Geomorphology最新文献

200 years of coupled relief disturbance in the heart of a former industrial city

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-11-28 DOI: 10.1016/j.geomorph.2024.109537

Jan Lenart , Martin Kašing , Kristýna Schuchová , Radek Tichavský

Landscapes in industrialized areas undergo distinct stress due to numerous and rapid changes, including geomorphic disturbances. We investigated a distinct abandoned sloped area above the river channel in the heart of an industrial city with a population of 300,000 inhabitants. Traces of numerous past changes enabled us to reconstruct a narrative of coupled and chained disturbances spanning over 200 years. Ten different landscape-forming processes of natural, mining, urban, and war origins were identified and dated through field mapping, dendrogeomorphic and geophysical surveys, speleological exploration, and analysis of historical maps and reports. The most impactful processes included slope retreat, structural landslides, stone quarrying, and ground subsidence induced by coal mining, while rockfalls, urbanization, and war disruptions had lesser effects. The collapse of an air-raid shelter, combined with other processes, created a remarkable cave exposing coal seams. These identified processes interact within a complex environment, either immediately or with time gaps of tens or even hundreds of years. The responses of relief and landscape to these events were captured in discernible relief generations. The derelict landscape, composed of numerous spatial units resulting from many temporal events, is unique—a landscape devastated and yet valuable. We discuss two potential scenarios for the site's future development: gradual erasure of past relief generations leading to landscape homogenization, or the occurrence of further disturbances increasing the complexity of the palimpsest.

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引用次数: 0

Physically-based digital geomorphological mapping: Case study of glacial and karst topography

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-11-28 DOI: 10.1016/j.geomorph.2024.109539

Anton B. Popov , Jozef Minár , Lucian Drǎguţ

Digital geomorphological mapping is considered here as a semi-automated procedure of division the land surface into genetically meaningful objects. The basis is automatic segmentation into elementary forms, the smallest and indivisible elements of the land surface, should be geometrically clearly identifiable, with maximal internal homogeneity and clear discontinuities at their boundaries. These elements can then be combined into more complex genetically homogeneous composite forms. Given the crucial role of gravitational energy in landform formation, it should also be considered in elementary land surface segmentation . This research builds on the theoretical foundation of physical geomorphometry, which explores the relationship between gravitational energy and geomorphometric variables. Specifically, we apply the recently published algorithm for physically-based elementary land surface segmentation by Minár et al. (2024), which utilizes dynamic least squares (DLS) generalization within a GEOBIA framework. The algorithm was initially tested in structurally fluvial hilly terrain using nine physically interpretable gravity-specific point-based variables (elevation, slope aspect and gradient, three basic curvatures, and three changes in curvature). In this study, we extend the application of this algorithm to two different areas of the Western Carpathians: the glacial topography of its highest part and a karst plateau. By using a slightly simplified and specifically modified version of the physically-based algorithm, we achieved plausible and genetically interpretable results in both case studies, which confirms the value of physical geomorphometry in geomorphological mapping. Additionally, a novel concept of physical-geomorphometric signature was applied in both case studies as a support for the physical-geomorphometric analysis. The physical-geomorphometric signature is very helpful in the quantitative comparison between various genetic groups of landforms.

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引用次数: 0

Episodic rainfall events characterise complex sediment deposition in a fault-bounded sag pond in Northwest China

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-11-28 DOI: 10.1016/j.geomorph.2024.109538

Chris Gouramanis , Stephen Chua , Marie Etchebes , Yann Klinger , Xiwei Xu , Gao Mingxing , Adam D. Switzer , Gary Hancock , Paul Tapponnier

