Pub Date : 2023-08-10DOI: 10.15625/2615-9783/18644
Huu Duy Nguyen, Dinh Kha Dang, Y. Nhu Nguyen, Chien Pham Van, Quang- Hai Truong, Quang- Thanh Bui, Alexandru- Ionut Petrisor
Flood models based on traditional hydrodynamic modeling encounter significant difficulties with real-time predictions, require enormous computational resources, and perform poorly in data-limited regions. The difficulties are compounded as flooding worldwide worsens due to the increasing frequency of short-term torrential rain events, making it more challenging to predict floods over the long term. This study aims to address these challenges by developing a rapid flood forecasting model combining machine learning algorithms (support vector regression, XGBoost regression, CatBoost regression, and decision tree regression) with hydrodynamic modeling in Quang Tri province in Vietnam. 560 flood depth locations were obtained by hydrodynamic modeling, and several locations measured in the field were used as input data for the machine learning models to build a flood depth map for the study area. The statistical indices used to evaluate the performance of the four proposed models were the receiver operating characteristic (ROC) curve, area under the ROC curve, root mean square error, mean absolute error, and coefficient of determination (R2). The results showed that all four models successfully constructed a flood depth map for the study area. Among the four proposed models, CatBoost regression performed best, with an R² value of 0.86. This was followed by XGBoost regression (R²=0.84), decision tree regression (R²=0.72), and then support vector regression (R2=0.7). This integration of hydrodynamic modeling and machine learning complements the framework in much of the existing literature. It can provide decision-makers and local authorities with an advanced flood warning tool and contribute to improving sustainable development strategies in this and similar regions.
{"title":"A framework for flood depth using hydrodynamic modeling and machine learning in the coastal province of Vietnam","authors":"Huu Duy Nguyen, Dinh Kha Dang, Y. Nhu Nguyen, Chien Pham Van, Quang- Hai Truong, Quang- Thanh Bui, Alexandru- Ionut Petrisor","doi":"10.15625/2615-9783/18644","DOIUrl":"https://doi.org/10.15625/2615-9783/18644","url":null,"abstract":"Flood models based on traditional hydrodynamic modeling encounter significant difficulties with real-time predictions, require enormous computational resources, and perform poorly in data-limited regions. The difficulties are compounded as flooding worldwide worsens due to the increasing frequency of short-term torrential rain events, making it more challenging to predict floods over the long term. This study aims to address these challenges by developing a rapid flood forecasting model combining machine learning algorithms (support vector regression, XGBoost regression, CatBoost regression, and decision tree regression) with hydrodynamic modeling in Quang Tri province in Vietnam. 560 flood depth locations were obtained by hydrodynamic modeling, and several locations measured in the field were used as input data for the machine learning models to build a flood depth map for the study area. The statistical indices used to evaluate the performance of the four proposed models were the receiver operating characteristic (ROC) curve, area under the ROC curve, root mean square error, mean absolute error, and coefficient of determination (R2). The results showed that all four models successfully constructed a flood depth map for the study area. Among the four proposed models, CatBoost regression performed best, with an R² value of 0.86. This was followed by XGBoost regression (R²=0.84), decision tree regression (R²=0.72), and then support vector regression (R2=0.7). This integration of hydrodynamic modeling and machine learning complements the framework in much of the existing literature. It can provide decision-makers and local authorities with an advanced flood warning tool and contribute to improving sustainable development strategies in this and similar regions.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42117485","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 : 2023-08-04DOI: 10.15625/2615-9783/18616
Thi Oanh Doan, Thi Thuy Duong, Thi Khoa My Nguyen, Thi Quynh Hoang, Thanh Tam Luong, Phuong Thao Pham, Thi Thanh Nga Cao, Phuong Thu Le, Hieu Phung Hieu Phung, Thi Phuong Quynh Le, Thi Mai Anh Dang, Phuong Thuy Bui, Thanh Nghi Duong, Van Cuong Bui
Microplastics (MPs) have been extensively studied in aquatic systems; however, their presence in general agricultural systems and in particular, soil still needs comprehensive understanding. This study conducted a field survey at 25 sites to investigate the abundance of MPs in agricultural soil. The MPs in these soil samples were separated using sieves and filters by the density separation method with NaCl solution (d = 1.2 g/cm3). The density of MPs in agricultural soils ranged from 1,700 items/kg to 38,800 items/kg, with an average of 11,716 ±10,726 items/kg. The black-colored MPs were found to be dominant, followed by white, purple, red, and blue. The fibers represented most of the MPs' shapes observed in this research (77.9±17.4%). MPs in agricultural soil samples were tiny particles with sizes of <1,000 µm and 1,000-2,000 µm. A significant difference was observed in the concentration of MPs in locations near and far from residential areas and manufacturing facilities. The average concentration of MPs in the soils adjacent to the residential and manufacturing facilities and near the agricultural solid waste collection sites was 21,471±12,729 items/kg and 20,188±4,403 items/kg, much higher than in distant these locations at 4,418±1,573 items/kg. These results suggest that domestic, industrial, and agricultural activities could contribute to MP pollution in agricultural soil. The ecological dangers MPs pose in terrestrial and aquatic environments have drawn much attention from the scientific community. This work represented the first effort to comprehend the ecological risk of MPs on selected samples of Vietnamese agricultural soil. According to the Pollution Load Index (PLI) values, most agricultural soil samples in this study were contaminated with MPs at hazard level IV. The potential ecological risk index (PERI) values of agricultural soil samples from nearby residential, industrial, or agricultural solid waste areas indicated a higher ecological risk.
