey and 1D electrical resistivity sounding helped in identifying the lithology and delineating zones of groundwater occurrence. The magnetic data delineated the basement rock, aided in characterizing the geometry of the subsurface structures that control the land surface features and constrain groundwater flow system. The interpreted subsurface structure elements include six sets of faults trending NE-SW, NW-SE, NWW-SEE, NEE-SWW, N-S and E-W. The basement depth was estimated at zero at the southern part and about 5187 m at the northern part. Two aquifer systems were characterized, the shallow aquifer of the Wata Formation (Upper Cretaceous) and the deep aquifer of the Malha Formation (Lower Cretaceous). The probability of groundwater occurrence increases towards the central part of the study area to north direction, where the thickness of the sedimentary basin reaches its maximum at the center of the study area. Different trends of faults were interpreted from the geo- electrical cross-sections along two transects. Three patterns of faults were characterized including step faults, graben faults and horst faults. These faults could be indicated on the geo-electrical section by a marked difference in the layers` thicknesses. The magnetic data confirmed the locations of the faults delineated by the electrical resistivity profiles. The outlined faults are trending mainly in NE-SW, NW-SE, NWW-SEE, NEE-SWW and E-W directions. Lineament structures delineation and drainage pattern analysis were evaluated and interpreted from the analysis of remote sensing (RS) data and geographic information system (GIS) technique. The SRTM-DEM (Shuttle Radar Topographic Mission-Digital Elevation Model) was also utilized to automatically identify and extract drainage network. Interpretation and analysis of the inferred lineament structures indicate the presence of a number of main lineament populations that trends: NE-SW, NW-SE, NNW-SSE, NWW-SEE, E-W and N-S. Meanwhile, the interpretation and analysis of drainage pattern network indicate the presence of three main lineament structures that trends: NW-SE, NE-SW and NWW-SEE. Azimuth distribution analysis of both the measured structures and drainage channels shows similar trends, except for very few differences in the prevailing trends. Similarity in orientation of lineament structures, drainage system, and subsurface structural trends were recognized in the area under study. In conclusion, the integration between remote sensing and geophysical data revealed a close matching between the surface st","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45854204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A growing interest in the field of coal bed methane (CBM) extraction in Poland shows the demand for rock mechanics data, used to design hydraulic fracturing operations. The elastic response of the rock is typically determined by sonic logging calibrated with laboratory tests. This paper presents the laboratory ultrasonic measurements of the core samples, performed to determine the elastic moduli and brittleness index (BI) of the coal. Tests were performed on 20 core plugs from four coal mines located in the central and southern part of the Upper Silesian Coal Basin (USCB), Poland, characterized by varied maceral composition and mineral additives. The samples were cored out in three directions: perpendicular, parallel, and at a 45° angle to the bedding planes, and tested with the given effective pressure. The majority of the samples were saturated by water with a potassium chloride additive (swelling inhibitor). A Pand S-wave velocity upward trend was observed when the mineral content in the samples increased. Elevated velocities in samples of high mineral content resulted in exceeding the Ed to vd limits for coal as proposed in literature. With increased BI, upward trends in the liptinite and inertinite content as well as a downward trend in the vitrinite content were observed. The dynamic elastic moduli of the measured samples were compared to the available literature data. ARTICLE INFO
{"title":"Brittleness index of coal from the Upper Silesian Coal Basin","authors":"Rafał Moska","doi":"10.13168/AGG.2021.0007","DOIUrl":"https://doi.org/10.13168/AGG.2021.0007","url":null,"abstract":"A growing interest in the field of coal bed methane (CBM) extraction in Poland shows the demand for rock mechanics data, used to design hydraulic fracturing operations. The elastic response of the rock is typically determined by sonic logging calibrated with laboratory tests. This paper presents the laboratory ultrasonic measurements of the core samples, performed to determine the elastic moduli and brittleness index (BI) of the coal. Tests were performed on 20 core plugs from four coal mines located in the central and southern part of the Upper Silesian Coal Basin (USCB), Poland, characterized by varied maceral composition and mineral additives. The samples were cored out in three directions: perpendicular, parallel, and at a 45° angle to the bedding planes, and tested with the given effective pressure. The majority of the samples were saturated by water with a potassium chloride additive (swelling inhibitor). A Pand S-wave velocity upward trend was observed when the mineral content in the samples increased. Elevated velocities in samples of high mineral content resulted in exceeding the Ed to vd limits for coal as proposed in literature. With increased BI, upward trends in the liptinite and inertinite content as well as a downward trend in the vitrinite content were observed. The dynamic elastic moduli of the measured samples were compared to the available literature data. ARTICLE INFO","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41504273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this study, the analysis of ground gravity data (from the Libyan Petroleum Institute) and aeromagnetic data (from the African Magnetic Mapping Project) are used to delineate the structure elements and basement depth within the Jifara plain, northwest Libya. A high-pass filter and a reduction-to-the-pole (RTP) transformation are applied to the gravity and aeromagnetic data respectively. The Total horizontal gradient and Centre for Exploration Targeting (CET) grid analysis are applied to gravity datasets. Werner deconvolution is applied to the RTP magnetic data. One 2-D forward modelling profile is applied to gravity and magnetic dataset. The results show gravity anomaly highs and magnetic anomaly with different structure trends. Werner deconvolution profile shows a high-density intrusion (about 1.8 km from the surface) within the sedimentary sequence. The intrusion may be the result of the Eocene volcanic activities near the Gharyan region. The 2-D model shows that the basement depth of Jifara plain ranges from 2.8 to 3.0 km. The integration results of the gravity and magnetic dataset reflect various periods of tectonic activities within Jifara plain and the adjacent area.
