Pub Date : 2022-06-28DOI: 10.15625/2615-9783/17245
Tuan Nguyen Thanh, Duc Ho Quang, Bat Le Thai, Tuan Le Anh, Chien Nguyen Quyet, Trung Lai Quang, Stanslaus Kikuvi Kyenze, Chi Tran Thuy
A quantitative soil classification system (SCS) has been the aim of generations of Vietnam soil scientists. The SCS is a system of harmonizing the traditional Vietnam SCSs and creating a capability for international exchange. Up to now, there are three partially developed Vietnam official SCSs and three Vietnam semi-quantitative ones. This article aims to upgrade the Vietnam semi-quantitative SCS based on Vietnam's traditional pedogenetic (qualitative) and the World Reference Base for Soil Resources in 2014 (quantitative). For this purpose, a study was conducted to compare and analyze the correlation between the published Vietnam semi-quantitative SCSs and the official ones. Six SCSs were compared and analyzed. The results show that the Vietnam semi-quantitative SCS-2006 was selected to continue adapting and updating. Apart from the necessary adjustments, the study added 12 diagnostic horizons, 4 diagnostic properties, 2 diagnostic materials, 2 soil groups, 11 soil types, and 37 soil sub-types in the Vietnam semi-quantitative SCS-2006. Finally, the Vietnam semi-quantitative SCS includes 25 soil groups, 86 soil types, 492 soil sub-types with 30 diagnostic horizons, 7 diagnostic properties, 6 diagnostic materials, 58 qualifiers, and 9 criteria for defining soil varieties. The system keeps the traditional aspects of Vietnam's official SCSs and allows the exchange of international soil information.
{"title":"Upgrading the Vietnam semi-quantitative soil classification system","authors":"Tuan Nguyen Thanh, Duc Ho Quang, Bat Le Thai, Tuan Le Anh, Chien Nguyen Quyet, Trung Lai Quang, Stanslaus Kikuvi Kyenze, Chi Tran Thuy","doi":"10.15625/2615-9783/17245","DOIUrl":"https://doi.org/10.15625/2615-9783/17245","url":null,"abstract":"A quantitative soil classification system (SCS) has been the aim of generations of Vietnam soil scientists. The SCS is a system of harmonizing the traditional Vietnam SCSs and creating a capability for international exchange. Up to now, there are three partially developed Vietnam official SCSs and three Vietnam semi-quantitative ones. This article aims to upgrade the Vietnam semi-quantitative SCS based on Vietnam's traditional pedogenetic (qualitative) and the World Reference Base for Soil Resources in 2014 (quantitative). For this purpose, a study was conducted to compare and analyze the correlation between the published Vietnam semi-quantitative SCSs and the official ones. Six SCSs were compared and analyzed. The results show that the Vietnam semi-quantitative SCS-2006 was selected to continue adapting and updating. Apart from the necessary adjustments, the study added 12 diagnostic horizons, 4 diagnostic properties, 2 diagnostic materials, 2 soil groups, 11 soil types, and 37 soil sub-types in the Vietnam semi-quantitative SCS-2006. Finally, the Vietnam semi-quantitative SCS includes 25 soil groups, 86 soil types, 492 soil sub-types with 30 diagnostic horizons, 7 diagnostic properties, 6 diagnostic materials, 58 qualifiers, and 9 criteria for defining soil varieties. The system keeps the traditional aspects of Vietnam's official SCSs and allows the exchange of international soil information.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41935226","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-24DOI: 10.15625/2615-9783/17240
Duong Hai Ha, Huong Thi Thanh Ngo, Phong Tran Van, Dam Nguyen Duc, Mohammadtaghi Avand, Duy Nguyen Huu, M. Amiri, Hiep Van Le, Indra Prakash, Pham Binh Thai
Groundwater potential assessment is essential for optimum utilization and recharge of groundwater resources for the proper development and management of an area. The main aim of this study is to develop an accurate groundwater potential map of the Dak Nong Province (Vietnam) using hybrid artificial intelligence models, which are a combination of Random Forest (RF) and its Ensemble Framework (AdaBoost - ABRF, Bagging - BRF and LogitBoost - LBRF). In this study, twelve conditioning factors, namely topography (aspect, elevation, Topographic Wetness Index - TWI, slope, and curvature), hydrology (infiltration and river density, rainfall, Sediment Transport Index - STI, Stream Power Index - SPI), land use, and soil were used to develop the models. Well, yield data was also utilized to develop and validate potential groundwater zones. One Rule (R) feature selection method was utilized to prioritize the importance of groundwater potential affecting parameters. The results indicated that the Average Merit (AM) of the rainfall factor was the highest (68.039), and river density was the lowest (53,969). Performance evaluation of ML models was done using standard statistical indicators, including Area Under the Receiver Operating Characteristic (ROC) curve (AUC). The results showed that all the four models performed well in the training (AUC ≥ 0.967) and testing (AUC ≥ 0.734) phases, but the performance of the ABRF (AUC=0.992) model is the best in the training phase, whereas LBRF is the best in the testing phase (AUC=0.776). The present model study would be helpful in the proper groundwater potential assessment and management of groundwater resources for sustainable development.