{"title":"Preliminary results on microplastic pollution from agricultural soil in Vietnam: Distribution, characterization, and ecological risk assessment","authors":"Thi Oanh Doan, Thi Thuy Duong, Thi Khoa My Nguyen, Thi Quynh Hoang, Thanh Tam Luong, Phuong Thao Pham, Thi Thanh Nga Cao, Phuong Thu Le, Hieu Phung Hieu Phung, Thi Phuong Quynh Le, Thi Mai Anh Dang, Phuong Thuy Bui, Thanh Nghi Duong, Van Cuong Bui","doi":"10.15625/2615-9783/18616","DOIUrl":"https://doi.org/10.15625/2615-9783/18616","url":null,"abstract":"Microplastics (MPs) have been extensively studied in aquatic systems; however, their presence in general agricultural systems and in particular, soil still needs comprehensive understanding. This study conducted a field survey at 25 sites to investigate the abundance of MPs in agricultural soil. The MPs in these soil samples were separated using sieves and filters by the density separation method with NaCl solution (d = 1.2 g/cm3). The density of MPs in agricultural soils ranged from 1,700 items/kg to 38,800 items/kg, with an average of 11,716 ±10,726 items/kg. The black-colored MPs were found to be dominant, followed by white, purple, red, and blue. The fibers represented most of the MPs' shapes observed in this research (77.9±17.4%). MPs in agricultural soil samples were tiny particles with sizes of <1,000 µm and 1,000-2,000 µm. A significant difference was observed in the concentration of MPs in locations near and far from residential areas and manufacturing facilities. The average concentration of MPs in the soils adjacent to the residential and manufacturing facilities and near the agricultural solid waste collection sites was 21,471±12,729 items/kg and 20,188±4,403 items/kg, much higher than in distant these locations at 4,418±1,573 items/kg. These results suggest that domestic, industrial, and agricultural activities could contribute to MP pollution in agricultural soil. The ecological dangers MPs pose in terrestrial and aquatic environments have drawn much attention from the scientific community. This work represented the first effort to comprehend the ecological risk of MPs on selected samples of Vietnamese agricultural soil. According to the Pollution Load Index (PLI) values, most agricultural soil samples in this study were contaminated with MPs at hazard level IV. The potential ecological risk index (PERI) values of agricultural soil samples from nearby residential, industrial, or agricultural solid waste areas indicated a higher ecological risk.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42818564","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 : 2023-08-04DOI: 10.15625/2615-9783/18620
Nguyen Nhu Trung, Bui Viet Dung, Bui Van Nam, Pham Nguyen Ha Vu, Nguyen Van Kieu
This study investigates the stratigraphic architectures of the South Vietnam continental margin (SVCM) from the Pliocene to the recent period. We have utilized high-resolution seismic data and sediment core data to achieve this. The study reveals that the Quaternary sequences on the continental margin are bounded by composite erosional surfaces, which were formed due to sub-aerial erosion during periods of sea level fall and subsequent reworking processes during sea level rise. The Quaternary sequence can be divided into two subsequences: the Early Pleistocene and the Middle Pleistocene-Holocene. The Middle Pleistocene-Holocene sequences can be subdivided into six fourth-order sequences, each lasting approximately 100 to 120 thousand years. These sequences are well-preserved on the outer shelf at a modern water depth of around 100 to 120 meters. Seismic stacking patterns indicate that regressive deposits predominantly dominate the Quaternary stratigraphy of the SVCM. This means that sediment deposition during the Quaternary period was more pronounced during periods of sea-level fall. The outer shelf margin of the modern continental margin shows a south-to-southeastward migration of prograding clinoforms, indicating sediment progradation in these directions. The thick Quaternary regressive deposits preserved on the outer shelf are attributed to various factors. These factors include the low shelf gradient, tectonic subsidence, regional hinterland uplift, monsoon strengthening, and high sediment supply from the Palaeo-Mekong Delta during sea-level fall. The interaction of these factors facilitated the accumulation of thick sedimentary deposits during falling sea levels. The mid-late Pleistocene stratigraphy of the SVCM shows similarities to many other continental margins worldwide. These margins are mainly shaped under the influence of asymmetric 4th-order Milankovitch cycles. These cycles are driven by variations in Earth's orbital parameters and are characterized by longer phases of relative sea-level fall followed by shorter periods of stabilization and rise.
