Martín T. Vera-San, M. Palacios, G. Ormazabal, E. González, L. Gutierrez
Ecuador is a country with frequent seismic and tsunamigenic events due to its close location to a subduction zone between the plates of Nazca and South America. The main objective of this study was to assess the vulnerability of the population and infrastructure of the city of Manta-Ecuador towards a tsunami event. To evaluate the infrastructures, fragility and vulnerability index functions were used, while only fragility functions were considered for the population. Manta has a population of 249,868 permanent inhabitants. The most severe tsunami scenario impacting inhabitants and buildings was selected considering historical data, mathematical modeling, characteristics of infrastructure and population. To perform the simulation, a hypocenter was proposed: 40 km northwest of Manta, 3 km oceanic depth and magnitude moment 8. The simulation results showed floods in 6% of the total area of the city. The analysis conducted by fragility functions indicated that from 2,040 exposed people, 468 would be affected, in particular minors, elderly and disabled groups, not accounting tourists. Also, 221 structures would be affected from 843 exposed in the flooded zones with a maximum flood depth higher than 5 m representing 26% and 0.2 % of the exposed and total buildings in the city respectively. The results of this study would assist in identifying risky and safe areas, shelter buildings, routes and evacuation times during a tsunamigenic event.
{"title":"Population and infrastructure vulnerability study under a tsunami scenario in the city of Manta-Ecuador","authors":"Martín T. Vera-San, M. Palacios, G. Ormazabal, E. González, L. Gutierrez","doi":"10.25303/1603da01012","DOIUrl":"https://doi.org/10.25303/1603da01012","url":null,"abstract":"Ecuador is a country with frequent seismic and tsunamigenic events due to its close location to a subduction zone between the plates of Nazca and South America. The main objective of this study was to assess the vulnerability of the population and infrastructure of the city of Manta-Ecuador towards a tsunami event. To evaluate the infrastructures, fragility and vulnerability index functions were used, while only fragility functions were considered for the population. Manta has a population of 249,868 permanent inhabitants. The most severe tsunami scenario impacting inhabitants and buildings was selected considering historical data, mathematical modeling, characteristics of infrastructure and population. To perform the simulation, a hypocenter was proposed: 40 km northwest of Manta, 3 km oceanic depth and magnitude moment 8. The simulation results showed floods in 6% of the total area of the city. The analysis conducted by fragility functions indicated that from 2,040 exposed people, 468 would be affected, in particular minors, elderly and disabled groups, not accounting tourists. Also, 221 structures would be affected from 843 exposed in the flooded zones with a maximum flood depth higher than 5 m representing 26% and 0.2 % of the exposed and total buildings in the city respectively. The results of this study would assist in identifying risky and safe areas, shelter buildings, routes and evacuation times during a tsunamigenic event.","PeriodicalId":50576,"journal":{"name":"Disaster Advances","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43662899","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}
Arpit A. Parikh, A. Desai, S. R. Gandhi, A. Shroff
A jack-up structure is a bottom-mounted floating unit having an adjustable hull and movable legs. Particular jack-up structures are more susceptible to hazards under environmental loads during their operation and life cycle in the ocean. Authors attempted here to evaluate vertical load carrying capacity of soil and predicting its behaviour. Simulation of loaddeformation behavior under axial compression has been carried out for advancing research. The entire study has been carried out using three-dimensional finite element-based software Plaxis 3D A.E. 2017. The geometrical variation of substructure spud can have an inverted spud at the centre bottom from 1200 to 1800 studied for knowing behaviour under axial compression, axial tension and lateral forces. The simulated numerical model is used to develop empirical expressions for axial capacities estimation. The numerical analysis results indicate that spud can have an inverted angle of cone 1300 which is most beneficial under the static combined vertical, moment and horizontal loading (3D loading) in marine clay. The axial load carrying capacities in compression, tension and lateral loading follow the same sequence in ascending order from 1800,1750, 1500, 1300 and highest in 1200. Stiffness and undrained shear strength of soft clay contribute more than the diameter of the spud and embedment depth in compression and tension.
