Pub Date : 2024-12-29DOI: 10.1016/j.geomorph.2024.109585
Xingmin Liu , Yongzhi Wang , Lulu Qiao , Yi Zhong , Hongbing Miao
Straits are important pathways for material exchange in the ocean, and understanding the dynamics of these conduits is critical for quantifying regional and global sediment balances. Many straits contain complex island chains, yet little is understood about the role of these mid strait islands in controlling hydrodynamics and sediment dynamics. We examine the impact of island distribution on sediment transport in the Bohai Strait using in-situ observations and numerical modeling. Observations of water level, velocity, and suspended-sediment concentration around an archipelago in the Bohai Strait demonstrated that increases in water velocity and sediment flux were generated by Island topography. The model results showed that the distributions of current and sediment transport in the Bohai Strait were mainly controlled by the barotropic gradient force, and the presence of islands increased the sea level height difference across the axis of the strait. This change in sea level height enhanced the current velocity between islands, improved the efficiency of suspended sediment transport, and thus increased suspended sediment transport. Altering the width/average depth ratios of the channel and distributions of islands affected the total suspended sediment flux. Through many numerical experiments, we proposed a simple parametric equation, hoping to provide some reference for the simulation of sediment transport in complex topography.
{"title":"Effects of islands on sediment transport in a narrow strait: Strengthening or choking?","authors":"Xingmin Liu , Yongzhi Wang , Lulu Qiao , Yi Zhong , Hongbing Miao","doi":"10.1016/j.geomorph.2024.109585","DOIUrl":"10.1016/j.geomorph.2024.109585","url":null,"abstract":"<div><div>Straits are important pathways for material exchange in the ocean, and understanding the dynamics of these conduits is critical for quantifying regional and global sediment balances. Many straits contain complex island chains, yet little is understood about the role of these mid strait islands in controlling hydrodynamics and sediment dynamics. We examine the impact of island distribution on sediment transport in the Bohai Strait using in-situ observations and numerical modeling. Observations of water level, velocity, and suspended-sediment concentration around an archipelago in the Bohai Strait demonstrated that increases in water velocity and sediment flux were generated by Island topography. The model results showed that the distributions of current and sediment transport in the Bohai Strait were mainly controlled by the barotropic gradient force, and the presence of islands increased the sea level height difference across the axis of the strait. This change in sea level height enhanced the current velocity between islands, improved the efficiency of suspended sediment transport, and thus increased suspended sediment transport. Altering the width/average depth ratios of the channel and distributions of islands affected the total suspended sediment flux. Through many numerical experiments, we proposed a simple parametric equation, hoping to provide some reference for the simulation of sediment transport in complex topography.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109585"},"PeriodicalIF":3.1,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134156","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-26DOI: 10.1016/j.geomorph.2024.109584
Yanjie Sun , Xiaolong Song , Haijue Xu , Yuchuan Bai
Quantifying long-term morphological evolution of fluvial reach in river tail channels is crucial for floodplain management and ecological conservation in large river systems, yet remains challenging due to inherent complexities and uncertainties. This study introduces an integrated stochastic-data modeling framework to simulate the fluvial reach dynamics in the Yellow River tail channel, China. Stochastic differential equations (SDEs) incorporate white and correlated noise to capture stochastic responses of reach-averaged hydraulic geometry relationships governing channel changes. Gated recurrent unit (GRU) networks and gradient boosting machine algorithms extract signals from water-sediment data to forecast drivers like mean discharge and sediment load during the flood season. The models demonstrate strong performance, with the R2 values for width, depth, and migration rate predictions reaching a maximum of 0.859, 0.445, and 0.540, respectively. The model experiments capture uncertainties and deliver probabilistic projections of future channel changes, with mean forecasts for this century indicating 50 % decrease in channel width, relatively stable depth (±5 % variation), and 80 % reduction in migration rate by 2100 relative to 2022 levels. While, integrated simulations with a channel centerline evolution model not only reveal significant and inescapable migration trends in the studied reach but also identify localized high-risk zones (e.g., the north-south migration of the river segments near the Qing 7 section could be up to 250 m in the future). Strategic interventions (dredging, fortifications, sediment replenishments) are recommended to balance navigability, habitability and ecological needs. The innovative methodology establishes foundations for advancing predictive process-based modeling of morphodynamic systems under climate shifts and anthropogenic stressors.