{"title":"Quaternary stratigraphy of southern Vietnam continental margin","authors":"Nguyen Nhu Trung, Bui Viet Dung, Bui Van Nam, Pham Nguyen Ha Vu, Nguyen Van Kieu","doi":"10.15625/2615-9783/18620","DOIUrl":"https://doi.org/10.15625/2615-9783/18620","url":null,"abstract":"This study investigates the stratigraphic architectures of the South Vietnam continental margin (SVCM) from the Pliocene to the recent period. We have utilized high-resolution seismic data and sediment core data to achieve this. The study reveals that the Quaternary sequences on the continental margin are bounded by composite erosional surfaces, which were formed due to sub-aerial erosion during periods of sea level fall and subsequent reworking processes during sea level rise. The Quaternary sequence can be divided into two subsequences: the Early Pleistocene and the Middle Pleistocene-Holocene. The Middle Pleistocene-Holocene sequences can be subdivided into six fourth-order sequences, each lasting approximately 100 to 120 thousand years. These sequences are well-preserved on the outer shelf at a modern water depth of around 100 to 120 meters. Seismic stacking patterns indicate that regressive deposits predominantly dominate the Quaternary stratigraphy of the SVCM. This means that sediment deposition during the Quaternary period was more pronounced during periods of sea-level fall. The outer shelf margin of the modern continental margin shows a south-to-southeastward migration of prograding clinoforms, indicating sediment progradation in these directions. The thick Quaternary regressive deposits preserved on the outer shelf are attributed to various factors. These factors include the low shelf gradient, tectonic subsidence, regional hinterland uplift, monsoon strengthening, and high sediment supply from the Palaeo-Mekong Delta during sea-level fall. The interaction of these factors facilitated the accumulation of thick sedimentary deposits during falling sea levels. The mid-late Pleistocene stratigraphy of the SVCM shows similarities to many other continental margins worldwide. These margins are mainly shaped under the influence of asymmetric 4th-order Milankovitch cycles. These cycles are driven by variations in Earth's orbital parameters and are characterized by longer phases of relative sea-level fall followed by shorter periods of stabilization and rise.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48273201","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 : 2023-08-01DOI: 10.15625/2615-9783/18595
H. Mai, Van Hoi Bui, Thanh Duong Dao, Thanh Duong Nguyen, Danh Thien Nguyen, Toan Khanh Vu, Nguyen Hoang Anh Chu, Manh Quan Tran, Emillie Stragy
Microplastics are nowadays considered ubiquitous pollutants since they have been found widespread in all environmental compartments, particularly in aquatic systems. In urban water bodies, municipal wastewater discharges and overflows of combined storm and wastewater drains are the sources of microplastic pollution. The investigation was performed on the distribution of microplastics in the surface water of three urban lakes: West Lake, Yen So Lake, and Bay Mau Lake, from February 2020 to January 2021. Results show that microplastics were widely and unevenly distributed in all three lakes in Ha Noi and reached a high abundance on the site of West Lake, which is most intensively surrounded by population density, restaurants/bars, and aquaculture activities. Microplastic abundance was highest in February 2020 for all three urban lakes, with 154.92 items m-3 in Bay Mau, 589.46 items m-3 in West Lake, and 139.86 items m-3 in Yen So Lake. There was a decreasing trend in the following sampling times of July, October 2020, and January 2021 (range: Bay Mau: 16.02-59.04 items m-3; West Lake: 36.51-201.08 items m-3; Yen So: 14.07-67.27 items m-3). The dominant microplastics in urban lakes were fibers with a size of 1-3 mm, while microplastic fragments were 0.045-0.3 mm2. Analysis of the chemical composition of microplastics indicated dominance by rayon (13.5-58.5%) and polyethylene terephthalate (14.1-30.8%). This study is an essential reference for understanding the characteristics of the variation in microplastics in urban lakes to reduce local microplastic pollution effectively.