Fault-bounded sag pond sediment records are commonly found to be excellent archives of palaeoearthquakes and more rarely, they can provide robust evidence of local environment and climate change. We examined the sedimentary and geomorphological record of the Aksay Pond within the Karachingar Valley along the southern margin of the Altai Mountain Range in northwestern China. This pond is associated to a shutter ridge resulting from cumulative deformation associated with successive earthquakes along the Fuyun Fault, including the most recent 11 August 1931 M_w7.9 earthquake. However, detailed chronology based on ¹⁴C Accelerator Mass Spectrometry, ²¹⁰Pb and ¹³⁷Cs dating suggests that only deformation related to the 1931 earthquake have been preserved at the pond site. A small wedge of sediments comprising cobble and gravel sized clasts are separated by two palaeosoil deposits suggesting that very minor sediment could accumulate prior to 1931. In the northern part of the pond, sediment was deposited predominantly from a colluvial fan that has periodically been mobilised from the steep mountain slopes to the east. In the southern part of the pond we find that the dry climate of the region has experienced periodic storms that have resulted in the deposition of 11 fining upwards packages formed by remobilised and deposited sand to mud-sized sediments within the pond. Associated with these fining upward cycles are two colluvial wedges that emanate from the fault scarp. The upper wedge is dated at approximately 1986 CE and coincides with a high precipitation event recorded at the Fuyun Meteorological Station in 1986. The middle wedge may be related to an earlier high precipitation event, but due to challenges in obtaining accurate ages, cannot be verified. Alternatively, these two colluvial wedges could coincide with minor ca. M_w5 earthquakes in the region. Importantly, these wedges are not associated with large scale rupturing similar to the 1931 earthquake. Based on the sedimentary and geomorphological evidence of the Aksay Pond, we propose a model for the sequential formation of sag ponds highlighting the influence of both climatic and tectonics processes.

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引用次数: 0

Intensified susceptibility to riverbed incisions under sand mining impacts in the Vietnamese Mekong Delta: A long-term spatiotemporal analysis

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-11-27 DOI: 10.1016/j.geomorph.2024.109535

Menna Farag Ahmed , Doan Van Binh , Sameh Ahmed Kantoush , Edward Park , Nguyen Luyen Phuong Doan , Luc Anh Tuan , Vuong Nguyen Dinh , Thi Huong Vu , Binh Quang Nguyen , Trieu Anh Ngoc , Nguyen Xuan Tung , Tetsuya Sumi

The Vietnamese Mekong Delta (VMD) has experienced severe morphological changes for decades, resulting in serious social, economic, and environmental consequences. Several natural and anthropogenic factors have contributed to the increasing rate of riverbed incision along the VMD. While previous studies have assessed riverbed incisions in specific affected regions or within limited timeframes, a comprehensive analysis of long-term spatiotemporal variations in incised sediment volumes across the entire delta has been lacking. This study quantitatively evaluated the spatial and temporal morphological changes in the VMD utilizing bathymetric data from 1998 to 2020. Additionally, susceptibility zones, categorized into seven classes for incised and accreted sediment volumes, were delineated considering the influence of sand mining activities. Furthermore, this study pioneers the quantification of sand mining contributions to riverbed incisions along the VMD. The analysis revealed pronounced and irregular morphological alterations in the delta channels over the 22 years of the study. The estimated net annual incision volumes for the entire region were -119 Mm³/year, −69 Mm³/year, and -66 Mm³/year for the 1998–2005, 2005–2017, and 2017–2020 time intervals, respectively. Between 2017 and 2020, the dynamic processes intensified notably, with some areas experiencing either high incision (up to −13 m/year) or high accretion (up to 11 m/year). Intriguingly, most incise-prone areas were partly situated within regions associated with sand mining. The contribution of licensed sand mining to annual net riverbed incisions increased from 27.7 % in 2005–2017 to 35.3 % in 2017–2020. This study highlights the influence of sand mining on exacerbating the vulnerability of different areas within the VMD and provides valuable insights for effective sediment management strategies.

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引用次数: 0

Inventory and assessment of geosites to promote geotourism in Coto Brus, Costa Rica

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-11-26 DOI: 10.1016/j.geomorph.2024.109531

Michael Quesada-Valverde, Adolfo Quesada-Román

This study constitutes a pioneering inventory of geosites and an assessment of Coto Brus, Costa Rica. In collaboration with the Municipality of Coto Brus, we generated baseline knowledge of the existing geosites from this area to support the creation of a touristic route, within the framework of the project One Village, One Product (OVOP), hereinafter OVOP Coto Brus. The slogan of the project is “We are Coto Brus, a paradise Discover us!” The project seeks the economic growth in a region that has been historically dependent on cattle and agriculture. The study reveals the geodiversity of Coto Brus, providing a paleogeographic perspective. On the one hand, it is based on the demonstrated role of geotourism for the socioeconomic development of local economies that adopt it. On the other hand, it contributes to the Sustainable Development Goals (SDG) of the region. Key geosites identified for geotourism include waterfalls such as El Ángel and Santa Fe, the hills of Cerro Pelón and Cerro Quijada del Diablo, and the thermal waters of Aguas Calientes. In addition, the Laguna Zoncho stands out as a lagoon with paleoecological, paleoclimatological, and archaeological importance in ecologically rich sites such as the San Vito Wetland, La Caverna Barranquilla, Cerros Gemelo, and Pittier. They constitute unique opportunities for bird and wildlife observation. Finally, the study recommends that the Municipality of Coto Brus and the stakeholders in the OVOP Coto Brus project implement geosite management plans in the formulation of the touristic route, emphasizing the community's commitment to guarantee sustainable tourism and geoconservation.

