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The outer bank slump blocks play a fundamental role in modulating the rate of bank erosion, and consequently, have a profound influence on many geomorphic and ecologic processes in meandering streams, e.g., channel evolution and habitat creation. To date, no adequate research has been developed regarding how these blocks, partially strengthened by roots of herbaceous plants, impact the near-bank flow velocity, bank erosion, and migration of streambanks. This paper analyzes 246 slump blocks in a meandering stream on the Marqu Meadow, China. Aerial surveys were conducted once a year from 2018 to 2021 and the lateral migration rates (M) of streambanks are estimated by superimposing the current-year drone imagery onto its previous-year counterpart. When compared to the outer bank segments lacking slumps, our research findings indicate that the bank segments exhibiting slumps demonstrate a reduction of 57 % and 43 % in the maximum and average bank erosion rates, respectively. Overall, the wider blocks provide stronger bank protection; nevertheless, they may also introduce or enhance local scouring in their vicinity, thereby increasing the heterogeneity of bank erosion rates. To elucidate this complex influence mechanism, we simulate the three-dimensional flow velocity field of a ~100 m meandering bend containing three slump blocks using the MIKE-3 model. Furthermore, we compare one-year bank migration distance with and without the blocks by correlating the lateral migration distance of outer banks to the longitudinal gradient of near-bank velocity. The paper provides valuable insights into the complex interplay between flow dynamics and streambank behavior in real-world settings, thereby enhancing the effectiveness of future management and restoration practices. • 246 slump blocks were analyzed in a meander on Marqu Meadow, China. • Slump blocks can persist for years but may be washed away in high flows. • The outer bank slump blocks play a vital role in modulating bank erosion rates. • Slump blocks protect outer banks by redistributing the high flow and secondary flow. • Slump blocks help protect bank overall but it may introduce scour in their vicinity. [ABSTRACT FROM AUTHOR]

Creeks are essential for salt marshes by conveying water and sediment through this geomorphic system. In this paper, we investigate the mechanisms that determine the residual sediment flux using measurements conducted in tidal creeks in salt marshes of the Yangtze Estuary. A main creek and a secondary creek were studied to explore whether the mechanisms determining residual sediment fluxes through the main creek differ from those in the secondary creek. Measurements in creeks were carried out over 5 years, spanning different months. Sediment import was found during most tides, both in the main creek and the secondary creek, implying that creeks in Chongming generally function as a conveyor belt of sediment into the marsh. However, sediment export can occur during certain overbank tides. When comparing the role of creeks in drainage and sediment delivery, the main creek functions more in delivering sediment while the secondary creek primarily serves as a drainage conduit. To better understand the mechanisms behind sediment fluxes, the residual sediment flux was compared with the residual discharge and the sediment differential (differences in sediment concentration between flood and ebb). Overbank tides generally lead to a net outward discharge as more water from saltmarshes can be concentrated into the marsh creek during ebb tides. This net outward discharge tends to export more sediment during ebb tides. However, due to the sediment abundance during the flood phase in the turbid environment, sediment import can be expected even with the residual export of water. Export of sediment was only found for the few tides with a net outward discharge and a small positive sediment concentration differential. Large negative sediment differentials (larger averaged suspended sediment concentration during ebb tides) have not been observed because the sediment supply during ebb is limited. This paper unravels how the sediment differential and residual discharge contribute to the residual sediment flux, providing a better understanding of sediment dynamics in marsh creek systems. • The relative importance of asymmetries in sediment concentration and in flow for residual sediment fluxes was explored. • The main creek is mainly a conduit for sediment delivery whereas the secondary creek is mainly a drainage conduit. • Sediment supply limitation can even occur in a turbid system like Chongming. [ABSTRACT FROM AUTHOR]