{"title":"Delineation of structure elements and the basement depth at the Jifara plain NW LIBYA using integration application of potential field dataset","authors":"Fouzie Trepil","doi":"10.13168/AGG.2021.0006","DOIUrl":"https://doi.org/10.13168/AGG.2021.0006","url":null,"abstract":"In this study, the analysis of ground gravity data (from the Libyan Petroleum Institute) and aeromagnetic data (from the African Magnetic Mapping Project) are used to delineate the structure elements and basement depth within the Jifara plain, northwest Libya. A high-pass filter and a reduction-to-the-pole (RTP) transformation are applied to the gravity and aeromagnetic data respectively. The Total horizontal gradient and Centre for Exploration Targeting (CET) grid analysis are applied to gravity datasets. Werner deconvolution is applied to the RTP magnetic data. One 2-D forward modelling profile is applied to gravity and magnetic dataset. The results show gravity anomaly highs and magnetic anomaly with different structure trends. Werner deconvolution profile shows a high-density intrusion (about 1.8 km from the surface) within the sedimentary sequence. The intrusion may be the result of the Eocene volcanic activities near the Gharyan region. The 2-D model shows that the basement depth of Jifara plain ranges from 2.8 to 3.0 km. The integration results of the gravity and magnetic dataset reflect various periods of tectonic activities within Jifara plain and the adjacent area.","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41835346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The dynamic properties of soil deposits subjected to dynamic loading, such as the shear modulus G and material damping ratio D, are important parameters in ground response seismic analysis. In seasonally frozen regions, these properties can be significantly affected by microstructural changes that occur during freeze-thaw cycles. The current study evaluated the dynamic properties of clayey soil exposed to freeze-thaw cycles. Dynamic triaxial testing was conducted to determine the influence of mean effective consolidation stress, cyclic stress ratio, loading frequency, and freeze-thaw cycles on G-γ and D-γ curves. Scanning electron microscopy (SEM) was carried out to investigate microstructural changes in the clay soil fabric. The results indicate the freeze-thaw process has an important effect on dynamic properties of the soil. The dynamic shear modulus increases with increasing effective confining pressure, loading frequency, and confining pressure, and decreases with increasing number of freeze-thaw cycles. Development of more voids between clay particles after ice lens formation during these cycles results in an increase in the damping ratio, but this trend decreases with increasing confining pressure. Increasing the loading frequency increases or decreases the damping ratio depending upon the mean effective confining pressure and number of freeze-thaw cycles. ARTICLE INFO
{"title":"Shear modulus and damping ratio of clay soil under repeated freeze-thaw cycles","authors":"M. Roustaei","doi":"10.13168/AGG.2021.0005","DOIUrl":"https://doi.org/10.13168/AGG.2021.0005","url":null,"abstract":"The dynamic properties of soil deposits subjected to dynamic loading, such as the shear modulus G and material damping ratio D, are important parameters in ground response seismic analysis. In seasonally frozen regions, these properties can be significantly affected by microstructural changes that occur during freeze-thaw cycles. The current study evaluated the dynamic properties of clayey soil exposed to freeze-thaw cycles. Dynamic triaxial testing was conducted to determine the influence of mean effective consolidation stress, cyclic stress ratio, loading frequency, and freeze-thaw cycles on G-γ and D-γ curves. Scanning electron microscopy (SEM) was carried out to investigate microstructural changes in the clay soil fabric. The results indicate the freeze-thaw process has an important effect on dynamic properties of the soil. The dynamic shear modulus increases with increasing effective confining pressure, loading frequency, and confining pressure, and decreases with increasing number of freeze-thaw cycles. Development of more voids between clay particles after ice lens formation during these cycles results in an increase in the damping ratio, but this trend decreases with increasing confining pressure. Increasing the loading frequency increases or decreases the damping ratio depending upon the mean effective confining pressure and number of freeze-thaw cycles. ARTICLE