{"title":"Distribution of microplastics in surface water of tropical urban lakes: A case study in Ha Noi, Vietnam","authors":"H. Mai, Van Hoi Bui, Thanh Duong Dao, Thanh Duong Nguyen, Danh Thien Nguyen, Toan Khanh Vu, Nguyen Hoang Anh Chu, Manh Quan Tran, Emillie Stragy","doi":"10.15625/2615-9783/18595","DOIUrl":"https://doi.org/10.15625/2615-9783/18595","url":null,"abstract":"Microplastics are nowadays considered ubiquitous pollutants since they have been found widespread in all environmental compartments, particularly in aquatic systems. In urban water bodies, municipal wastewater discharges and overflows of combined storm and wastewater drains are the sources of microplastic pollution. The investigation was performed on the distribution of microplastics in the surface water of three urban lakes: West Lake, Yen So Lake, and Bay Mau Lake, from February 2020 to January 2021. Results show that microplastics were widely and unevenly distributed in all three lakes in Ha Noi and reached a high abundance on the site of West Lake, which is most intensively surrounded by population density, restaurants/bars, and aquaculture activities. Microplastic abundance was highest in February 2020 for all three urban lakes, with 154.92 items m-3 in Bay Mau, 589.46 items m-3 in West Lake, and 139.86 items m-3 in Yen So Lake. There was a decreasing trend in the following sampling times of July, October 2020, and January 2021 (range: Bay Mau: 16.02-59.04 items m-3; West Lake: 36.51-201.08 items m-3; Yen So: 14.07-67.27 items m-3). The dominant microplastics in urban lakes were fibers with a size of 1-3 mm, while microplastic fragments were 0.045-0.3 mm2. Analysis of the chemical composition of microplastics indicated dominance by rayon (13.5-58.5%) and polyethylene terephthalate (14.1-30.8%). This study is an essential reference for understanding the characteristics of the variation in microplastics in urban lakes to reduce local microplastic pollution effectively.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":"1 1","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41963124","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 : 2023-07-24DOI: 10.15625/2615-9783/18576
Lan Luu Thi Phuong, Brooks B. Ellwood, Su Nguyen Khac, Wei- Hsung Wang, Lam Doan Dinh, Dung Nguyen Thanh, Mai Nguyen Thi
To clarify the paleoclimatic events in Northern Vietnam during the Late Quaternary, 132 Con Moong - Thanh Hoa cave sediment samples were collected to analyze magnetic susceptibility (χ), δ18O, and δ13C. Based on the tendency in the value of χ Con Moong's sediment, 14 climate zones that change continuously from warm to cold were identified. These climate zones also correspond to the changing trend of δ18O and δ13C. The period of 14 magnetic zones is referenced from the extrapolation of four 14C data. These alternating cold-warm χ sequences correspond to the Composite Reference Section (CRS) developed in Southern Europe from a χ zonation of multiple caves. The paleoclimate characteristics, including the Heinrich H2 and H1 climate events, the Bølling/Allerød, and Younger Dryas warm-cold events, were elucidated for Northern Viet Nam from ~28.000 to ~10.000 yr BP.
{"title":"High-resolution record of Paleoclimate during the late Quarternary, recovered from Con Moong cave - North Vietnam","authors":"Lan Luu Thi Phuong, Brooks B. Ellwood, Su Nguyen Khac, Wei- Hsung Wang, Lam Doan Dinh, Dung Nguyen Thanh, Mai Nguyen Thi","doi":"10.15625/2615-9783/18576","DOIUrl":"https://doi.org/10.15625/2615-9783/18576","url":null,"abstract":"To clarify the paleoclimatic events in Northern Vietnam during the Late Quaternary, 132 Con Moong - Thanh Hoa cave sediment samples were collected to analyze magnetic susceptibility (χ), δ18O, and δ13C. Based on the tendency in the value of χ Con Moong's sediment, 14 climate zones that change continuously from warm to cold were identified. These climate zones also correspond to the changing trend of δ18O and δ13C. The period of 14 magnetic zones is referenced from the extrapolation of four 14C data. These alternating cold-warm χ sequences correspond to the Composite Reference Section (CRS) developed in Southern Europe from a χ zonation of multiple caves. The paleoclimate characteristics, including the Heinrich H2 and H1 climate events, the Bølling/Allerød, and Younger Dryas warm-cold events, were elucidated for Northern Viet Nam from ~28.000 to ~10.000 yr BP.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46046324","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 : 2023-07-17DOI: 10.15625/2615-9783/18539
Tien Pham Van, Luong Le Hong, Nhan Tran Thanh, Phi Nguyen Quoc, Trinh Phan Trong, Quynh Dinh Thi, Duc Dao Minh, Lan Nguyen Chau, Cuong Nguyen Hai