{"title":"Navigating uncertainty: Stochastic simulation prediction of the Yellow River tail channel (fluvial reach) and its implications on 21st century floodplain management","authors":"Yanjie Sun , Xiaolong Song , Haijue Xu , Yuchuan Bai","doi":"10.1016/j.geomorph.2024.109584","DOIUrl":"10.1016/j.geomorph.2024.109584","url":null,"abstract":"<div><div>Quantifying long-term morphological evolution of fluvial reach in river tail channels is crucial for floodplain management and ecological conservation in large river systems, yet remains challenging due to inherent complexities and uncertainties. This study introduces an integrated stochastic-data modeling framework to simulate the fluvial reach dynamics in the Yellow River tail channel, China. Stochastic differential equations (SDEs) incorporate white and correlated noise to capture stochastic responses of reach-averaged hydraulic geometry relationships governing channel changes. Gated recurrent unit (GRU) networks and gradient boosting machine algorithms extract signals from water-sediment data to forecast drivers like mean discharge and sediment load during the flood season. The models demonstrate strong performance, with the R<sup>2</sup> values for width, depth, and migration rate predictions reaching a maximum of 0.859, 0.445, and 0.540, respectively. The model experiments capture uncertainties and deliver probabilistic projections of future channel changes, with mean forecasts for this century indicating 50 % decrease in channel width, relatively stable depth (±5 % variation), and 80 % reduction in migration rate by 2100 relative to 2022 levels. While, integrated simulations with a channel centerline evolution model not only reveal significant and inescapable migration trends in the studied reach but also identify localized high-risk zones (e.g., the north-south migration of the river segments near the Qing 7 section could be up to 250 m in the future). Strategic interventions (dredging, fortifications, sediment replenishments) are recommended to balance navigability, habitability and ecological needs. The innovative methodology establishes foundations for advancing predictive process-based modeling of morphodynamic systems under climate shifts and anthropogenic stressors.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"472 ","pages":"Article 109584"},"PeriodicalIF":3.1,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161196","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-26DOI: 10.1016/j.geomorph.2024.109586
Shipei Dong , Zhuolun Li , Qiujie Chen , Yingyibing Shen , Xuehua Che , Cheng Zhang , Yinzhou Huang
Reconstructing wind activity strength enhances our understanding of desert evolution and environmental changes. Unmixing the grain-size components from eolian sands can serve as a proxy for wind activity in deserts. However, the links between the grain-size components of eolian sands and the strength of wind activity throughout the desert have rarely been explored. In this study, 81 surface eolian sand samples were analyzed from flat sandy areas or interdunes across the Tengger Desert in northwestern China, each with a similar depositional environment. The three grain-size components were separated from the samples using a parametric end-member mixing algorithm (EMMA). Based on their grain-size distribution characteristics, the three end-members (EMs) represent transport processes affected by various wind forces, including the East Asian winter monsoon (EAWM, EM1), local wind (EM2), and sandstorms (EM3). Additionally, the content of EM1 and the 63–158 μm components both showed significant positive correlations with EAWM indices, whereas the content of EM3 exhibited a significant negative correlation with the strong wind frequency (SWF). Therefore, these three new proxies (EM1, 63–158 μm components, and EM3) hold significant relationships with the wind activity indices, aiding in the quantitative reconstruction of paleo-wind activity strength in the drylands. This study enhances our understanding of the relationship between sedimentary proxies and wind activity strength, contributing to our knowledge of dryland eolian deposits and paleoenvironmental changes.