自升式结构是一种底部安装的浮动单元，具有可调节的船体和可移动的支腿。特定的自升式结构在海洋中的操作和生命周期中更容易受到环境载荷的危害。作者试图评估土壤的垂直承载能力并预测其行为。为了推进研究，对轴压作用下的载荷变形行为进行了模拟。整个研究是使用基于三维有限元的软件Plaxis 3D A.E.2017进行的。底座开孔的几何变化可以在中心底部有一个倒置的开孔，从1200到1800进行研究，以了解在轴向压缩、轴向张力和侧向力下的行为。模拟数值模型用于开发轴向承载力估计的经验表达式。数值分析结果表明，在海洋粘土中的静态垂直、力矩和水平组合载荷（3D载荷）下，开钻可以具有1300的倒锥角，这是最有利的。压缩、拉伸和横向载荷的轴向承载能力从1800、1750、1500、1300按升序排列，最高值为1200。软粘土的刚度和不排水抗剪强度在压缩和拉伸中的贡献大于开孔直径和埋置深度。
{"title":"Numerical Assessment of Jackup Spudcan Foundations by varying Angle of Spud in 3d Fem in Geotechnical Engineering","authors":"Arpit A. Parikh, A. Desai, S. R. Gandhi, A. Shroff","doi":"10.25303/1603da023034","DOIUrl":"https://doi.org/10.25303/1603da023034","url":null,"abstract":"A jack-up structure is a bottom-mounted floating unit having an adjustable hull and movable legs. Particular jack-up structures are more susceptible to hazards under environmental loads during their operation and life cycle in the ocean. Authors attempted here to evaluate vertical load carrying capacity of soil and predicting its behaviour. Simulation of loaddeformation behavior under axial compression has been carried out for advancing research. The entire study has been carried out using three-dimensional finite element-based software Plaxis 3D A.E. 2017. The geometrical variation of substructure spud can have an inverted spud at the centre bottom from 1200 to 1800 studied for knowing behaviour under axial compression, axial tension and lateral forces. The simulated numerical model is used to develop empirical expressions for axial capacities estimation. The numerical analysis results indicate that spud can have an inverted angle of cone 1300 which is most beneficial under the static combined vertical, moment and horizontal loading (3D loading) in marine clay. The axial load carrying capacities in compression, tension and lateral loading follow the same sequence in ascending order from 1800,1750, 1500, 1300 and highest in 1200. Stiffness and undrained shear strength of soft clay contribute more than the diameter of the spud and embedment depth in compression and tension.","PeriodicalId":50576,"journal":{"name":"Disaster Advances","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-02-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45734308","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}
K. Ramanath, M. Sivagami, P. Radha, V. Balaji, L. Shyamala
This study explores the greatest yearly precipitation pattern utilizing the Mann-Kendall test and Sen’s slope strategy and assesses the importance of variability utilizing precipitation of all Indian weather stations followed by spectral analysis. The information of these weather conditions stations from 1901 to 2020 was utilized. Original Mann-Kendall test, Modified Mann-Kendall test using Pre-Whitening method, Correlated Seasonal Mann-Kendall test and Sen’s slope test were applied to identify homogeneity in the information and detected the behaviour of the signal by using spectral analysis. Besides, the critical negative pattern was recorded for overall annual precipitation in some of the regions of North India. In view of the discoveries of progress identification, the most probable year of progress recognition happened principally after 1960 for a huge part of rainfall stations. The rising precipitation pattern was seen between the tenure 1901-1970 while a huge decay in precipitation was seen after 1980. The outcomes from this pattern re-analysis information show that expanding or diminishing precipitation convective rate raised low effect and insufficient in an upward direction coordinated dissimilarity. Discoveries of the review consider the availability of rainfall assets and expansion later on water interest. Also, the resultant spectral signal shows a high peak at Yunnan which is located in Kerala.