INFO","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45361094","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Soil nailing is a reliable method of stabilising earth and rock slopes, but the geometrical layout of soil nails has not been well studied. The current research examined the effect of the geometrical layout of soil nails using analytical and physical modelling. The results of limit equilibrium analysis for different nail layouts are presented. The target gravity level was 50 g for centrifuge models and all models had a safety factor of 1.35 at this level. The parameters studied were base nail length, angle of nail tail extension, horizontal spacing of nails, and nail density. The limit equilibrium results showed that, when longer nails were used, the nail density could be decreased. The results of centrifuge modelling confirmed that different layouts at a similar safety factor did not show similar levels of displacement. Also, nail density was the most influential parameter affecting soil-nailed wall performance. An empirical relationship was observed between displacements of the wall crest and nail density. An interesting similarity was observed between the predicted slip surface and the slip surface that formed during physical modelling. ARTICLE INFO
{"title":"Studying the effect of geometrical nail layout on the performance of soil-nailed walls: Physical and numerical modeling","authors":"M. Sabermahani","doi":"10.13168/AGG.2021.0003","DOIUrl":"https://doi.org/10.13168/AGG.2021.0003","url":null,"abstract":"Soil nailing is a reliable method of stabilising earth and rock slopes, but the geometrical layout of soil nails has not been well studied. The current research examined the effect of the geometrical layout of soil nails using analytical and physical modelling. The results of limit equilibrium analysis for different nail layouts are presented. The target gravity level was 50 g for centrifuge models and all models had a safety factor of 1.35 at this level. The parameters studied were base nail length, angle of nail tail extension, horizontal spacing of nails, and nail density. The limit equilibrium results showed that, when longer nails were used, the nail density could be decreased. The results of centrifuge modelling confirmed that different layouts at a similar safety factor did not show similar levels of displacement. Also, nail density was the most influential parameter affecting soil-nailed wall performance. An empirical relationship was observed between displacements of the wall crest and nail density. An interesting similarity was observed between the predicted slip surface and the slip surface that formed during physical modelling. ARTICLE INFO","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43262175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study highlights the groundwater evaluation of the Nubian sandstone aquifers regarding assessing the main structural elements, trends, and depth to the basement rocks that control the groundwater aquifers in Egypt's central Sinai area. Gravity and magnetic data were analyzed using different techniques, such as wavenumber filtering, least-squares separation techniques, and tilt derivatives. Euler deconvolution with different structural indexes (SI), power spectrum analyses, 3-D crustal modeling. The deep-seated structures affecting the study area, and the basement depth, which range between 1170 and 4590 m., have been utilized. The main structural trends affecting the study area were delineated to control the groundwater aquifer's regional geometry. Moreover, it was found that the NorthWest-SouthEast trend direction – Suez Gulf trend – was caused by primary shear, and the NorthEast-SouthWest trend direction – Aqaba Gulf trend – was caused by the secondary shear. The direction of each trend's lateral movement was to the right and the left, respectively. Meanwhile, the geoelectrical resistivity measurements were also utilized to determine the ground water-bearing formations using eighteen deep vertical electrical soundings (VES) stations. The results revealed the depth to the uppermost part of the Nubian sandstone aquifer ranging between 598 and 1106 m; the combination of the depth to the uppermost part of the Nubian aquifer, the depth of the basement relief map revealed that the aquifer thickness varies from 430 to 3750 m, and the resistivity values ranging between 22 and 214 Ω.m. ARTICLE INFO