{"title":"Development and application of hybrid artificial intelligence models for groundwater potential mapping and assessment","authors":"Duong Hai Ha, Huong Thi Thanh Ngo, Phong Tran Van, Dam Nguyen Duc, Mohammadtaghi Avand, Duy Nguyen Huu, M. Amiri, Hiep Van Le, Indra Prakash, Pham Binh Thai","doi":"10.15625/2615-9783/17240","DOIUrl":"https://doi.org/10.15625/2615-9783/17240","url":null,"abstract":"Groundwater potential assessment is essential for optimum utilization and recharge of groundwater resources for the proper development and management of an area. The main aim of this study is to develop an accurate groundwater potential map of the Dak Nong Province (Vietnam) using hybrid artificial intelligence models, which are a combination of Random Forest (RF) and its Ensemble Framework (AdaBoost - ABRF, Bagging - BRF and LogitBoost - LBRF). In this study, twelve conditioning factors, namely topography (aspect, elevation, Topographic Wetness Index - TWI, slope, and curvature), hydrology (infiltration and river density, rainfall, Sediment Transport Index - STI, Stream Power Index - SPI), land use, and soil were used to develop the models. Well, yield data was also utilized to develop and validate potential groundwater zones. \u0000One Rule (R) feature selection method was utilized to prioritize the importance of groundwater potential affecting parameters. The results indicated that the Average Merit (AM) of the rainfall factor was the highest (68.039), and river density was the lowest (53,969). Performance evaluation of ML models was done using standard statistical indicators, including Area Under the Receiver Operating Characteristic (ROC) curve (AUC). The results showed that all the four models performed well in the training (AUC ≥ 0.967) and testing (AUC ≥ 0.734) phases, but the performance of the ABRF (AUC=0.992) model is the best in the training phase, whereas LBRF is the best in the testing phase (AUC=0.776). The present model study would be helpful in the proper groundwater potential assessment and management of groundwater resources for sustainable development. ","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41882359","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-28DOI: 10.15625/2615-9783/17178
Hoi Nguyen Dang, Dung Ngo Trung, A. Kuznetsov, Phuong Vu Le
Classification and mapping of marine-island landscapes according to an integrated approach not only clarifies the structure and division of natural units of the sea areas but also creates a basis for the orientation of natural resource management resources, environmental protection, and conservation of marine-island biodiversity. The principles of marine-island landscape mapping are to define terminology and establish a classification system based on taxonomy and criteria. This article represents the establishment of marine-island landscape mapping of Nam Yet Island and adjacent water (scaled at 1:10000) through comprehensive work, including marine-island landscape classification, applied GIS - remote sensing, and field investigation in the two years of 2020-2021. Accordingly, the landscape classification system of the Nam Yet Island area includes 1 system, 1 subsystem, 4 classes, 6 subclasses, 10 types, 29 kinds, and 34 forms of landscape (of which 4 island forms and 30 marine forms). The units of the marine-island landscape fully express the natural components, anthropogenic factors, and biotic and abiotic factors in their relationship and interaction with each other. Depending on each corresponding level, the detailed level of components and landscape elements is shown, in which components and biological factors are studied and analyzed most fully. The research results have clarified the characteristics and the law of differentiation of the marine-island landscape in Nam Yet Island, contributing to supplementing knowledge about Truong Sa Islands of Vietnam, which is a scientific basis for resource management and biodiversity conservation, protecting the marine environment, and at the same time supplementing the theoretical basis for the study of the tropical monsoon tropical island and marine landscape, which has not yet been studied in Vietnam.