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引用次数: 0

Washover fan deposits resulting from perigean spring tides: An example from Cape Cod, Massachusetts, USA

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-11-26 DOI: 10.1016/j.geomorph.2024.109536

Katherine A. Castagno , Eliza J. Fitzgerald , Kaitlyn Button , Petra Zuñiga , Tommy Tucker , Timothy Smith , Mark Borrelli

In early 2021, the dune at Duck Harbor Beach (Wellfleet, MA, USA) was overtopped by high water levels, forming a washover fan that continues to grow through persistent overwash events. Overwash events occur near-monthly on most spring tides, regardless of weather, and have occurred for nearly four years. This is unique because the vast majority of washover fans occur because of storms and generally build in elevation requiring increasing water levels for overwash to occur. The overwash has salt-killed ~48.5 ha of trees and shrubs, and the system has begun to transition from freshwater to saltwater. We document the development of this tidal washover fan, including a detailed examination of changes in elevation and grain size during the early January 2022 events. Understanding how this system has developed will inform our understanding of the fate of other low-lying coastal areas, which are growing increasingly vulnerable to the effects of sea-level rise and ecosystem change.

引用次数: 0

Spatial distribution and transport characteristics of debris flow sediment using high resolution UAV images in the Ohya debris flow fan 利用高分辨率无人机图像分析大屋泥石流扇区泥石流沉积物的空间分布和迁移特征

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-11-25 DOI: 10.1016/j.geomorph.2024.109533

Saleh Yousefi , Fumitoshi Imaizumi , Shoki Takayama

Debris flows are significant geomorphic processes that can pose hazards to human settlements and infrastructure, making the understanding of their sediment transfer characteristics and impacts on the surrounding landscape crucial for effective land management and hazard mitigation strategies. This study investigates the distribution patterns of sandstone, vegetation, and shale classes within the Ohya debris flow fan, aiming to gain insights into the sediment characteristics, grain size variations, and vegetation cover trends along the flow path. Using a combination of field surveys and image processing we analyzed sediment characteristics and grain size variations a three study zones: upstream, transfer, and downstream. Statistical parameters such as mean, mode, skewness, and kurtosis were employed to quantify the grain size distribution and identify variations across the study zones. Results reveal distinct spatial variations in the distribution of sandstone, vegetation, and shale classes along the flow path. We observed a decrease in sandstone and vegetation cover from the upstream to the downstream sections, while the area covered by the shale class exhibited an increasing trend in the downstream direction. These findings suggest that debris flows selectively remove smaller particles downstream. The distribution of particle sizes within the sandstone class also exhibited variations, with a higher proportion of smaller pebbles downstream due to more effective removal of finer particles in the upstream zone. This study highlights the complex interplay between debris flow dynamics, sediment transport, and vegetation colonization. The findings contribute to the scientific knowledge of debris flow processes and can be used to inform land management decisions and mitigate the hazards associated with debris flows in similar environments.

泥石流是一种重要的地貌过程，可对人类住区和基础设施造成危害，因此了解泥石流的沉积物转移特征及其对周围景观的影响对于有效的土地管理和减灾战略至关重要。本研究调查了 Ohya 泥石流扇区内砂岩、植被和页岩类别的分布模式，旨在深入了解流道沿线的沉积物特征、粒度变化和植被覆盖趋势。通过实地勘测和图像处理相结合的方法，我们分析了上游、中游和下游三个研究区的沉积物特征和粒度变化。我们采用了平均值、模式、偏度和峰度等统计参数来量化粒度分布，并确定各研究区的变化情况。结果显示，砂岩、植被和页岩类别的分布沿水流路径存在明显的空间变化。我们观察到砂岩和植被的覆盖面积从上游到下游呈下降趋势，而页岩类覆盖面积在下游方向呈上升趋势。这些发现表明，泥石流会选择性地将较小的颗粒清除到下游。砂岩类中颗粒大小的分布也呈现出变化，由于上游区域更有效地清除了较细的颗粒，因此下游较小的卵石所占比例较高。这项研究强调了泥石流动力学、沉积物迁移和植被定植之间复杂的相互作用。研究结果有助于增进对泥石流过程的科学认识，并可为土地管理决策提供依据，减轻泥石流在类似环境中造成的危害。