{"title":"Various wind activity proxies unmixed from grain-size distributions of surface eolian sands at the desert scale in the Tengger Desert, Northwest China","authors":"Shipei Dong , Zhuolun Li , Qiujie Chen , Yingyibing Shen , Xuehua Che , Cheng Zhang , Yinzhou Huang","doi":"10.1016/j.geomorph.2024.109586","DOIUrl":"10.1016/j.geomorph.2024.109586","url":null,"abstract":"<div><div>Reconstructing wind activity strength enhances our understanding of desert evolution and environmental changes. Unmixing the grain-size components from eolian sands can serve as a proxy for wind activity in deserts. However, the links between the grain-size components of eolian sands and the strength of wind activity throughout the desert have rarely been explored. In this study, 81 surface eolian sand samples were analyzed from flat sandy areas or interdunes across the Tengger Desert in northwestern China, each with a similar depositional environment. The three grain-size components were separated from the samples using a parametric end-member mixing algorithm (EMMA). Based on their grain-size distribution characteristics, the three end-members (EMs) represent transport processes affected by various wind forces, including the East Asian winter monsoon (EAWM, EM1), local wind (EM2), and sandstorms (EM3). Additionally, the content of EM1 and the 63–158 μm components both showed significant positive correlations with EAWM indices, whereas the content of EM3 exhibited a significant negative correlation with the strong wind frequency (SWF). Therefore, these three new proxies (EM1, 63–158 μm components, and EM3) hold significant relationships with the wind activity indices, aiding in the quantitative reconstruction of paleo-wind activity strength in the drylands. This study enhances our understanding of the relationship between sedimentary proxies and wind activity strength, contributing to our knowledge of dryland eolian deposits and paleoenvironmental changes.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"472 ","pages":"Article 109586"},"PeriodicalIF":3.1,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143161259","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-24DOI: 10.1016/j.geomorph.2024.109583
F. Pavano
Advancements in the quantitative investigation of fluvial topography in tectonically active regions account for the emerging numerical modelling of river profiles and their linear inversions. Applications of a geomorphic approach strive for the reconstruction of long-term tectonic deformation histories by decoding base-level fall signals transiently embedded in the geomorphic record. I present integrated results from river profile inversions and marine terraces analyses, here used to outline the deformation model associated to a debated crustal fault system at the southern termination of the Calabrian Forearc High (Central Mediterranean). The study aims at constraining spatial and temporal variations in geometry, strain partitioning, slip rate, and time-transgressive propagation of the tectonic deformation associated with a fault system. In particular, I systematically analyze river profiles draining the eastern flank of the Peloritani Mts. in northeastern Sicily (southern Italy), a NNE-SSW-trending mountain ridge thought as located at the footwall of an active, ESE-dipping normal fault. I perform the linear inversions of fluvial topography by applying recently available MATLAB scripts, and I carry out the analysis of terraced surfaces by both GIS tools and MATLAB-based software packages. The results I obtain suggest that the eastern flank of the Peloritani Mts. have been deformed according to at least three main stages of uplift accommodated along distinct, ∼10–15 km-long en-échelon arranged fault segments. The reconstructed evolution of tectonic deformation unveils time-transgressive, southward propagation since the last ∼600 kyr, inset in a general increase, through time, of the regional component of uplift. The results of this study contribute to address the issues of the deformation style and strain partitioning along complex and/or debated fault systems. These results also demonstrate the potential of the geomorphic approach in defining the spatial and temporal tectonic evolutionary model of a region.
{"title":"Fault geometry, strain partitioning and deformation history inferred by fluvial topography and marine terraces analyses","authors":"F. Pavano","doi":"10.1016/j.geomorph.2024.109583","DOIUrl":"10.1016/j.geomorph.2024.109583","url":null,"abstract":"<div><div>Advancements in the quantitative investigation of fluvial topography in tectonically active regions account for the emerging numerical modelling of river profiles and their linear inversions. Applications of a geomorphic approach strive for the reconstruction of long-term tectonic deformation histories by decoding base-level fall signals transiently embedded in the geomorphic record. I present integrated results from river profile inversions and marine terraces analyses, here used to outline the deformation model associated to a debated crustal fault system at the southern termination of the Calabrian Forearc High (Central Mediterranean). The study aims at constraining spatial and temporal variations in geometry, strain partitioning, slip rate, and time-transgressive propagation of the tectonic deformation associated with a fault system. In particular, I systematically analyze river profiles draining the eastern flank of the Peloritani Mts. in northeastern Sicily (southern Italy), a NNE-SSW-trending mountain ridge thought as located at the footwall of an active, ESE-dipping normal fault. I perform the linear inversions of fluvial topography by applying recently available MATLAB scripts, and I carry out the analysis of terraced surfaces by both GIS tools and MATLAB-based software packages. The results I obtain suggest that the eastern flank of the Peloritani Mts. have been deformed according to at least three main stages of uplift accommodated along distinct, ∼10–15 km-long <em>en-échelon</em> arranged fault segments. The reconstructed evolution of tectonic deformation unveils time-transgressive, southward propagation since the last ∼600 kyr, inset in a general increase, through time, of the regional component of uplift. The results of this study contribute to address the issues of the deformation style and strain partitioning along complex and/or debated fault systems. These results also demonstrate the potential of the geomorphic approach in defining the spatial and temporal tectonic evolutionary model of a region.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"472 ","pages":"Article 109583"},"PeriodicalIF":3.1,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143160709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A methodology to assess cultural georesources (CG) to promote tourism and leisure in a semiarid, steppe region of southern South America is presented. Two localities, Cabo Peñas at the coast, and Amalia shallow-lake inland, were analysed in terms of geodiversity, archaeological/historical record and recreational/tourist use. The methodological framework applied allows us to select, describe, hierarchize and validate CG among a list of several. The CG description includes the geological/geomorphological and cultural aspects as well as the available tourist infrastructure and equipment resulting from field work and surveys. The two CG herein presented are representative of different natural environments that were inhabited by native populations since the Middle Holocene times and nowadays have different level of accessibility and different degree of knowledge among the local people. A parametric assessment including the 3 analysed axes was contrasted to the perceptions of the key actors of the territory through a participative workshop. The hierarchization shows that Peñas cape is homogeneously ranked in the three axes while Amalia shallow-lake reveals that the geological/geomorphological and archaeological/historical axes are better valued than the recreational/tourist one. The validation step of the framework evidences the high interest the CG arouse among local people in order to visit and learn about them and a different level of identification towards them, that is, high for Peñas cape and low for Amalia shallow-lake, probably because of their distance to the city where these people live. The concept of CG offers the possibility to broaden the value of several geodiversity elements and gives relevance to the result of the human being's approach to the physical environment in the present times but also in the past. The methodology proposed to assess CG proved to be useful to reach an integral and deep analysis that takes into account scientific information and people's perceptions.