{"title":"Classification and mapping of marine-island landscape in Nam Yet Island, Truong Sa Islands, Vietnam","authors":"Hoi Nguyen Dang, Dung Ngo Trung, A. Kuznetsov, Phuong Vu Le","doi":"10.15625/2615-9783/17178","DOIUrl":"https://doi.org/10.15625/2615-9783/17178","url":null,"abstract":"Classification and mapping of marine-island landscapes according to an integrated approach not only clarifies the structure and division of natural units of the sea areas but also creates a basis for the orientation of natural resource management resources, environmental protection, and conservation of marine-island biodiversity. The principles of marine-island landscape mapping are to define terminology and establish a classification system based on taxonomy and criteria. This article represents the establishment of marine-island landscape mapping of Nam Yet Island and adjacent water (scaled at 1:10000) through comprehensive work, including marine-island landscape classification, applied GIS - remote sensing, and field investigation in the two years of 2020-2021. Accordingly, the landscape classification system of the Nam Yet Island area includes 1 system, 1 subsystem, 4 classes, 6 subclasses, 10 types, 29 kinds, and 34 forms of landscape (of which 4 island forms and 30 marine forms). The units of the marine-island landscape fully express the natural components, anthropogenic factors, and biotic and abiotic factors in their relationship and interaction with each other. Depending on each corresponding level, the detailed level of components and landscape elements is shown, in which components and biological factors are studied and analyzed most fully. The research results have clarified the characteristics and the law of differentiation of the marine-island landscape in Nam Yet Island, contributing to supplementing knowledge about Truong Sa Islands of Vietnam, which is a scientific basis for resource management and biodiversity conservation, protecting the marine environment, and at the same time supplementing the theoretical basis for the study of the tropical monsoon tropical island and marine landscape, which has not yet been studied in Vietnam.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47490148","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-28DOI: 10.15625/2615-9783/17177
Binh Thai Pham, Dam Duc Nguyen, Quynh-Anh Bui Thi, Manh Duc Nguyen, Thanh Tien Vu, Indra Prakash
The ultimate bearing capacity of bored piles is an essential parameter in foundation design of structure. In the present study, three Machine Learning (ML) methods namely Adaptive Neuro-Fuzzy Inference System (ANFIS), Support Vector Machine (SVM) and Artificial Neural Network (ANN) were utilized to estimate bearing capacity of bored piles based on limited engineering parameters of pile and soil obtained from 75 test sites in Vietnam. These parameters include pile diameter, pile length, tensile strength of main longitudinal steel bar, compressive strength of concrete, average SPT index at the tip of the pile, average SPT index at the pile body. Validation of the methods was verified using standard statistical metrics namely Root Mean Square Error (RMSE) and Correlation coefficient (R). The results show that all the proposed models have good potential in predicting correctly bearing capacity of bored piles on training data (R>0.93) and on testing data (R>0.88) but performance of the SVM model is the best (R:0.985 (training) and R:0.958 (testing). Thus SVM model can be used for the accurate prediction of ultimate bearing capacity of bored piles for proper designing of the civil engineering structure foundation.