At approximately 5:00 AM on December 16, 2016, a rapid and deep-seated landslide was triggered by intense rainfall in the Van Hoi irrigation reservoir in Binh Dinh province, Vietnam. The landslide generated an impulsive wave with a height of approximately 20 m, resulting in severe damage to the reservoir operation station. This study investigated the mechanisms behind the landslide's initiation and simulated its initiation and motion processes through site surveys, ring shear tests, and the LS-RAPID simulation model. The physical tests were conducted on two soil samples from the sliding zone to examine the landslide mechanism. The results indicated that only sample 2 (a sand sample of completely weathered gneiss rock) showed a high level of landslide mobility due to its liquefaction phenomena resulting in a rapid pore water pressure development and a significant strength loss. In contrast, sample 1 (a silty sand sample of residual soils) did not exhibit this behavior due to its high shear resistance value at a steady state. The findings suggest that the sliding plane of the Van Hoi landslide formed in the completely weathered gneiss layer, and the high mobility level of sample 2 is primarily responsible for its rapid movement. Notably, the LS-RAPID model successfully reproduced the landslide process using the geotechnical properties obtained in the ring shear experiments. The simulation showed that the Van Hoi deep-seated landslide was initiated from the lower middle slope at a critical value of 0.55 for the pore water pressure ratio and traveled at a high velocity of approximately 37.0 m/s. The consistency between the computer simulation results and the on-site evidence and recorded data highlights the reliability of the LS-RAPID model as a tool for assessing landslide hazards.
{"title":"Mechanism and numerical simulation of a rapid deep-seated landslide in Van Hoi reservoir, Vietnam","authors":"Tien Pham Van, Luong Le Hong, Nhan Tran Thanh, Phi Nguyen Quoc, Trinh Phan Trong, Quynh Dinh Thi, Duc Dao Minh, Lan Nguyen Chau, Cuong Nguyen Hai","doi":"10.15625/2615-9783/18539","DOIUrl":"https://doi.org/10.15625/2615-9783/18539","url":null,"abstract":"At approximately 5:00 AM on December 16, 2016, a rapid and deep-seated landslide was triggered by intense rainfall in the Van Hoi irrigation reservoir in Binh Dinh province, Vietnam. The landslide generated an impulsive wave with a height of approximately 20 m, resulting in severe damage to the reservoir operation station. This study investigated the mechanisms behind the landslide's initiation and simulated its initiation and motion processes through site surveys, ring shear tests, and the LS-RAPID simulation model. The physical tests were conducted on two soil samples from the sliding zone to examine the landslide mechanism. The results indicated that only sample 2 (a sand sample of completely weathered gneiss rock) showed a high level of landslide mobility due to its liquefaction phenomena resulting in a rapid pore water pressure development and a significant strength loss. \u0000In contrast, sample 1 (a silty sand sample of residual soils) did not exhibit this behavior due to its high shear resistance value at a steady state. The findings suggest that the sliding plane of the Van Hoi landslide formed in the completely weathered gneiss layer, and the high mobility level of sample 2 is primarily responsible for its rapid movement. Notably, the LS-RAPID model successfully reproduced the landslide process using the geotechnical properties obtained in the ring shear experiments. The simulation showed that the Van Hoi deep-seated landslide was initiated from the lower middle slope at a critical value of 0.55 for the pore water pressure ratio and traveled at a high velocity of approximately 37.0 m/s. The consistency between the computer simulation results and the on-site evidence and recorded data highlights the reliability of the LS-RAPID model as a tool for assessing landslide hazards.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49237094","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 : 2023-07-10DOI: 10.15625/2615-9783/18500
Truong Tran Xuan, Phuong Doan Thi Nam, Nghi Le Thanh, Nhu Viet-Ha, D. Tien Bui
Accurate prediction models for spatial prediction of forest fire danger play a vital role in predicting forest fires, which can help prevent and mitigate the detrimental effects of such disasters. This research aims to develop a new ensemble learning model, HHO-RSCDT, capable of accurately predicting spatial patterns of forest fire danger. The HHO-RSCDT method combines three distinct components, namely Random Subspace (RS), Credal Decision Tree (CDT), and Harris Hawks Optimizer (HHO). Herein, RS generates a series of subspace datasets, which are subsequently utilized to produce individual CDT classifiers. Then, HHO optimizes the ensemble model, enabling the model to achieve higher predictive performance. The model was trained and validated using a Phu Yen province, Vietnam dataset. The dataset includes 306 forest fire locations and ten influencing factors from the study province. The results showed the capability of the HHO-RSCDT model in predicting forest fire danger, with an accuracy rate of 83.7%, a kappa statistic of 0.674, and an AUC of 0.911. A comparison between the HHO-RSCDT model and two state-of-the-art machine learning methods, i.e., support vector machine (SVM) and random forest (RF), indicated that the HHO-RSCDT model could perform better, making it a valuable tool for modeling forest fire danger. The forest fire danger map produced using this novel model could be a new tool for local authorities in the Phu Yen province, assisting them in managing and protecting the forest ecosystem. By providing a detailed overview of the are as most susceptible to forest fires, the map can help authorities to develop targeted and effective forest management strategies, such as focusing on areas with high fuel loads or implementing controlled burning programs.