{"title":"Trend Analysis of Rain Precipitation for Indian States using 1901-2020 IMD dataset","authors":"K. Ramanath, M. Sivagami, P. Radha, V. Balaji, L. Shyamala","doi":"10.25303/1602da041049","DOIUrl":"https://doi.org/10.25303/1602da041049","url":null,"abstract":"This study explores the greatest yearly precipitation pattern utilizing the Mann-Kendall test and Sen’s slope strategy and assesses the importance of variability utilizing precipitation of all Indian weather stations followed by spectral analysis. The information of these weather conditions stations from 1901 to 2020 was utilized. Original Mann-Kendall test, Modified Mann-Kendall test using Pre-Whitening method, Correlated Seasonal Mann-Kendall test and Sen’s slope test were applied to identify homogeneity in the information and detected the behaviour of the signal by using spectral analysis. Besides, the critical negative pattern was recorded for overall annual precipitation in some of the regions of North India. In view of the discoveries of progress identification, the most probable year of progress recognition happened principally after 1960 for a huge part of rainfall stations. The rising precipitation pattern was seen between the tenure 1901-1970 while a huge decay in precipitation was seen after 1980. The outcomes from this pattern re-analysis information show that expanding or diminishing precipitation convective rate raised low effect and insufficient in an upward direction coordinated dissimilarity. Discoveries of the review consider the availability of rainfall assets and expansion later on water interest. Also, the resultant spectral signal shows a high peak at Yunnan which is located in Kerala.","PeriodicalId":50576,"journal":{"name":"Disaster Advances","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45526509","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}
Flood is a natural disaster when causes damage and loss, especially in urban areas that are inhabited by many people and have many properties. The goal of this study is to map rapidly the flooded areas in North Aceh district on January, 5 2022 using multi-temporal SAR Sentinel-1A images through visual interpretation and semi-automated interpretation methods including thresholding and support vector machine (SVM). Visual interpretation relied on multi-polarization image of VH-VV with median filters of 3x3 and 5x5. This study produced the flooded area maps from three methods used with an area of each method: visual interpretation (422.86 ha), thresholding (791.22 ha) and SVM (1084.76 ha). According to the comparison with the result generated from visual interpretation using Planetscope-3A, SVM method has the similar result in the flooded areas with an area of 1001.52 ha. This study also analysed impact of flood event against land cover referring to Sentinel-2 10-Meter Land Use/Land Cover of ESRI and showed that class of cultivated crops is most affected. Results show that this study can be very helpful in damage and loss assessment of flood event and can be reference for urban planning management in order to face the climate change.
{"title":"Visual and semi-automated interpretation methods for urban flood detection using SAR Sentinel-1A image: study case in North Aceh Regency, Indonesia","authors":"Muhammad Fadhil Ayyasy, A. .","doi":"10.25303/1602da030040","DOIUrl":"https://doi.org/10.25303/1602da030040","url":null,"abstract":"Flood is a natural disaster when causes damage and loss, especially in urban areas that are inhabited by many people and have many properties. The goal of this study is to map rapidly the flooded areas in North Aceh district on January, 5 2022 using multi-temporal SAR Sentinel-1A images through visual interpretation and semi-automated interpretation methods including thresholding and support vector machine (SVM). Visual interpretation relied on multi-polarization image of VH-VV with median filters of 3x3 and 5x5. This study produced the flooded area maps from three methods used with an area of each method: visual interpretation (422.86 ha), thresholding (791.22 ha) and SVM (1084.76 ha). According to the comparison with the result generated from visual interpretation using Planetscope-3A, SVM method has the similar result in the flooded areas with an area of 1001.52 ha. This study also analysed impact of flood event against land cover referring to Sentinel-2 10-Meter Land Use/Land Cover of ESRI and showed that class of cultivated crops is most affected. Results show that this study can be very helpful in damage and loss assessment of flood event and can be reference for urban planning management in order to face the climate change.","PeriodicalId":50576,"journal":{"name":"Disaster Advances","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45375044","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}
A naturally occurring geological formation is precariously balanced rocks (PBRs) which might easily topple by an earthquake with severe ground motion. These rocks have been at the same place for many years. Strong ground accelerations have not occurred in the area for thousands of years as shown by the zone of unstable rocks. So, they are significant in both the engineering and seismological domains since they provide source of data for the maximum earthquake ground motion occurring at a site over the rock’s life time. The precariously balanced rock taken for this study is Krishna Butter Ball which is in Mahabalipuram, Chengalpattu district. In the numerical analysis, the peak ground acceleration at which the Krishna butter ball may topple is obtained. To identify the possible future earthquake, deterministic seismic hazard analysis has been carried out for Chengalpattu district. For this analysis, fault details have been obtained from Geological Survey of India. Arc map 10.1 version in Geographical Information System (GIS) platform is used for the interpretation of data like fault length, source (fault) to site (Mahabalipuram) distance from the fault details given by GSI. From the results of Deterministic Seismic Hazard Analysis (DSHA), it is observed that the possible future earthquake may have the magnitude in the range of 6.03 to 7.9. The computed peak ground acceleration (PGA) value corresponding to those magnitude ranges from 0.027g to 0.49g. The maximum PGA value 0.49g corresponds to the Palar river fault which is just 28.53 km away from the Krishna butter ball. From the results of numerical analysis, the behavior of Krishna butter ball for three different PGA i.e. 0.05g, 0.1g, 0.15g has been observed. Newmark sliding block analysis said that the rock may topple at the PGA of 0.35g. From this it can be concluded that the toppling acceleration of Krishna butter ball is relatively low.