{"title":"Estimation of ultimate bearing capacity of bored piles using machine learning models","authors":"Binh Thai Pham, Dam Duc Nguyen, Quynh-Anh Bui Thi, Manh Duc Nguyen, Thanh Tien Vu, Indra Prakash","doi":"10.15625/2615-9783/17177","DOIUrl":"https://doi.org/10.15625/2615-9783/17177","url":null,"abstract":"The ultimate bearing capacity of bored piles is an essential parameter in foundation design of structure. In the present study, three Machine Learning (ML) methods namely Adaptive Neuro-Fuzzy Inference System (ANFIS), Support Vector Machine (SVM) and Artificial Neural Network (ANN) were utilized to estimate bearing capacity of bored piles based on limited engineering parameters of pile and soil obtained from 75 test sites in Vietnam. These parameters include pile diameter, pile length, tensile strength of main longitudinal steel bar, compressive strength of concrete, average SPT index at the tip of the pile, average SPT index at the pile body. Validation of the methods was verified using standard statistical metrics namely Root Mean Square Error (RMSE) and Correlation coefficient (R). The results show that all the proposed models have good potential in predicting correctly bearing capacity of bored piles on training data (R>0.93) and on testing data (R>0.88) but performance of the SVM model is the best (R:0.985 (training) and R:0.958 (testing). Thus SVM model can be used for the accurate prediction of ultimate bearing capacity of bored piles for proper designing of the civil engineering structure foundation.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-05-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45344891","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-05-11DOI: 10.15625/2615-9783/17118
Ngoc Hoang Thi Huyen, Ha Nguyen Manh, Dung Bui Quang
In the quest for poverty reduction, developing sustainable agriculture and stabilizing cultivation areas for specialty plants can be substantially improved by a new approach, which combines land suitability assessment and designs of ecological-economic models. The land suitability was assessed according to the FAO framework and the Vietnamese standard TCVN-8409:2012. The criteria were grouped in the parameters of climate, topography, and soil physicochemical properties. The seven land utilization types selected for analysis included orange, banana, tea, turmeric, cinnamon, chinaberry, and chukrasia in mountainous regions of Thanh Hoa and Nghe An Provinces, Vietnam. The results showed that the most suitable lands (S1) for cultivating these crops were 169.916 ha for orange, 201.166 ha for banana, 107.636 ha for tea, and 570.744 ha for turmeric, 233.987 ha for cinnamon, 633.306 ha for chinaberry, and 280.704 ha for chukrasia. Based on that foundation, the study designed three ecological models with economic efficiency and elaborated on six formations of the models. The analyses obtained from the research also allowed the proposal of six prioritized spaces for land use and environmental protection, which were illustrated on a 1:100,000 map of proposed agricultural land use. Therefore, this study provided a detailed and reliable approach for researchers and managers in agricultural land use planning. A proper procedure for the assessment of agricultural land in mountainous areas can be suggested from this research.
{"title":"A combined approach for sustainable use of mountainous agricultural land: land suitability evaluation and ecological-economic model","authors":"Ngoc Hoang Thi Huyen, Ha Nguyen Manh, Dung Bui Quang","doi":"10.15625/2615-9783/17118","DOIUrl":"https://doi.org/10.15625/2615-9783/17118","url":null,"abstract":"In the quest for poverty reduction, developing sustainable agriculture and stabilizing cultivation areas for specialty plants can be substantially improved by a new approach, which combines land suitability assessment and designs of ecological-economic models. The land suitability was assessed according to the FAO framework and the Vietnamese standard TCVN-8409:2012. The criteria were grouped in the parameters of climate, topography, and soil physicochemical properties. The seven land utilization types selected for analysis included orange, banana, tea, turmeric, cinnamon, chinaberry, and chukrasia in mountainous regions of Thanh Hoa and Nghe An Provinces, Vietnam. The results showed that the most suitable lands (S1) for cultivating these crops were 169.916 ha for orange, 201.166 ha for banana, 107.636 ha for tea, and 570.744 ha for turmeric, 233.987 ha for cinnamon, 633.306 ha for chinaberry, and 280.704 ha for chukrasia. Based on that foundation, the study designed three ecological models with economic efficiency and elaborated on six formations of the models. The analyses obtained from the research also allowed the proposal of six prioritized spaces for land use and environmental protection, which were illustrated on a 1:100,000 map of proposed agricultural land use. Therefore, this study provided a detailed and reliable approach for researchers and managers in agricultural land use planning. A proper procedure for the assessment of agricultural land in mountainous areas can be suggested from this research.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-05-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43990330","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-04-21DOI: 10.15625/2615-9783/17081
Luu Tran Thi, Hiền Nguyễn Thị Thu
Groundwater over-exploitation in the south of Hanoi has formed depression cones and accelerated land subsidence. Thanh Xuan district is one of the most suffered areas in the south of Hanoi. Artificial groundwater recharge (AGR) is an effective solution to mitigate those negative impacts. This study aims to evaluate the potential of rooftop rainwater harvesting (RRH) for AGR in the Thanh Xuan district. The prospect of RRH for the study area is estimated based on the average annual rainfall for the period 2008-2018 and the total rooftop area of selected buildings. The rooftop area is determined by analyzing satellite images and using the built-in tool in Google Earth. Field site investigation and measurements confirmed this estimation. Rainwater samples were taken for quality assessment. This assessment was conducted by measuring pH, EC, TDS, turbidity of rainwater in the field and analyzing NO3-, NO2-, PO43-, SO42- and Cl- contents in the laboratory. Moreover, to propose an effective AGR system, the maximum harvested rainwater and the recharge capacity of an injection well were estimated for the Golden Land building. The results show that 397 selected buildings can be used to collect rainwater. The total rooftop area of these 397 buildings is 262,645.8 m2, and that can contain 385,930.5 m3 of rainwater a year. The field measurement and analysis results indicate that rainwater quality meets the current standards appropriate for AGR. The AGR using rooftop rainwater will contribute to increasing groundwater level, reducing land subsidence, and mitigating urban flooding for Thanh Xuan and similar areas.