{"title":"Application of the multi potential geophysical techniques for groundwater evaluation in a part of Central Sinai Peninsula_ Egypt","authors":"Hussain Tawfik El-Badrawy","doi":"10.13168/AGG.2021.0004","DOIUrl":"https://doi.org/10.13168/AGG.2021.0004","url":null,"abstract":"This study highlights the groundwater evaluation of the Nubian sandstone aquifers regarding assessing the main structural elements, trends, and depth to the basement rocks that control the groundwater aquifers in Egypt's central Sinai area. Gravity and magnetic data were analyzed using different techniques, such as wavenumber filtering, least-squares separation techniques, and tilt derivatives. Euler deconvolution with different structural indexes (SI), power spectrum analyses, 3-D crustal modeling. The deep-seated structures affecting the study area, and the basement depth, which range between 1170 and 4590 m., have been utilized. The main structural trends affecting the study area were delineated to control the groundwater aquifer's regional geometry. Moreover, it was found that the NorthWest-SouthEast trend direction – Suez Gulf trend – was caused by primary shear, and the NorthEast-SouthWest trend direction – Aqaba Gulf trend – was caused by the secondary shear. The direction of each trend's lateral movement was to the right and the left, respectively. Meanwhile, the geoelectrical resistivity measurements were also utilized to determine the ground water-bearing formations using eighteen deep vertical electrical soundings (VES) stations. The results revealed the depth to the uppermost part of the Nubian sandstone aquifer ranging between 598 and 1106 m; the combination of the depth to the uppermost part of the Nubian aquifer, the depth of the basement relief map revealed that the aquifer thickness varies from 430 to 3750 m, and the resistivity values ranging between 22 and 214 Ω.m. ARTICLE INFO","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44915218","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Azad Kashmir has undergone sever landslide episodes in the past. The main reasons behind the occurrence of landslides in this area are heavy rainfall, weak geological strata, seismic zones and active faults. Several episodes of roads blockage due to landslide is one of the major problem in this area, therefore, this study is carried out for landslide susceptibility analysis along the roads of Kotli to Trar Khel, Azad Kashmir, NW Sub-Himalayas. Geographic information system (GIS) is used to interpret remote sensing, geological strata and topographical data. Total ten anthropogenic and physical factors (aspects, fault, lithology, drainage density, curvature, distance to roads, landuse landcover, slope, seismic and elevation) were examined by Multi-criteria Decision Analysis (MCDA) technique. The thematic layers of all factors were prepared for the preparation of the final susceptibility map by using a weighted overlay method (WOM). The susceptibility map classified the study area into four susceptible classes of low, moderate, high and very high. The spatial analysis and result outcomes depicted that active faults, slope gradient and landuse landcover may facilitate landslide phenomena. The results were verified by landslide density analyses (LDA), receiver operator characteristics (ROC) and area under curve (AUC) with predictive accuracy of 77 % that is rated as satisfactory by many researchers.
{"title":"Landslide detection and susceptibility mapping using geological and remote sensing data: A case study of Azad Kashmir, NW Sub-Himalayas","authors":"M. Zeeshan","doi":"10.13168/AGG.2021.0002","DOIUrl":"https://doi.org/10.13168/AGG.2021.0002","url":null,"abstract":"Azad Kashmir has undergone sever landslide episodes in the past. The main reasons behind the occurrence of landslides in this area are heavy rainfall, weak geological strata, seismic zones and active faults. Several episodes of roads blockage due to landslide is one of the major problem in this area, therefore, this study is carried out for landslide susceptibility analysis along the roads of Kotli to Trar Khel, Azad Kashmir, NW Sub-Himalayas. Geographic information system (GIS) is used to interpret remote sensing, geological strata and topographical data. Total ten anthropogenic and physical factors (aspects, fault, lithology, drainage density, curvature, distance to roads, landuse landcover, slope, seismic and elevation) were examined by Multi-criteria Decision Analysis (MCDA) technique. The thematic layers of all factors were prepared for the preparation of the final susceptibility map by using a weighted overlay method (WOM). The susceptibility map classified the study area into four susceptible classes of low, moderate, high and very high. The spatial analysis and result outcomes depicted that active faults, slope gradient and