{"title":"Cultural georesources: Two study cases to promote tourism in the northern landscapes of Tierra del Fuego, Argentina","authors":"Soledad Schwarz , Andrea Coronato , Sabrina Labrone , Jimena Oría , Alejandro Montes , Federico Ponce , Ramiro López , Mónica Salemme","doi":"10.1016/j.geomorph.2024.109578","DOIUrl":"10.1016/j.geomorph.2024.109578","url":null,"abstract":"<div><div>A methodology to assess cultural georesources (CG) to promote tourism and leisure in a semiarid, steppe region of southern South America is presented. Two localities, Cabo Peñas at the coast, and Amalia shallow-lake inland, were analysed in terms of geodiversity, archaeological/historical record and recreational/tourist use. The methodological framework applied allows us to select, describe, hierarchize and validate CG among a list of several. The CG description includes the geological/geomorphological and cultural aspects as well as the available tourist infrastructure and equipment resulting from field work and surveys. The two CG herein presented are representative of different natural environments that were inhabited by native populations since the Middle Holocene times and nowadays have different level of accessibility and different degree of knowledge among the local people. A parametric assessment including the 3 analysed axes was contrasted to the perceptions of the key actors of the territory through a participative workshop. The hierarchization shows that Peñas cape is homogeneously ranked in the three axes while Amalia shallow-lake reveals that the geological/geomorphological and archaeological/historical axes are better valued than the recreational/tourist one. The validation step of the framework evidences the high interest the CG arouse among local people in order to visit and learn about them and a different level of identification towards them, that is, high for Peñas cape and low for Amalia shallow-lake, probably because of their distance to the city where these people live. The concept of CG offers the possibility to broaden the value of several geodiversity elements and gives relevance to the result of the human being's approach to the physical environment in the present times but also in the past. The methodology proposed to assess CG proved to be useful to reach an integral and deep analysis that takes into account scientific information and people's perceptions.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109578"},"PeriodicalIF":3.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134221","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1016/j.geomorph.2024.109579
Zigui Chen , Tao Jiang , Wenzhao Sun , Yue Chen , Cong Cheng , Ru Yin
Submarine canyons are important channels for sediment transportation in sloped areas and are key locations for the accumulation of gas hydrates and shallow gases. Understanding the evolution of submarine canyons and gas migration is crucial for natural gas exploration in the petroleum industry. In this study, we integrated bathymetric, seismic, logarithmic, and lithological data derived from slope-confined canyons in the Qiongdongnan Basin (QDNB) to examine their geomorphologies and filling patterns. This study has delved into the deposition processes, influencing factors, and evolutionary processes of these submarine canyons, as well as their relationship with gas hydrate accumulation. The results show five slope-confined submarine canyons in the study region, with water depths of 300–1700 m and NW-SE orientation. Canyon fills can be categorized into five types: turbidity-dominated muddy deposits, mass transport deposits, slumps, slides, and bottom current-dominated muddy deposits. These submarine canyons have developed from approximately 5.5 Ma and migrated toward the northeast. In addition, significant gas chimneys and bottom-simulating reflectors indicating gas hydrate accumulation were identified and were primarily located in the canyon ridge strata. Canyon evolution can be divided into three stages, with progression from turbidite channels to linear canyons, and eventually to dendritic canyons. The final evolutionary stage is closely linked to hydrate accumulation and decomposition. The canyon infillings controlled gas hydrate accumulation in the submarine canyon ridges. Gas hydrates located in the upper layer are prone to decomposition, promoting dendritic development of canyon walls. Gravity-flow activity through the evolution of slope-confined canyons is likely induced by factors such as high slope gradients, sea-level fluctuations, fault activity, hydrate decomposition, and earthquakes. The along-slope bottom currents reshaped the canyon landforms and facilitated their lateral migration.