{"title":"Rooftop rainwater harvesting and artificial roundwater recharge - a case study: Thanh Xuan district in south of Hanoi","authors":"Luu Tran Thi, Hiền Nguyễn Thị Thu","doi":"10.15625/2615-9783/17081","DOIUrl":"https://doi.org/10.15625/2615-9783/17081","url":null,"abstract":"Groundwater over-exploitation in the south of Hanoi has formed depression cones and accelerated land subsidence. Thanh Xuan district is one of the most suffered areas in the south of Hanoi. Artificial groundwater recharge (AGR) is an effective solution to mitigate those negative impacts. This study aims to evaluate the potential of rooftop rainwater harvesting (RRH) for AGR in the Thanh Xuan district. The prospect of RRH for the study area is estimated based on the average annual rainfall for the period 2008-2018 and the total rooftop area of selected buildings. The rooftop area is determined by analyzing satellite images and using the built-in tool in Google Earth. Field site investigation and measurements confirmed this estimation. Rainwater samples were taken for quality assessment. This assessment was conducted by measuring pH, EC, TDS, turbidity of rainwater in the field and analyzing NO3-, NO2-, PO43-, SO42- and Cl- contents in the laboratory. Moreover, to propose an effective AGR system, the maximum harvested rainwater and the recharge capacity of an injection well were estimated for the Golden Land building. The results show that 397 selected buildings can be used to collect rainwater. The total rooftop area of these 397 buildings is 262,645.8 m2, and that can contain 385,930.5 m3 of rainwater a year. The field measurement and analysis results indicate that rainwater quality meets the current standards appropriate for AGR. The AGR using rooftop rainwater will contribute to increasing groundwater level, reducing land subsidence, and mitigating urban flooding for Thanh Xuan and similar areas.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-04-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47407147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-22DOI: 10.15625/2615-9783/17013
Luan Pham Thanh, E. Oksum, O. Kafadar, Trinh Phan Trong, Dat Nguyen Viet, Quynh Vo Thanh, Sang Le Thi
The Hoang Sa islands, located in the northern part of the East Vietnam Sea, lack information on geological structural boundaries. The gravity data from the global marine gravity model were analyzed using the enhanced total horizontal gradient methods to delineate geological structures that appear as lineaments on the transformed gravity anomaly maps of the area. Before applying the techniques to gravity data of the Hoang Sa islands, their effectiveness was demonstrated by comparing them with the results from the total horizontal gradient method for a synthetic model. Applying the enhanced horizontal gradient methods shows that most of the lineaments identified in the Hoang Sa islands are trending in the WSW-ENE, NE-SW, E-W, WNW-ESE and NNW-SSE directions. These results provide a better understanding of the subsurface structural features of the islands.
{"title":"Determination of subsurface lineaments in the Hoang Sa islands using enhanced methods of gravity total horizontal gradient","authors":"Luan Pham Thanh, E. Oksum, O. Kafadar, Trinh Phan Trong, Dat Nguyen Viet, Quynh Vo Thanh, Sang Le Thi","doi":"10.15625/2615-9783/17013","DOIUrl":"https://doi.org/10.15625/2615-9783/17013","url":null,"abstract":"The Hoang Sa islands, located in the northern part of the East Vietnam Sea, lack information on geological structural boundaries. The gravity data from the global marine gravity model were analyzed using the enhanced total horizontal gradient methods to delineate geological structures that appear as lineaments on the transformed gravity anomaly maps of the area. Before applying the techniques to gravity data of the Hoang Sa islands, their effectiveness was demonstrated by comparing them with the results from the total horizontal gradient method for a synthetic model. Applying the enhanced horizontal gradient methods shows that most of the lineaments identified in the Hoang Sa islands are trending in the WSW-ENE, NE-SW, E-W, WNW-ESE and NNW-SSE directions. These results provide a better understanding of the subsurface structural features of the islands.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46881456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-22DOI: 10.15625/2615-9783/17010
Pankaj Kumar, Bhavesh Pandey, Kamal, Ashok Kumar
Site classification is vital to carry out seismic hazard analysis of a region and get the damage patterns caused by earthquakes. In the present study, the ground motion of earthquakes recorded from 2015 to 2019 at 84 sites of the seismic network array of Earthquake Early Warning System for Uttarakhand are analyzed for site classification purposes. The predominant period from the mean horizontal to vertical spectral ratio curves was estimated. The classification schemes devised by Japan Road Association and National Earthquake Hazards Reduction Program are applied to classify the sites. Along with this, two other site classification indexes schemes are also applied for classification purposes. Data winnowing techniques are used over the ground motion records to pick out desirable quality records. Conclusively, the site class with the highest recurrence rate amongst the used methods is selected as the final class for that particular site. The effect of magnitude, distance and depth on horizontal to vertical spectral ratio are described and concluded that these factors do not significantly affect the ratio curves. The average horizontal to vertical spectral ratio curves obtained for all the sites matches well with the existing literature. The classification of a few sites are verified from the classification done by other methods in recent studies. It is evident from the results that the classification done in this study matches well with them.