{"title":"Behaviour of Precariously Balanced Rocks under Seismic Excitation","authors":"K. Premalatha, S. Angammal, K. Raja","doi":"10.25303/1602da07012","DOIUrl":"https://doi.org/10.25303/1602da07012","url":null,"abstract":"A naturally occurring geological formation is precariously balanced rocks (PBRs) which might easily topple by an earthquake with severe ground motion. These rocks have been at the same place for many years. Strong ground accelerations have not occurred in the area for thousands of years as shown by the zone of unstable rocks. So, they are significant in both the engineering and seismological domains since they provide source of data for the maximum earthquake ground motion occurring at a site over the rock’s life time. The precariously balanced rock taken for this study is Krishna Butter Ball which is in Mahabalipuram, Chengalpattu district. In the numerical analysis, the peak ground acceleration at which the Krishna butter ball may topple is obtained. To identify the possible future earthquake, deterministic seismic hazard analysis has been carried out for Chengalpattu district. For this analysis, fault details have been obtained from Geological Survey of India. Arc map 10.1 version in Geographical Information System (GIS) platform is used for the interpretation of data like fault length, source (fault) to site (Mahabalipuram) distance from the fault details given by GSI. From the results of Deterministic Seismic Hazard Analysis (DSHA), it is observed that the possible future earthquake may have the magnitude in the range of 6.03 to 7.9. The computed peak ground acceleration (PGA) value corresponding to those magnitude ranges from 0.027g to 0.49g. The maximum PGA value 0.49g corresponds to the Palar river fault which is just 28.53 km away from the Krishna butter ball. From the results of numerical analysis, the behavior of Krishna butter ball for three different PGA i.e. 0.05g, 0.1g, 0.15g has been observed. Newmark sliding block analysis said that the rock may topple at the PGA of 0.35g. From this it can be concluded that the toppling acceleration of Krishna butter ball is relatively low.","PeriodicalId":50576,"journal":{"name":"Disaster Advances","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49012519","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}
Joshua R. Melwyn, R. Rajaperumal, J. Saravanavel, S. Ramasamy, K. Palanivel
The drainage fabric is the reflection of the surface and sub-surface geological systems and processes of the Earth. In this context, the State of Kerala, has prolific network of drainages due to the unique physiographic conditions and it was studied to map the drainage fabric and the anomalies using IRS FCC wrapped DEM of SRTM data of the Southern parts of Kerala. The study revealed the occurrence of larger centrifugal radial drainages conspicuously in a number of places. Such drainages seem to indicate the phenomenon of doming due to the still prevalent northerly directed compressive force related to the post collision tectonics and the east north easterly compressive force due to the rising of the Carlsberg ridge in the Arabian Sea. These both forces in combination might have resulted in the phenomenon of simultaneous cross folding leading to the formation of the domes. The active tectonics have serious implications on the natural disasters in general and the tectonically vibrant Kerala State in particular, therefore the drainage anomalies of Kerala warrant demanding studies.