{"title":"Origin and evolution of slope-confined canyons and their relationship with gas hydrate accumulation in the northwestern Qiongdongnan Basin, South China Sea","authors":"Zigui Chen , Tao Jiang , Wenzhao Sun , Yue Chen , Cong Cheng , Ru Yin","doi":"10.1016/j.geomorph.2024.109579","DOIUrl":"10.1016/j.geomorph.2024.109579","url":null,"abstract":"<div><div>Submarine canyons are important channels for sediment transportation in sloped areas and are key locations for the accumulation of gas hydrates and shallow gases. Understanding the evolution of submarine canyons and gas migration is crucial for natural gas exploration in the petroleum industry. In this study, we integrated bathymetric, seismic, logarithmic, and lithological data derived from slope-confined canyons in the Qiongdongnan Basin (QDNB) to examine their geomorphologies and filling patterns. This study has delved into the deposition processes, influencing factors, and evolutionary processes of these submarine canyons, as well as their relationship with gas hydrate accumulation. The results show five slope-confined submarine canyons in the study region, with water depths of 300–1700 m and NW-SE orientation. Canyon fills can be categorized into five types: turbidity-dominated muddy deposits, mass transport deposits, slumps, slides, and bottom current-dominated muddy deposits. These submarine canyons have developed from approximately 5.5 Ma and migrated toward the northeast. In addition, significant gas chimneys and bottom-simulating reflectors indicating gas hydrate accumulation were identified and were primarily located in the canyon ridge strata. Canyon evolution can be divided into three stages, with progression from turbidite channels to linear canyons, and eventually to dendritic canyons. The final evolutionary stage is closely linked to hydrate accumulation and decomposition. The canyon infillings controlled gas hydrate accumulation in the submarine canyon ridges. Gas hydrates located in the upper layer are prone to decomposition, promoting dendritic development of canyon walls. Gravity-flow activity through the evolution of slope-confined canyons is likely induced by factors such as high slope gradients, sea-level fluctuations, fault activity, hydrate decomposition, and earthquakes. The along-slope bottom currents reshaped the canyon landforms and facilitated their lateral migration.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109579"},"PeriodicalIF":3.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-16DOI: 10.1016/j.geomorph.2024.109582
Martina Burnelli , Alessia Pica , Maurizio Del Monte , Michele Delchiaro , Laura Melelli , Francesca Reame , Francesca Vergari , Massimiliano Alvioli
Urban geomorphology studies the landscape in cities, and changes induced by human activities to the natural landscape. Cities have different geological-geomorphological substrates, and humans as “geomorphic agents” have been operating within them in different times since the Paleolithic, threatening the Earth-surface heterogeneity and ecological sustainability, especially in urban areas. Urban geomorphology helps understanding natural and historical landscape evolution, changes to natural morphologies, and the effects of the development of cities on natural geomorphological processes. Quantitative geomorphodiversity describes the variety of landforms and morphological processes characterizing the landscape. Geomorphodiversity maps can be prepared using heterogeneous spatial data, at different geographical scales. Here, we adopt the land surface diversity index of Italy, which approximates field-based geomorphological maps. One relevant example of the latter, in Italy, is the geomorphological survey carried out in Rome, which integrates field surveys, historical maps, aerial photographs, archaeological and geomorphological literature. In this work, we compare the land surface diversity index, obtained with a simple and objective approach, with comprehensive geomorphological maps of locations describing the rural-urban gradient within the Rome urban area. We aim at understanding the representativeness of the geomorphodiversity index at the local scale, and its advantages and limitations, in urban areas. We describe a simple approach to compare the geomorphodiversity index and the geomorphological dataset. The method pins down to a common ground the five diversity classes, in the raster index, and the number of landforms mapped in the field, in the geomorphological map. Most notably, the latter distinguishes natural and anthropogenic landforms, allowing us a different assessment for these substantially different geomorphological elements. Results highlight that both natural and anthropogenic processes contribute to geomorphodiversity in urban environment, and in areas having different urbanization level. They are relevant to understand the anthropogenic morphogenesis impact on geomorphodiversity in urban environment.