{"title":"Site classification of seismic recording stations of Garhwal region of earthquake early warning system for Uttarakhand, India","authors":"Pankaj Kumar, Bhavesh Pandey, Kamal, Ashok Kumar","doi":"10.15625/2615-9783/17010","DOIUrl":"https://doi.org/10.15625/2615-9783/17010","url":null,"abstract":"Site classification is vital to carry out seismic hazard analysis of a region and get the damage patterns caused by earthquakes. In the present study, the ground motion of earthquakes recorded from 2015 to 2019 at 84 sites of the seismic network array of Earthquake Early Warning System for Uttarakhand are analyzed for site classification purposes. The predominant period from the mean horizontal to vertical spectral ratio curves was estimated. The classification schemes devised by Japan Road Association and National Earthquake Hazards Reduction Program are applied to classify the sites. Along with this, two other site classification indexes schemes are also applied for classification purposes. Data winnowing techniques are used over the ground motion records to pick out desirable quality records. Conclusively, the site class with the highest recurrence rate amongst the used methods is selected as the final class for that particular site. The effect of magnitude, distance and depth on horizontal to vertical spectral ratio are described and concluded that these factors do not significantly affect the ratio curves. The average horizontal to vertical spectral ratio curves obtained for all the sites matches well with the existing literature. The classification of a few sites are verified from the classification done by other methods in recent studies. It is evident from the results that the classification done in this study matches well with them.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46399954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-17DOI: 10.15625/2615-9783/17002
Anh Tran Tuan, Hoa Tran Trong, Can Pham Ngoc, Gregory Shellnutt J., Thuy Pham T., Andrey Izokh E., Lien Pham Thi Phuong
Granitoids from seven massifs in northwest Vietnam, including I-type granites (Nam Meng, Nam Rom, and Song Ma massifs) and S-type granites (Pu Si Lung, Kim Boi, Muong Lat, and Sam Son massifs) that distributed along the Dien Bien-Song Ma fault at the northern part of Truong Son Fold Belt, were studied to understand the mineralogy, whole-rock geochemistry, Nd-Sr isotopes, and U-Pb zircon geochronology. The I-type granitoid rocks vary from gabbro diorite to diorite and granodiorite to granite (SiO2 = 52.4 - 71.1 wt.%) and from calc-alkaline to high K calc-alkaline to shoshonite (Nam Rom massif) series. Biotite in the I-type granitoid rocks has high Mg, intermediate to high Ti, and low Al (Phl-0.43 - Sid-0.29 - Ann-0.28); amphibole is edenite (Nam Rom massif) and ferro-edenite (Song Ma massif). The ASI varies from 0.64 to 1.14 (metaluminous); K/Na = 0.1-0.7; ratios of K/Rb, Rb/Sr and Rb/Ba varies from 179-334, 0.40-3.50, and 0.16-0.38; [La/Sm]N, [La/Yb]N and [Gd/Yb]N are varies within 1.08-4.92, 1.57-27.3, and 1.07-3.72, respectively. Their 87Sr/86Sr and ƐNd(t) are highly enriched, respectively, from 0.7072 to 0.7319 and -12.2 to -6.67. The I-type granitoid rocks may be mixtures between mantle-derived and crustal components based on geochemical characteristics. In contrast, the Nam Meng magma was mantle-dominated, and the Nam Rom and Song Ma magmas were crustal-dominated. The S-type granitoid rocks include biotite granite and two-mica granite (SiO2 = 68.9-73.0 wt.