{"title":"A novel HHO-RSCDT ensemble learning approach for forest fire danger mapping using GIS","authors":"Truong Tran Xuan, Phuong Doan Thi Nam, Nghi Le Thanh, Nhu Viet-Ha, D. Tien Bui","doi":"10.15625/2615-9783/18500","DOIUrl":"https://doi.org/10.15625/2615-9783/18500","url":null,"abstract":"Accurate prediction models for spatial prediction of forest fire danger play a vital role in predicting forest fires, which can help prevent and mitigate the detrimental effects of such disasters. This research aims to develop a new ensemble learning model, HHO-RSCDT, capable of accurately predicting spatial patterns of forest fire danger. The HHO-RSCDT method combines three distinct components, namely Random Subspace (RS), Credal Decision Tree (CDT), and Harris Hawks Optimizer (HHO). Herein, RS generates a series of subspace datasets, which are subsequently utilized to produce individual CDT classifiers. Then, HHO optimizes the ensemble model, enabling the model to achieve higher predictive performance. The model was trained and validated using a Phu Yen province, Vietnam dataset. The dataset includes 306 forest fire locations and ten influencing factors from the study province. The results showed the capability of the HHO-RSCDT model in predicting forest fire danger, with an accuracy rate of 83.7%, a kappa statistic of 0.674, and an AUC of 0.911. A comparison between the HHO-RSCDT model and two state-of-the-art machine learning methods, i.e., support vector machine (SVM) and random forest (RF), indicated that the HHO-RSCDT model could perform better, making it a valuable tool for modeling forest fire danger. The forest fire danger map produced using this novel model could be a new tool for local authorities in the Phu Yen province, assisting them in managing and protecting the forest ecosystem. By providing a detailed overview of the are as most susceptible to forest fires, the map can help authorities to develop targeted and effective forest management strategies, such as focusing on areas with high fuel loads or implementing controlled burning programs.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47375834","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}
One of the most significant challenges in interpreting magnetic data is to mitigate the influence of the magnetization direction in the shape of the anomalies, especially when reduction to the pole fails to position them over the sources. We propose a balanced high-order filter that has low sensitivity to the direction of the resultant magnetization. We consider an edge-detector filter based on directional analytic signals of the vertically-integrated anomaly field. To ensure that anomalies from shallow and deep sources are equalized, we balance this filter with the magnitude of its two-dimensional Hilbert transform. The proposed filter is tested using aeromagnetic data from Apiaí Terrane, Southern Brazil. The enhanced map is highly correlated with the study area's NE-SW trend of geological structures. Our results highlight the importance of using the directional analytical signals, which help reduce the influence of the magnetization direction, and the balancing filters, for equalizing the signal of shallow and deep causative sources.