{"title":"Does anthropogenic morphogenesis contribute to geomorphodiversity in urban environments?","authors":"Martina Burnelli , Alessia Pica , Maurizio Del Monte , Michele Delchiaro , Laura Melelli , Francesca Reame , Francesca Vergari , Massimiliano Alvioli","doi":"10.1016/j.geomorph.2024.109582","DOIUrl":"10.1016/j.geomorph.2024.109582","url":null,"abstract":"<div><div>Urban geomorphology studies the landscape in cities, and changes induced by human activities to the natural landscape. Cities have different geological-geomorphological substrates, and humans as “geomorphic agents” have been operating within them in different times since the Paleolithic, threatening the Earth-surface heterogeneity and ecological sustainability, especially in urban areas. Urban geomorphology helps understanding natural and historical landscape evolution, changes to natural morphologies, and the effects of the development of cities on natural geomorphological processes. Quantitative geomorphodiversity describes the variety of landforms and morphological processes characterizing the landscape. Geomorphodiversity maps can be prepared using heterogeneous spatial data, at different geographical scales. Here, we adopt the land surface diversity index of Italy, which approximates field-based geomorphological maps. One relevant example of the latter, in Italy, is the geomorphological survey carried out in Rome, which integrates field surveys, historical maps, aerial photographs, archaeological and geomorphological literature. In this work, we compare the land surface diversity index, obtained with a simple and objective approach, with comprehensive geomorphological maps of locations describing the rural-urban gradient within the Rome urban area. We aim at understanding the representativeness of the geomorphodiversity index at the local scale, and its advantages and limitations, in urban areas. We describe a simple approach to compare the geomorphodiversity index and the geomorphological dataset. The method pins down to a common ground the five diversity classes, in the raster index, and the number of landforms mapped in the field, in the geomorphological map. Most notably, the latter distinguishes natural and anthropogenic landforms, allowing us a different assessment for these substantially different geomorphological elements. Results highlight that both natural and anthropogenic processes contribute to geomorphodiversity in urban environment, and in areas having different urbanization level. They are relevant to understand the anthropogenic morphogenesis impact on geomorphodiversity in urban environment.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109582"},"PeriodicalIF":3.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134172","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Glacial lakes are prone to outburst due to breaching or overtopping of natural dams, leading to Glacial Lake Outburst Floods (GLOFs). These floods represent a substantial danger to communities downstream and essential infrastructure. To address this issue, it is crucial to investigate certain key factors, including gaining insight into the dynamics of glacial lakes, identifying dangerous ones, and assessing the associated level of risk. In this study, we scrutinized the temporal changes of glacial lakes in the Sikkim Himalaya for the years 1990, 2000, 2010, and 2020 using Landsat satellite imageries. Furthermore, we performed a hazard assessment of GLOFs in terms of both qualitatively, and quantitatively assessment. Moreover, qualitative evaluation involves seven external triggers and quantitative assessment employed by utilizing the Fuzzy Analytical Hierarchy Process (FAHP) method, considering six causative factors. Finally, we modelled the degree of risk associated with glacial lakes by quantifying downstream impacts with the help of GIS-based Stochastic Inundation Monte-Carlo Least Cost Path model (MC-LCP). The findings revealed that the number of glacial lakes increased from 309 to 440, with a total area expansion from 22.83 km2 to 30.71 km2 over the 30-year period. Also, among the 51 glacial lakes susceptible to GLOFs, seven lakes were classified as highly hazardous and another six were deemed to pose high risk. Overall this study contributes to planning field investigations and developing effective mitigation strategies to minimize the significant socio-economic losses caused by GLOFs in the Sikkim Himalaya.