{"title":"Centrifugal radial drainages and their geological significance in southern Kerala, India","authors":"Joshua R. Melwyn, R. Rajaperumal, J. Saravanavel, S. Ramasamy, K. Palanivel","doi":"10.25303/1602da025029","DOIUrl":"https://doi.org/10.25303/1602da025029","url":null,"abstract":"The drainage fabric is the reflection of the surface and sub-surface geological systems and processes of the Earth. In this context, the State of Kerala, has prolific network of drainages due to the unique physiographic conditions and it was studied to map the drainage fabric and the anomalies using IRS FCC wrapped DEM of SRTM data of the Southern parts of Kerala. The study revealed the occurrence of larger centrifugal radial drainages conspicuously in a number of places. Such drainages seem to indicate the phenomenon of doming due to the still prevalent northerly directed compressive force related to the post collision tectonics and the east north easterly compressive force due to the rising of the Carlsberg ridge in the Arabian Sea. These both forces in combination might have resulted in the phenomenon of simultaneous cross folding leading to the formation of the domes. The active tectonics have serious implications on the natural disasters in general and the tectonically vibrant Kerala State in particular, therefore the drainage anomalies of Kerala warrant demanding studies.","PeriodicalId":50576,"journal":{"name":"Disaster Advances","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42473856","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}
Disaster vulnerability that occurs in Indonesia is closely related to geographical and geological conditions. The National Disaster Management Agency (BNPB) stated that throughout 2021, the number of natural disasters reached 3,058 events. This condition certainly needs to be addressed with disaster mitigation. One of the most active volcanoes in the world is Merapi which is located in Sleman, Boyolali and Magelang regencies. Law no. 24 of 2007 states that there are communities that are vulnerable to disasters, namely children, the elderly, women and people with disabilities who need mitigation both before, during and after the eruption. This study aims to analyze the priority factors in the disaster mitigation process. The research method uses a sequential mixed method with a quantitative analytical hierarchy process (AHP) analysis tool. The results showed that there were 3 main factors, namely 1) institutional, 2) external and 3) internal in order. Each of them is reduced to a derivative factor of assistance local government, the character of local leaders and geographic actors. External factors consist of disaster mitigation literacy, infrastructure preparation, early warning system and community preparation. Meanwhile, internal factors consist of education, regional potential, social capital and sense of belonging.
{"title":"Priority Factors in the Disaster Mitigation Process for Vulnerable Communities: Case Study of Mount Merapi","authors":"Gravitiani Evi, M. Izza, Prasetyani Dwi, S. .","doi":"10.25303/1602da01006","DOIUrl":"https://doi.org/10.25303/1602da01006","url":null,"abstract":"Disaster vulnerability that occurs in Indonesia is closely related to geographical and geological conditions. The National Disaster Management Agency (BNPB) stated that throughout 2021, the number of natural disasters reached 3,058 events. This condition certainly needs to be addressed with disaster mitigation. One of the most active volcanoes in the world is Merapi which is located in Sleman, Boyolali and Magelang regencies. Law no. 24 of 2007 states that there are communities that are vulnerable to disasters, namely children, the elderly, women and people with disabilities who need mitigation both before, during and after the eruption. This study aims to analyze the priority factors in the disaster mitigation process. The research method uses a sequential mixed method with a quantitative analytical hierarchy process (AHP) analysis tool. The results showed that there were 3 main factors, namely 1) institutional, 2) external and 3) internal in order. Each of them is reduced to a derivative factor of assistance local government, the character of local leaders and geographic actors. External factors consist of disaster mitigation literacy, infrastructure preparation, early warning system and community preparation. Meanwhile, internal factors consist of education, regional potential, social capital and sense of belonging.","PeriodicalId":50576,"journal":{"name":"Disaster Advances","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42636523","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}
In the age of global climate change, land use and land cover mapping help us to understand the vital modifications taking place in our environment. LULC mapping assumes great significance in planning, management of resources and keeping track of various programmes at different levels. The data acquired from the land use and land cover investigations are vital for policy formulation and sustainable development of our towns, cities and villages and also to track the disorganized growth of urban areas. Tourism is a tool for economic development in many developing countries of the world. The unplanned tourism growth has led to many ecological problems. This study makes an earnest effort to examine the LULC change using the transition model in the Bardez taluka, which is a well-known global tourist destination in Goa, India. The study has been investigated by using satellite imageries and GIS technologies have been used to analyse the changes occurring in LULC patterns for the years 1991, 2001 and 2021. The result indicates that the area under the built-up class has increased substantially by 11.12 sq. km. as a result of the rise in commercialization, tourism growth and tourism-related activities. Bardez taluka is known for some of the most breath-taking beaches in the world. During 2019-20, just before Covid-19, about 25, 33,234 domestic and 2, 74,840 foreign tourists visited the enchanting beaches of Bardez taluka. Land use classes such as residential, commercial and services, industrial, transportation and utilities also witnessed the growth in their land use and land cover classes whereas classes like agricultural land, coconut plantation, cashew plantation, barren land, DM and FDM forest land, open scrub and fairly dense scrub witnessed a negative change in their class values.