{"title":"A balanced edge detector for aeromagnetic data","authors":"Vinicius Theobaldo Jorge, Saulo Pomponet Oliveira, Luan Pham Thanh, Van- Hao Duong","doi":"10.15625/2615-9783/18461","DOIUrl":"https://doi.org/10.15625/2615-9783/18461","url":null,"abstract":"One of the most significant challenges in interpreting magnetic data is to mitigate the influence of the magnetization direction in the shape of the anomalies, especially when reduction to the pole fails to position them over the sources. We propose a balanced high-order filter that has low sensitivity to the direction of the resultant magnetization. We consider an edge-detector filter based on directional analytic signals of the vertically-integrated anomaly field. To ensure that anomalies from shallow and deep sources are equalized, we balance this filter with the magnitude of its two-dimensional Hilbert transform. The proposed filter is tested using aeromagnetic data from Apiaí Terrane, Southern Brazil. The enhanced map is highly correlated with the study area's NE-SW trend of geological structures. Our results highlight the importance of using the directional analytical signals, which help reduce the influence of the magnetization direction, and the balancing filters, for equalizing the signal of shallow and deep causative sources.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44648490","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 : 2023-06-09DOI: 10.15625/2615-9783/18411
Hoang Nguyen Kim, Anh Nong Thi Quynh, Minh Pham, Hieu Pham Trung, Thao Nguyen Thanh
Dak Krong plutonic rocks are found in the Kontum Massif along the N-S-oriented Po Ko River and mainly within the distributive area of the Ben Giang-Que Son granitic bodies. The Hai Van complex crosscuts the Dak-Krong rocks. They are predominantly composed of plagioclase (35-47%), quartz (29-30%), K-feldspar (20-28%), and minor biotite (3-4%). Geochemically, they are characterized by meta- to peraluminous and high-K affinities and straddle I- and S-type granite fields. Zircon U-Pb dating results yielded two main magmatic stages (ca. 258 Ma and ca. 245 Ma) spanning two phases of magmatism presumably accepted as being associated with the Paleo-Tethys Ocean evolution: latest subduction to syn-collisional phases. The Hf isotope data from zircon with eHf(t) ranging between -6.4 and -0.5 indicates a crustal signature. From the results of eHf(t) values along with zircon Hf model ages (TDM2) ranging from 1165-1497 Ma, it is presumable that the Dak Krong plutonic rocks are the product of the partial melting of Mesoproterozoic crustal materials with a negligible contribution of mantle materials. Together with other Permian-Triassic magmatic complexes throughout the Kontum Massif (e.g., Ben Giang-Que Son, Hai Van, and Van Canh complexes) and other plutonic further to the north along the Truong Son Belt and the Song Ma suture zone, the Dak Krong plutonic rocks represent magmatism generated by the amalgamation of Indochina and South China during the Late Permian-Early Triassic, referred to as Indosinian orogeny.
Dak Krong深成岩体位于Po Ko河南北走向的Kontum地块内，主要位于Ben Giang Que Son花岗岩体的分布区内。Hai Van杂岩横切Dak Krong岩石。它们主要由斜长石（35-47%）、石英（29-30%）、钾长石（20-28%）和少量黑云母（3-4%）组成。在地球化学上，它们具有亚发光到过发光和高K亲和力的特征，并横跨I型和S型花岗岩田。锆石U-Pb定年结果产生了两个主要的岩浆阶段（约258 Ma和约245 Ma），跨越了可能被认为与古特提斯洋演化有关的两个岩浆作用阶段：最新的俯冲到同碰撞阶段。eHf（t）在-6.4和-0.5之间的锆石的Hf同位素数据表明存在地壳特征。根据eHf（t）值以及1165-1497 Ma范围内的锆石Hf模型年龄（TDM2）的结果，可以推测Dak Krong深成岩是中元古代地壳物质部分熔融的产物，地幔物质的贡献可以忽略不计。连同整个Kontum Massif的其他二叠纪-三纪岩浆杂岩（例如Ben Giang-Que-Son、Hai-Van和Van Canh杂岩）以及沿着Truong Son带和Song Ma缝合带向北的其他深成岩体，Dak Krong深成岩体代表了晚二叠纪-早三叠世期间中印和华南融合产生的岩浆作用，被称为印支造山运动。
{"title":"Geochemistry and zircon U-Pb geochronology of the Dak Krong plutonic rocks in the Kontum Massif (central Vietnam) and their petrogenetic implications","authors":"Hoang Nguyen Kim, Anh Nong Thi Quynh, Minh Pham, Hieu Pham Trung, Thao Nguyen Thanh","doi":"10.15625/2615-9783/18411","DOIUrl":"https://doi.org/10.15625/2615-9783/18411","url":null,"abstract":"Dak Krong plutonic rocks are found in the Kontum Massif along the N-S-oriented Po Ko River and mainly within the distributive area of the Ben Giang-Que Son granitic bodies. The Hai Van complex crosscuts the Dak-Krong rocks. They are predominantly composed of plagioclase (35-47%), quartz (29-30%), K-feldspar (20-28%), and minor biotite (3-4%). Geochemically, they are characterized by meta- to peraluminous and high-K affinities and straddle I- and S-type granite fields. Zircon U-Pb dating results yielded two main magmatic stages (ca. 258 Ma and ca. 245 Ma) spanning two phases of magmatism presumably accepted as being associated with the Paleo-Tethys Ocean evolution: latest subduction to syn-collisional phases. The Hf isotope data from zircon with eHf(t) ranging between -6.4 and -0.5 indicates a crustal signature. From the results of eHf(t) values along with zircon Hf model ages (TDM2) ranging from 1165-1497 Ma, it is presumable that the Dak Krong plutonic rocks are the product of the partial melting of Mesoproterozoic crustal materials with a negligible contribution of mantle materials. Together with other Permian-Triassic magmatic complexes throughout the Kontum Massif (e.g., Ben Giang-Que Son, Hai Van, and Van Canh complexes) and other plutonic further to the north along the Truong Son Belt and the Song Ma suture zone, the Dak Krong plutonic rocks represent magmatism generated by the amalgamation of Indochina and South China during the Late Permian-Early Triassic, referred to as Indosinian orogeny.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43395820","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 : 2023-06-08DOI: 10.15625/2615-9783/18410