%), varying from high K calc-alkaline to shoshonite series. The S-type granitoid rocks are distinct from the I-type granitoid rocks by sillimanite, cordierite, and muscovite. Biotite in the S-type granitoid rocks has high Ti and Al and low Mg. The mineral was partially replaced by muscovite. The ASI varies from 1.1 to 1.85 (peraluminous); K/Rb, Rb/Sr, and Rb/Ba vary within 161-188, 0.37-3.50, and 0.15-0.98; [La/Sm]N, [La/Yb]N and [Gd/Yb]N vary within 2.28-3.90, 5.93-16.8, and 1.72-2.93, respectively. The S-type granitoid rocks also have high 87Sr/86Sr(i) (0.7227-0.7335) and low ƐNd(t) (-12.4 to -9.8) with TDM = 2.11-2.71 billion years, indicating a mature crust protolith. The in situ zircon U-Pb ages of the I-type granites are 289-296 Ma (Nam Meng massif) and 245-225 Ma (Nam Rom and Song Ma massifs), while those of the S-type granitoid rocks (Kim Boi and Muong Lat massifs) are 242-235 Ma. The above data suggest that the Indochina and Sino-Vietnam composite terranes produced the Permian-Triassic granitoid rocks in northwest Vietnam. The convergence had led to subduction activity forming Nam Meng granitoid, syn-collision activity forming Kim Boi, Muong Lat, and Sam Son massifs, and ended with post-collision activity forming Nam Rom and Song Ma massifs.
{"title":"Petrology of the Permian-Triassic granitoids in Northwest Vietnam and their relation to the amalgamation of the Indochina and Sino-Vietnam composite terranes","authors":"Anh Tran Tuan, Hoa Tran Trong, Can Pham Ngoc, Gregory Shellnutt J., Thuy Pham T., Andrey Izokh E., Lien Pham Thi Phuong","doi":"10.15625/2615-9783/17002","DOIUrl":"https://doi.org/10.15625/2615-9783/17002","url":null,"abstract":"Granitoids from seven massifs in northwest Vietnam, including I-type granites (Nam Meng, Nam Rom, and Song Ma massifs) and S-type granites (Pu Si Lung, Kim Boi, Muong Lat, and Sam Son massifs) that distributed along the Dien Bien-Song Ma fault at the northern part of Truong Son Fold Belt, were studied to understand the mineralogy, whole-rock geochemistry, Nd-Sr isotopes, and U-Pb zircon geochronology. The I-type granitoid rocks vary from gabbro diorite to diorite and granodiorite to granite (SiO2 = 52.4 - 71.1 wt.%) and from calc-alkaline to high K calc-alkaline to shoshonite (Nam Rom massif) series. Biotite in the I-type granitoid rocks has high Mg, intermediate to high Ti, and low Al (Phl-0.43 - Sid-0.29 - Ann-0.28); amphibole is edenite (Nam Rom massif) and ferro-edenite (Song Ma massif). The ASI varies from 0.64 to 1.14 (metaluminous); K/Na = 0.1-0.7; ratios of K/Rb, Rb/Sr and Rb/Ba varies from 179-334, 0.40-3.50, and 0.16-0.38; [La/Sm]N, [La/Yb]N and [Gd/Yb]N are varies within 1.08-4.92, 1.57-27.3, and 1.07-3.72, respectively. Their 87Sr/86Sr and ƐNd(t) are highly enriched, respectively, from 0.7072 to 0.7319 and -12.2 to -6.67. The I-type granitoid rocks may be mixtures between mantle-derived and crustal components based on geochemical characteristics. In contrast, the Nam Meng magma was mantle-dominated, and the Nam Rom and Song Ma magmas were crustal-dominated. The S-type granitoid rocks include biotite granite and two-mica granite (SiO2 = 68.9-73.0 wt.%), varying from high K calc-alkaline to shoshonite series. The S-type granitoid rocks are distinct from the I-type granitoid rocks by sillimanite, cordierite, and muscovite. Biotite in the S-type granitoid rocks has high Ti and Al and low Mg. The mineral was partially replaced by muscovite. The ASI varies from 1.1 to 1.85 (peraluminous); K/Rb, Rb/Sr, and Rb/Ba vary within 161-188, 0.37-3.50, and 0.15-0.98; [La/Sm]N, [La/Yb]N and [Gd/Yb]N vary within 2.28-3.90, 5.93-16.8, and 1.72-2.93, respectively. The S-type granitoid rocks also have high 87Sr/86Sr(i) (0.7227-0.7335) and low ƐNd(t) (-12.4 to -9.8) with TDM = 2.11-2.71 billion years, indicating a mature crust protolith. The in situ zircon U-Pb ages of the I-type granites are 289-296 Ma (Nam Meng massif) and 245-225 Ma (Nam Rom and Song Ma massifs), while those of the S-type granitoid rocks (Kim Boi and Muong Lat massifs) are 242-235 Ma. The above data suggest that the Indochina and Sino-Vietnam composite terranes produced the Permian-Triassic granitoid rocks in northwest Vietnam. The convergence had led to subduction activity forming Nam Meng granitoid, syn-collision activity forming Kim Boi, Muong Lat, and Sam Son massifs, and ended with post-collision activity forming Nam Rom and Song Ma massifs.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48628626","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-15DOI: 10.15625/2615-9783/16998