{"title":"Transition Modelling of Land Use Land Cover Dynamics in Bardez Taluka of Goa-India (1991-2021)","authors":"Gaonkar Venkatesh G. Prabhu, F. Nadaf","doi":"10.25303/1602da013024","DOIUrl":"https://doi.org/10.25303/1602da013024","url":null,"abstract":"In the age of global climate change, land use and land cover mapping help us to understand the vital modifications taking place in our environment. LULC mapping assumes great significance in planning, management of resources and keeping track of various programmes at different levels. The data acquired from the land use and land cover investigations are vital for policy formulation and sustainable development of our towns, cities and villages and also to track the disorganized growth of urban areas. Tourism is a tool for economic development in many developing countries of the world. The unplanned tourism growth has led to many ecological problems. This study makes an earnest effort to examine the LULC change using the transition model in the Bardez taluka, which is a well-known global tourist destination in Goa, India. The study has been investigated by using satellite imageries and GIS technologies have been used to analyse the changes occurring in LULC patterns for the years 1991, 2001 and 2021. The result indicates that the area under the built-up class has increased substantially by 11.12 sq. km. as a result of the rise in commercialization, tourism growth and tourism-related activities. Bardez taluka is known for some of the most breath-taking beaches in the world. During 2019-20, just before Covid-19, about 25, 33,234 domestic and 2, 74,840 foreign tourists visited the enchanting beaches of Bardez taluka. Land use classes such as residential, commercial and services, industrial, transportation and utilities also witnessed the growth in their land use and land cover classes whereas classes like agricultural land, coconut plantation, cashew plantation, barren land, DM and FDM forest land, open scrub and fairly dense scrub witnessed a negative change in their class values.","PeriodicalId":50576,"journal":{"name":"Disaster Advances","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42106702","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}
T. Tran, Mon Danh, M. Duong, Tung H. Luu, Dung Nguyen
This study examined changes in leaf area index (LAI) patterns corresponding to vegetation cover dynamics across space and time in the Vietnamese Central Highlands. We generated the mean annual LAI values during the 2002–2021 period using the MCD15A3H MODIS time-series based on the Google Earth Engine platform. Afterwards, a spatial linear regression was applied to examine spatiotemporal LAI variations in the study area. Results show that the mean LAI values between 2 and 3 covered almost all of the study area. The significant decreasing and increasing patterns in LAI trends were discovered for all provinces, but a decreasing pattern mainly distributed in Dak Nong and Gia Lai provinces. Besides, in terms of vegetation categories, an increasing LAI trend was explored in perennial croplands, while a decreasing LAI trend was found in forests and shrubs. These trends considered a conversion in land use purposes in the study area from forests to croplands over the past two decades. Additionally, the discovered information contributed to highlighting forest degradation and deforestation associated with anthropogenic activities in the region. Our study of LAI variations could assist future investigations into the affecting factors of deforestation and forest degradation and it also enables policy makers, planners and foresters to propose potential strategies for sustainable management in the future. Notably, our study shows the efficiency of the LAI MCD15A3H MODIS application for vegetation cover at a regional analysis.