Paul Gautier Kamto, E. Oksum, Luan Thanh Pham, J. Kamguia
The Douala sedimentary basin (DSB) is an area of interest because of its hydrocarbon potential. Geophysical investigations in this basin are necessary to understand its structural features better. In this study, we aimed to highlight the major lineaments of the DSB by interpreting gravity data using advanced edge detection filters based on various combinations of the horizontal and vertical gradients of the field, namely the total horizontal gradient (THG), analytical signal (AS), theta map (TM), gradient amplitude of the vertical derivative (THG_VD), the tilt angle of the total horizontal gradient amplitude (TAHG) and a novel edge detector based on the soft sign function (SF). These filters were first tested on synthetic data of a simple density model to examine their effectiveness. The results show that the edges of the model structures can be visualized with greater accuracy using the TAHG and SF filters compared to the results from the others. Further, although the TAHG and SF filters produced good results in identifying shallow and deep structures, solutions from SF proved to be better at delineating edges. Next, we applied these edge detection filters to the residual gravity anomaly of the study area obtained after a filtering process on the complete Bouguer anomaly. The SF filter clearly and accurately identifies the major structural features. The existence and location of previously unidentified lineaments have been shown. Most of the lineaments of the DSB extracted by this study provide geometric information on the lateral distribution of depositional successions filling the basin. The structural features are mainly concentrically from the volcanic center of Mount Cameroon and show that the DSB has probably been affected by earthquakes from the permanent activities of the Cameroon volcanic line since the Cretaceous. The highlighted lineaments of the DSB obtained from this study may shed light on future studies to improve mineral/hydrocarbon exploitation and update the area's geological/tectonic information.
{"title":"Contribution of advanced edge detection filters for the structural mapping of the Douala Sedimentary Basin along the Gulf of Guinea","authors":"Paul Gautier Kamto, E. Oksum, Luan Thanh Pham, J. Kamguia","doi":"10.15625/2615-9783/18410","DOIUrl":"https://doi.org/10.15625/2615-9783/18410","url":null,"abstract":"The Douala sedimentary basin (DSB) is an area of interest because of its hydrocarbon potential. Geophysical investigations in this basin are necessary to understand its structural features better. In this study, we aimed to highlight the major lineaments of the DSB by interpreting gravity data using advanced edge detection filters based on various combinations of the horizontal and vertical gradients of the field, namely the total horizontal gradient (THG), analytical signal (AS), theta map (TM), gradient amplitude of the vertical derivative (THG_VD), the tilt angle of the total horizontal gradient amplitude (TAHG) and a novel edge detector based on the soft sign function (SF). These filters were first tested on synthetic data of a simple density model to examine their effectiveness. The results show that the edges of the model structures can be visualized with greater accuracy using the TAHG and SF filters compared to the results from the others. \u0000Further, although the TAHG and SF filters produced good results in identifying shallow and deep structures, solutions from SF proved to be better at delineating edges. Next, we applied these edge detection filters to the residual gravity anomaly of the study area obtained after a filtering process on the complete Bouguer anomaly. The SF filter clearly and accurately identifies the major structural features. The existence and location of previously unidentified lineaments have been shown. Most of the lineaments of the DSB extracted by this study provide geometric information on the lateral distribution of depositional successions filling the basin. The structural features are mainly concentrically from the volcanic center of Mount Cameroon and show that the DSB has probably been affected by earthquakes from the permanent activities of the Cameroon volcanic line since the Cretaceous. The highlighted lineaments of the DSB obtained from this study may shed light on future studies to improve mineral/hydrocarbon exploitation and update the area's geological/tectonic information.","PeriodicalId":23639,"journal":{"name":"VIETNAM JOURNAL OF EARTH SCIENCES","volume":" ","pages":""},"PeriodicalIF":1.5,"publicationDate":"2023-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43097792","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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