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引用次数: 0

Toward flow forces acting on a step-pool unit 作用在阶梯池单元上的流向力

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-11-22 DOI: 10.1016/j.geomorph.2024.109523

Chendi Zhang , Marwan A. Hassan , Yuncheng Xu

The flow forces on step-pool units are important to understand the physical processes and flow resistance partitioning in step-pool channels, and build the basis for better prediction of channel evolution and more advanced design of artificial step-pool system. However, the flow forces acting on step-pool units are understudied and poorly understood. To fill this knowledge gap, we applied the approach combining physical experiment and computational fluid dynamics simulation to a step-pool unit made of natural grains at six flow conditions. The topography of the step-pool unit was split into topography components (TCs) covering the entire unit length with the same width. The flow forces from both pressure and shear stress in XYZ directions were examined for the TCs. The results illustrate significant transverse variability of the flow forces from both the shear stress and pressure at all the three directions. The flow forces in both X and Y directions are closely related to the flow structures and morphology in the unit. The ratios between skin and form drag have large variations at low flows while show a relatively limited range of 0.05–0.1 at high flows, suggesting a small proportion occupied by the skin resistance in the total flow resistance in the step-pool channel. The drag and lift coefficient generally increase with discharge and the drag coefficient of the unit is around 0.3 at high flows, which can be used in evaluating the stability of the step-pool units in a sequence.

台阶水池单元上的流动力对于了解台阶水池渠道的物理过程和流动阻力分区非常重要，可为更好地预测渠道演变和更先进的人工台阶水池系统设计奠定基础。然而，人们对作用于台阶池单元的流力研究不足，了解甚少。为了填补这一知识空白，我们采用物理实验和计算流体动力学模拟相结合的方法，在六种流动条件下对天然谷物制成的阶梯池单元进行了研究。阶梯池单元的地形被分割成覆盖整个单元长度且宽度相同的地形组件（TC）。研究了这些 TC 在 XYZ 方向上的压力和剪应力流动力。结果表明，在所有三个方向上，来自剪应力和压力的流动力都存在明显的横向变化。X 和 Y 方向的流力与单元内的流动结构和形态密切相关。在低流量时，表皮阻力和形态阻力的比值变化很大，而在高流量时，比值范围相对有限，仅为 0.05-0.1，这表明表皮阻力在阶梯池水道的总流阻中所占比例很小。阻力系数和升力系数一般随排水量的增加而增大，大流量时单元的阻力系数约为 0.3，可用于评价梯级水池单元的稳定性。

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引用次数: 0

Evolution of coastal transgressive aeolian sand sheets over 75 years (1948-2023) at Concheiros Barrier - Southern Brazilian coast

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-11-22 DOI: 10.1016/j.geomorph.2024.109520

Débora S.Z. Watanabe , Eduardo G. Barboza-Pinzon , Patrick A. Hesp , Venisse Schossler , Eduardo T. Salgado

Transgressive sand sheets (TSS) and transgressive dunefields (TDf) over time often present multiple phases of development and various morphologies controlled by biogeomorphological interactions related to abiotic processes, vegetation, and human interference. While dunefields have experienced increased vegetation cover over the last decades worldwide, a few places have shown increased dune mobility. In this study, a GIS analysis was conducted using aerial photographs and satellite imagery to investigate the evolution of a TDf, foredune collapse, new TSS formation, and vegetation cover on a Holocene coastal barrier in southern Brazil over the last 75 years (from 1948 to 2023). Wind speed (1994–2009), significant wave height (Hs) and peak wave period (Tp) (1940–2022) were analyzed to examine these potential drivers that could have caused geomorphological changes on the foredunes and dune system. Vegetation cover exhibited an increasing trend, and both an increase and decrease in TDf movement and TSS expansion were concurrent. Correlation analyses revealed a strong negative correlation between vegetation cover and TDf movement. Three transgressive sand sheet formation phases were identified between 1948 and 2023 (1964 to 1975,1996 to 2000, and from 2010 until 2023). Post-2003, a poorly vegetated nebkha-dominated foredune subsequently collapsed and was replaced by a TSS in less than a decade, being fully formed in 2010 and continuing to move inland at rapid rates. In the third phase, the highest total TSS expansion exceeded 700 m in 12 years (from 2010 to 2022). A small increase in wind velocity and subsequent decrease may possibly have contributed to the formation of the TSS second phase and the foredunes respectively. Other possible drivers for TSS formation include climatic modes, negative precipitation anomalies and groundwater level lowering, in addition to anthropogenic actions (especially water extraction) that might have caused a negative feedback in foredune sand-biding vegetation.