{"title":"Estimating Long-term Trend in Leaf Area Index Variations in the Vietnamese Central Highlands using Time Series LAI MODIS Imagery","authors":"T. Tran, Mon Danh, M. Duong, Tung H. Luu, Dung Nguyen","doi":"10.25303/1601da023029","DOIUrl":"https://doi.org/10.25303/1601da023029","url":null,"abstract":"This study examined changes in leaf area index (LAI) patterns corresponding to vegetation cover dynamics across space and time in the Vietnamese Central Highlands. We generated the mean annual LAI values during the 2002–2021 period using the MCD15A3H MODIS time-series based on the Google Earth Engine platform. Afterwards, a spatial linear regression was applied to examine spatiotemporal LAI variations in the study area. Results show that the mean LAI values between 2 and 3 covered almost all of the study area. The significant decreasing and increasing patterns in LAI trends were discovered for all provinces, but a decreasing pattern mainly distributed in Dak Nong and Gia Lai provinces. Besides, in terms of vegetation categories, an increasing LAI trend was explored in perennial croplands, while a decreasing LAI trend was found in forests and shrubs. These trends considered a conversion in land use purposes in the study area from forests to croplands over the past two decades. Additionally, the discovered information contributed to highlighting forest degradation and deforestation associated with anthropogenic activities in the region. Our study of LAI variations could assist future investigations into the affecting factors of deforestation and forest degradation and it also enables policy makers, planners and foresters to propose potential strategies for sustainable management in the future. Notably, our study shows the efficiency of the LAI MCD15A3H MODIS application for vegetation cover at a regional analysis.","PeriodicalId":50576,"journal":{"name":"Disaster Advances","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46078236","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}
Flood is the most common and natural disaster of the world. Fluvial flood basically occurred by the combination of hydro-geomorphological effect. But during the flood risk assessment, geomorphological condition analysis is ignored. Present research aimed to focus on flood assessment in the lower part of the Ajay river basin on the basis of present hydro-geomorphological conditions. Flood character analysis on the basis of present hydro-geomorphological status of the river also helps in the management strategy formulation. Remote sensing data, traditional topographical sheet and field work reach the present status of the river. Different layers of hydrological and geomorphological parameters are prepared in the Geographic Information System (GIS) field as per objective. By using the Analytical Hierarchy Process (AHP), a decision based on comparison matrix, weighted score is extracted and in the field of GIS, the flood area is predicted. According to the categories of hazards, the extracted flood area is classified into three zones. Result depicts that 5 blocks lie in the high hazards prone area and 5 blocks are moderate. Hazards prone and validation prove that the model is 87 % correct in case of overall accuracy assessment and 81 % correct in case of Kappa statistics. Both the results of validation prove the suitability of the model.
{"title":"Flood hazards and risk prediction by using the Analytical Hierarchy Process on GIS platform: a case study in lower Ajay basin, India","authors":"K. Mondal, Sutapa Saha, Pritam Aitch","doi":"10.25303/1601da01013","DOIUrl":"https://doi.org/10.25303/1601da01013","url":null,"abstract":"Flood is the most common and natural disaster of the world. Fluvial flood basically occurred by the combination of hydro-geomorphological effect. But during the flood risk assessment, geomorphological condition analysis is ignored. Present research aimed to focus on flood assessment in the lower part of the Ajay river basin on the basis of present hydro-geomorphological conditions. Flood character analysis on the basis of present hydro-geomorphological status of the river also helps in the management strategy formulation. Remote sensing data, traditional topographical sheet and field work reach the present status of the river. Different layers of hydrological and geomorphological parameters are prepared in the Geographic Information System (GIS) field as per objective. By using the Analytical Hierarchy Process (AHP), a decision based on comparison matrix, weighted score is extracted and in the field of GIS, the flood area is predicted. According to the categories of hazards, the extracted flood area is classified into three zones. Result depicts that 5 blocks lie in the high hazards prone area and 5 blocks are moderate. Hazards prone and validation prove that the model is 87 % correct in case of overall accuracy assessment and 81 % correct in case of Kappa statistics. Both the results of validation prove the suitability of the model.","PeriodicalId":50576,"journal":{"name":"Disaster Advances","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47312753","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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