Huyen Bui Thuong, Thu Le Phuong, Phuong Nguyen Thu, Duy Le Ngoc, Linh Vo Dieu, Anh Pham Le, Luong Nguyen Lam, Hue Nguyen Thi, Tuan Le Vinh, H. Mai, Thanh Dinh Thi Mai, M. Herrmann, S. Ouillon, Thuy Duong Thi, Q. Le Thi Phuong
In this research, rice husk-derived biochar (BC) was evaluated to determine the suitable conditions for the methylene blue (MB) solution adsorption. The characterization of BC was identified by the methods of FT-IR, Raman, and point of zero charges (PZC). The adsorption studies were carried out with BC at different activation conditions (raw BC, HNO3 25% for 4 hours, NaOH 25% for 4 hours, H2O at 90°C for 2 hours and 4 hours, HNO3 25% at 90°C for 2 hours and 4 hours). The activated material then went through an adsorption assessment. Activated BC with NaOH 25% showed its preeminence compared to the other six conditions when reaching the maximum efficiency after the first hour of adsorption. The investigation revealed that the adsorption capacity of the material depends on the activation methods, including pH, activation agent, temperature, and time. The adsorption of BC was consistent with the pseudo-first-order kinetic model and the Langmuir isotherm model, with high correlation coefficients (R2: 0.9838 and 0.9975, respectively). Therefore, it can be concluded that the use of rice husk is feasible for the removal of MB from aqueous solutions.
{"title":"Removal of methylene blue from aqueous solution by biochar derived from rice husk","authors":"Huyen Bui Thuong, Thu Le Phuong, Phuong Nguyen Thu, Duy Le Ngoc, Linh Vo Dieu, Anh Pham Le, Luong Nguyen Lam, Hue Nguyen Thi, Tuan Le Vinh, H. Mai, Thanh Dinh Thi Mai, M. Herrmann, S. Ouillon, Thuy Duong Thi, Q. Le Thi Phuong","doi":"10.15625/2615-9783/16998","DOIUrl":"https://doi.org/10.15625/2615-9783/16998","url":null,"abstract":"In this research, rice husk-derived biochar (BC) was evaluated to determine the suitable conditions for the methylene blue (MB) solution adsorption. The characterization of BC was identified by the methods of FT-IR, Raman, and point of zero charges (PZC). The adsorption studies were carried out with BC at different activation conditions (raw BC, HNO3 25% for 4 hours, NaOH 25% for 4 hours, H2O at 90°C for 2 hours and 4 hours, HNO3 25% at 90°C for 2 hours and 4 hours). The activated material then went through an adsorption assessment. Activated BC with NaOH 25% showed its preeminence compared to the other six conditions when reaching the maximum efficiency after the first hour of adsorption. The investigation revealed that the adsorption capacity of the material depends on the activation methods, including pH, activation agent, temperature, and time. The adsorption of BC was consistent with the pseudo-first-order kinetic model and the Langmuir isotherm model, with high correlation coefficients (R2: 0.9838 and 0.9975, respectively). Therefore, it can be concluded that the use of rice husk is feasible for the removal of MB from aqueous solutions.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2022-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42319628","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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