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引用次数: 0

Assessment of soil erosion by RUSLE in the Ecuadorian basins (2001−2020) based on GIS and high-resolution satellite data: Main drivers and changes on soil erosion 以地理信息系统和高分辨率卫星数据为基础，通过 RUSLE 评估厄瓜多尔流域（2001-2020 年）的土壤侵蚀情况：土壤侵蚀的主要驱动因素和变化

IF 3.1 2区地球科学 Q2 GEOGRAPHY, PHYSICAL

Geomorphology

Pub Date : 2024-11-22 DOI: 10.1016/j.geomorph.2024.109515

Daniel Delgado , Mahrez Sadaoui , Wolfgang Ludwig , Williams Méndez , Eduardo Ortiz-Hernández , Pablo Farfán-Intriago

Soil erosion is a significant environmental problem that can have devastating impacts on ecosystems and the sustainability of agricultural lands, including landscape degradation and biodiversity loss. Estimating erosion rates requires the installation of measurement devices such as sediment traps and runoff collectors or the use of erosion plots considering soil texture and vegetation cover. However, these procedures have significant spatial and temporal limitations, in addition to high implementation costs. The objective of this study was to analyze soil erosion in Ecuadorian basins using the Revised Universal Soil Loss Equation (RUSLE) based on Geographic Information System (GIS) and high-resolution satellite data from 2001 to 2020. The methodology involved delineating and evaluating the environmental characteristics of Ecuadorian basins, precipitation data, soil physical and chemical properties, identification of the Normalized Difference Vegetation Index (NDVI), land use, Digital Elevation Model (DEM) selection and assigning values based on slope raster. Basin delineation was obtained from regional literature; precipitation data from GPM-IMERG web servers; sand, clay, silt, and Soil Organic Carbon (SOC) content from SoilGrids web servers; DEM from SRTM database; spatial-temporal distribution of NDVI and land use from MODIS database; and P Factor value ranges based on slope from global literature. Recorded erosion rates ranged from 0.28 t/ha year to 2373.85 t/ha year, with the highest values identified in the Andes Mountains due to steep slopes. The main driver of soil erosion in Ecuadorian basins was the R-Factor, followed by LS and C. Land use variations indicated a loss of 9771 km² of forests and 80 km² of cultivated lands between 2001 and 2020, while semi-natural vegetation increased by 9851 km². These results provide relevant information to assist land managers in making decisions to address this natural phenomenon.

土壤侵蚀是一个严重的环境问题，会对生态系统和农业用地的可持续性造成破坏性影响，包括景观退化和生物多样性丧失。估算水土流失率需要安装沉积物收集器和径流收集器等测量装置，或使用考虑到土壤质地和植被覆盖的侵蚀地块。然而，这些方法除了实施成本高昂外，还存在很大的空间和时间限制。本研究的目的是根据地理信息系统 (GIS) 和 2001 年至 2020 年的高分辨率卫星数据，使用修订的通用土壤流失方程 (RUSLE) 分析厄瓜多尔流域的土壤侵蚀情况。该方法涉及厄瓜多尔盆地环境特征的划分和评估、降水数据、土壤物理和化学特性、归一化植被指数（NDVI）的确定、土地利用、数字高程模型（DEM）的选择以及基于坡度栅格的赋值。流域划分来自区域文献；降水数据来自 GPM-IMERG 网络服务器；沙、粘土、粉土和土壤有机碳 (SOC) 含量来自 SoilGrids 网络服务器；DEM 来自 SRTM 数据库；归一化差异植被指数 (NDVI) 的时空分布和土地利用情况来自 MODIS 数据库；基于坡度的 P 因子值范围来自全球文献。记录的侵蚀率从 0.28 吨/公顷/年到 2373.85 吨/公顷/年不等，其中安第斯山脉的陡坡侵蚀率最高。土地利用的变化表明，2001 年至 2020 年期间，森林面积减少了 9771 平方公里，耕地面积减少了 80 平方公里，而半自然植被面积增加了 9851 平方公里。这些结果提供了相关信息，有助于土地管理者做出应对这一自然现象的决策。

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引用次数: 0