landuse landcover may facilitate landslide phenomena. The results were verified by landslide density analyses (LDA), receiver operator characteristics (ROC) and area under curve (AUC) with predictive accuracy of 77 % that is rated as satisfactory by many researchers.","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48021921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In order to convert ellipsoidal heights obtained by the Global Navigation Satellite System (GNSS) to orthometric heights, it is necessary to know the distance between the ellipsoidal and geoid surface, called the geoid undulation. The geoid undulation can be predicted using emerging mathematics tools and algorithms. The objective of this study was to develop a model for predicting the geoid undulation using Gaussian Process Regression (GPR), one of the soft machine learning algorithms having different covariance functions. This method was then compared with the radial basis function neural network (RBFNN), generalized regression neural network (GRNN), and the interpolation method of inverse distance to a power (IDP) with the power of 1, 2, 3, 4, and 5. First, 70 % of GNSS/leveling data (422 points) were used in the training phase. The remaining 185 points were used as testing data to check the effectiveness of the constructed model. In the GPR modeling, ten covariance functions (Materniso d= 1, 3, 5; Maternard d= 1, 3, 5; SEiso; SEard; RQiso; and RQard) were tested for prediction on this dataset. The GPR based on the Materniso (d = 1) covariance function model was introduced as an effective method for predicting geoid undulation and provided the best results (RMSE = 8.32 cm, MAE = 5.51 cm, R2 = 0.98968) when compared with the other developed GPR models. In addition, the statistical findings showed that the accuracy of all the GPR models was also better in predicting geoid undulation than the RBFNN, GRNN, and IDP with the power of 1, 2, 3, 4, and 5. ARTICLE INFO
为了将全球导航卫星系统(GNSS)获得的椭球面高度转换为正等高，需要知道椭球面与大地水准面之间的距离，称为大地水准面波动。大地水准面起伏可以用新兴的数学工具和算法来预测。本研究的目的是建立一个利用高斯过程回归(GPR)预测大地水准面波动的模型，高斯过程回归是一种具有不同协方差函数的软机器学习算法。将该方法与径向基函数神经网络(RBFNN)、广义回归神经网络(GRNN)以及1、2、3、4、5次幂的距离逆幂插值方法(IDP)进行比较。首先，在训练阶段使用了70%的GNSS/水准数据(422个点)。剩余的185个点作为检验数据，检验所构建模型的有效性。在GPR建模中，10个协方差函数(Materniso d= 1,3,5;母亲d= 1,3,5;清洁;SEard;RQiso;和RQard)在该数据集上进行了预测测试。采用Materniso (d = 1)协方差函数模型预测大地水准面波动是一种有效的方法，与已有的GPR模型相比，RMSE = 8.32 cm, MAE = 5.51 cm, R2 = 0.98968。此外，统计结果表明，所有GPR模型在预测大地水准面波动方面的精度也优于RBFNN、GRNN和IDP(1、2、3、4、5次幂)。条信息
{"title":"Geoid undulation prediction using Gaussian Processes Regression: A case study in a local region in Turkey","authors":"B. Konakoglu","doi":"10.13168/AGG.2021.0001","DOIUrl":"https://doi.org/10.13168/AGG.2021.0001","url":null,"abstract":"In order to convert ellipsoidal heights obtained by the Global Navigation Satellite System (GNSS) to orthometric heights, it is necessary to know the distance between the ellipsoidal and geoid surface, called the geoid undulation. The geoid undulation can be predicted using emerging mathematics tools and algorithms. The objective of this study was to develop a model for predicting the geoid undulation using Gaussian Process Regression (GPR), one of the soft machine learning algorithms having different covariance functions. This method was then compared with the radial basis function neural network (RBFNN), generalized regression neural network (GRNN), and the interpolation method of inverse distance to a power (IDP) with the power of 1, 2, 3, 4, and 5. First, 70 % of GNSS/leveling data (422 points) were used in the training phase. The remaining 185 points were used as testing data to check the effectiveness of the constructed model. In the GPR modeling, ten covariance functions (Materniso d= 1, 3, 5; Maternard d= 1, 3, 5; SEiso; SEard; RQiso; and RQard) were tested for prediction on this dataset. The GPR based on the Materniso (d = 1) covariance function model was introduced as an effective method for predicting geoid undulation and provided the best results (RMSE = 8.32 cm, MAE = 5.51 cm, R2 = 0.98968) when compared with the other developed GPR models. In addition, the statistical findings showed that the accuracy of all the GPR models was also better in predicting geoid undulation than the RBFNN, GRNN, and IDP with the power of 1, 2, 3, 4, and 5. ARTICLE INFO","PeriodicalId":50899,"journal":{"name":"Acta Geodynamica et Geomaterialia","volume":" ","pages":""},"PeriodicalIF":0.9,"publicationDate":"2021-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42689856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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