{"title":"Hazard, and risk modelling of glacial lakes in the Sikkim Himalaya: Integrating qualitative and quantitative approaches for hazard assessment","authors":"Deepali Gaikwad , Reet Kamal Tiwari , Mahesh Kumar , Supratim Guha","doi":"10.1016/j.geomorph.2024.109577","DOIUrl":"10.1016/j.geomorph.2024.109577","url":null,"abstract":"<div><div>Glacial lakes are prone to outburst due to breaching or overtopping of natural dams, leading to Glacial Lake Outburst Floods (GLOFs). These floods represent a substantial danger to communities downstream and essential infrastructure. To address this issue, it is crucial to investigate certain key factors, including gaining insight into the dynamics of glacial lakes, identifying dangerous ones, and assessing the associated level of risk. In this study, we scrutinized the temporal changes of glacial lakes in the Sikkim Himalaya for the years 1990, 2000, 2010, and 2020 using Landsat satellite imageries. Furthermore, we performed a hazard assessment of GLOFs in terms of both qualitatively, and quantitatively assessment. Moreover, qualitative evaluation involves seven external triggers and quantitative assessment employed by utilizing the Fuzzy Analytical Hierarchy Process (FAHP) method, considering six causative factors. Finally, we modelled the degree of risk associated with glacial lakes by quantifying downstream impacts with the help of GIS-based Stochastic Inundation Monte-Carlo Least Cost Path model (MC-LCP). The findings revealed that the number of glacial lakes increased from 309 to 440, with a total area expansion from 22.83 km<sup>2</sup> to 30.71 km<sup>2</sup> over the 30-year period. Also, among the 51 glacial lakes susceptible to GLOFs, seven lakes were classified as highly hazardous and another six were deemed to pose high risk. Overall this study contributes to planning field investigations and developing effective mitigation strategies to minimize the significant socio-economic losses caused by GLOFs in the Sikkim Himalaya.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109577"},"PeriodicalIF":3.1,"publicationDate":"2024-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-15DOI: 10.1016/j.geomorph.2024.109581
Fan Wu , Chaowei Jiang , Chao Wang , Lichuan Zou , Tianyang Li , Shaoyang Guan , Yixian Tang
Due to permafrost degradation, retrogressive thaw slumps (RTSs) have increasingly occurred in the past decade, altering landscape patterns and ecological environments in permafrost regions while accelerating soil carbon emissions. This study introduces a framework for RTS recognition and occurrence analysis based on deep learning and change analysis techniques. We propose a hybrid convolution and transformer neural network (HCT-Net) to recognize RTSs automatically. The network employs Synthetic Aperture Radar (SAR) and optical imagery for RTS detection. To effectively integrate the feature extraction capabilities of Convolutional Neural Network (CNN) and Vision Transformer (ViT), a Cross Feature Fusion Module (CFFM) has been developed. With the generated RTS map, Landsat series satellite images spanning from 2001 to 2023 were acquired for long-term observation and analysis of RTSs evolution. The occurrence years of detected RTSs were estimated employing the LandTrendr model, enabling a year-to-year dynamics analysis of RTS development. Focusing on the central Qinghai-Tibet Plateau (QTP), including the Beiluhe basin, Hoh Xil Hill, and Mt. Fenghuo area, covering approximately 49,000 km2, experiments have been conducted for RTS recognition and multi-temporal analysis. Results demonstrate that the proposed method achieves an Intersection over Union (IOU) and F1 score of 72.95 % and 88.30 % for RTS recognition, outperforming other semantic segmentation methods such as Deeplabv3+, Segformer, UNet, and Swin-UNet. Based on the RTSs detected within the study area during 2001–2023, the occurrence year of the RTSs was estimated. The findings reveal a continuous expansion of RTSs since 2001 and confirm concentrated outbreaks in the years 2010 and 2016. The proposed framework offers a good approach for RTSs recognition and analysis, which can support further research into permafrost degradation.
{"title":"Retrogressive thaw slumps recognition and occurrence analysis using deep learning with satellite remote sensing in the central Qinghai-Tibet Plateau","authors":"Fan Wu , Chaowei Jiang , Chao Wang , Lichuan Zou , Tianyang Li , Shaoyang Guan , Yixian Tang","doi":"10.1016/j.geomorph.2024.109581","DOIUrl":"10.1016/j.geomorph.2024.109581","url":null,"abstract":"<div><div>Due to permafrost degradation, retrogressive thaw slumps (RTSs) have increasingly occurred in the past decade, altering landscape patterns and ecological environments in permafrost regions while accelerating soil carbon emissions. This study introduces a framework for RTS recognition and occurrence analysis based on deep learning and change analysis techniques. We propose a hybrid convolution and transformer neural network (HCT-Net) to recognize RTSs automatically. The network employs Synthetic Aperture Radar (SAR) and optical imagery for RTS detection. To effectively integrate the feature extraction capabilities of Convolutional Neural Network (CNN) and Vision Transformer (ViT), a Cross Feature Fusion Module (CFFM) has been developed. With the generated RTS map, Landsat series satellite images spanning from 2001 to 2023 were acquired for long-term observation and analysis of RTSs evolution. The occurrence years of detected RTSs were estimated employing the LandTrendr model, enabling a year-to-year dynamics analysis of RTS development. Focusing on the central Qinghai-Tibet Plateau (QTP), including the Beiluhe basin, Hoh Xil Hill, and Mt. Fenghuo area, covering approximately 49,000 km<sup>2</sup>, experiments have been conducted for RTS recognition and multi-temporal analysis. Results demonstrate that the proposed method achieves an Intersection over Union (IOU) and F1 score of 72.95 % and 88.30 % for RTS recognition, outperforming other semantic segmentation methods such as Deeplabv3+, Segformer, UNet, and Swin-UNet. Based on the RTSs detected within the study area during 2001–2023, the occurrence year of the RTSs was estimated. The findings reveal a continuous expansion of RTSs since 2001 and confirm concentrated outbreaks in the years 2010 and 2016. The proposed framework offers a good approach for RTSs recognition and analysis, which can support further research into permafrost degradation.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109581"},"PeriodicalIF":3.1,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134155","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-12-15DOI: 10.1016/j.geomorph.2024.109574
Aditi Roy , Priyank Pravin Patel , Anjan Sen
The Brahmani River basin in eastern India exhibits marked influence of tectonic and litho-structural control in its incised stream reaches, sharp changes in channel direction and the presence of numerous structural discontinuities. The combined effect of these attributes in shaping the basin geomorphology and landscape character are analysed through detailed morphometric evaluation at the sub-watershed level, overlaying lithological and geomorphic units on relevant terrain parameters extracted from Copernicus-DEM tiles and ancillary map information. Alongside this, we also analyse the longitudinal profile character of the principal stream and its main tributaries to discern knickpoints and their locations in terms of rock types and their possible origins, discerning that these are mostly situated in granitic and quartzite terrain and at elevations above 300 m. Higher values of stream gradient (SL) index indicate regional uplift, and possibly tectonically affected areas, often near vertical knickpoints along fault zones in varying litho-structural units. Computed Chi (χ) plots suggest zones of river capture and drainage divide migration, with χ values decreasing from north to south across the basin and sub-watershed divides shifting towards northwest for the Lawa river, north-eastwards for the Sankh, South Koel and North Karo rivers, and towards southeast for the South Karo river. The probable paleo-surfaces and paleo-profiles of these streams is also reconstructed, based on their present longitudinal elevation and overall uplift extents from m.s.l. are estimated (~540 m uplift and ~45 m uplift in the upper and lower basin zones, respectively). Our analysis makes it evident that most channel segments are not in an equilibrium phase, thus denoting the continued influence of structural and possible latter-day tectonic movements (as evidenced by recent local seismic activity), through reactivation of the crustal-scale basement faults, shear zones and mobile belts that lie astride and across the Brahmani Basin in the Eastern Ghats hills.
{"title":"Unravelling litho-structural and tectonic influences on geomorphic and river longitudinal profile character in the Brahmani River Basin of eastern India","authors":"Aditi Roy , Priyank Pravin Patel , Anjan Sen","doi":"10.1016/j.geomorph.2024.109574","DOIUrl":"10.1016/j.geomorph.2024.109574","url":null,"abstract":"<div><div>The Brahmani River basin in eastern India exhibits marked influence of tectonic and litho-structural control in its incised stream reaches, sharp changes in channel direction and the presence of numerous structural discontinuities. The combined effect of these attributes in shaping the basin geomorphology and landscape character are analysed through detailed morphometric evaluation at the sub-watershed level, overlaying lithological and geomorphic units on relevant terrain parameters extracted from Copernicus-DEM tiles and ancillary map information. Alongside this, we also analyse the longitudinal profile character of the principal stream and its main tributaries to discern knickpoints and their locations in terms of rock types and their possible origins, discerning that these are mostly situated in granitic and quartzite terrain and at elevations above 300 m. Higher values of stream gradient (SL) index indicate regional uplift, and possibly tectonically affected areas, often near vertical knickpoints along fault zones in varying litho-structural units. Computed Chi (χ) plots suggest zones of river capture and drainage divide migration, with χ values decreasing from north to south across the basin and sub-watershed divides shifting towards northwest for the Lawa river, north-eastwards for the Sankh, South Koel and North Karo rivers, and towards southeast for the South Karo river. The probable paleo-surfaces and paleo-profiles of these streams is also reconstructed, based on their present longitudinal elevation and overall uplift extents from m.s.l. are estimated (~540 m uplift and ~45 m uplift in the upper and lower basin zones, respectively). Our analysis makes it evident that most channel segments are not in an equilibrium phase, thus denoting the continued influence of structural and possible latter-day tectonic movements (as evidenced by recent local seismic activity), through reactivation of the crustal-scale basement faults, shear zones and mobile belts that lie astride and across the Brahmani Basin in the Eastern Ghats hills.</div></div>","PeriodicalId":55115,"journal":{"name":"Geomorphology","volume":"471 ","pages":"Article 109574"},"PeriodicalIF":3.1,"publicationDate":"2024-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143134157","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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