The common morphologies of slope surfaces in nature include linear, stepped, convex, concave, and their combination types. Many researchers have investigated the stability of slopes with simple linear, stepped convex, or concave geometric morphologies, disregarding the effect of combination of convex and concave morphology. In this paper, slope surfaces with convex-concave characteristics are considered. A model of a slope surface composed of n segments is constructed to realize the arbitrary generation of irregular geometric morphologies. Based on the upper bound limit analysis and the log-spiral failure mechanism, a formula for the factor of safety of slopes with irregular geometric morphology is obtained. Optimal stability analysis of convex, concave and convex-concave combination slopes with different characteristics is carried out. This paper mainly focuses on the effect of the location and extent of convex-concave sections on slope stability and sliding surfaces. In addition, a comparative analysis is carried out from both theoretical and numerical perspectives. The local stability of convex and convex-concave combination slopes is discussed. The results show that the effect of convex-concave characteristics on slope stability is related to the equivalent straight-slope angle. Moreover, some abnormal phenomena have been identified. For example, under certain conditions, the stability of a convex slope is better than that of a straight slope, and a concave morphology is not conducive to slope stability. In addition, when the equivalent straight-slope angle is small, convex-concave combinations can yield the worst or best slope stability. Therefore, the location and extent of convex-concave sections should be comprehensively considered to achieve an optimal design scheme in slope reinforcement design and construction. [ABSTRACT FROM AUTHOR]

This paper illustrates the scope and contribution that the discipline of geomorphology can offer in environmental litigation. The case in question was filed by two plaintiffs who contended that the construction of a storage facility on an adjacent property had caused significant disturbance of the topsoil, and that runoff from the impermeable surfaces (e.g., roofs, driveways) had exacerbated the problem by eroding and transporting soil and fill material from the facility directly into three ponds owned by them. They sued for $1.6 million to cover dredging, restoration of the ponds, and disposal of the sediment. Utilizing a range of geomorphological techniques, I was able to determine the most likely source area(s) of eroded sediment within the basin and quantify the extent to which the defendant's property contributed runoff and sediment to the ponds. The lawsuit was dismissed before ever going to trial. In the paper, I discuss the steps involved in the process of being an expert witness and also share some of the advice I have received from attorneys with whom I have worked. I emphasize the importance of setting any case study within a larger spatial context and encourage my fellow geomorphologists to become involved as experts in litigation because, in most instances, we can contribute to an appropriate outcome. [ABSTRACT FROM AUTHOR]

Drainage network systems are responsive elements to recent active tectonics from among all the topographic features. In geodynamically active areas, fluvial landscapes can record different processes through the formation and current presence of features related to spatial-temporal variation in base-level fall and vertical incision of stream channels. This study focuses on the tectonic evolution of the Alessandria Basin, a synorogenic tectonic basin located at the junction between the Alps and the Apennines, that experienced progressive subsidence during the overthrusting of the Monferrato Thrust Front (the westernmost outer arc of the Apennine belt) onto the Po Foreland Basin. Even though several studies have assessed the Neogene tectonic evolution at a regional scale, rates and timing of the Quaternary activity are still poorly understood in terms of both Alps/Apennines uplift and activity of the compressive front of the Monferrato Arc. In this paper, we applied the method of the river profile linear inversions to reconstruct the base-level fall history of 6 catchments that drain into the Alessandria Basin. We used nine 10Be-derived basin-average denudation rates to constrain the erodibility parameter needed to infer base-level fall rates from χ-transformed river profiles. The results describe the tectonic history of the area in the last ∼5 Ma, documenting increases in base-level fall rate with an initial peak between 3 and 2.5 Ma, and a second between 2 and 1.5 Ma. While the first peak is coeval with the uplift phase that involved most of the northern-central Apennine, the second one suggests an acceleration in subsidence of the Alessandria Basin concurrently with the uplift of the Monferrato Thrust Front. [ABSTRACT FROM AUTHOR]

Understanding and predicting dune erosion is crucial for coastal hazards mitigation, ecosystem preservation, as well as the protection of human settlements and infrastructure along sandy coastlines. However, our knowledge regarding the influence and potential importance of internal sand moisture content on wave-driven dune face erosion processes remains limited. This paper presents the findings from an extensive series of controlled wave flume experiments of eroding, unvegetated dunes, combining a range of wave conditions and water levels. A further variable that is studied directly for the first time is the internal moisture content of the dune. The initial moisture content and its evolving dynamics within the eroding dune face are quantified, revealing this to be a determining factor of the observed erosion rates, the final horizontal erosion distance, and the dune face failure type. Importantly, infiltration into the dune with each wave was not a driving mechanism of observed failures, but rather the rapid increase and then decrease of the phreatic surface within the dune, resulting in excess pore pressures and destabilization of the sediment matrix. Based on these observations two distinct mechanisms of shear failure and resulting dune face slumping are identified for unsaturated dunes corresponding to 'minimum' and 'field capacity' internal moisture content: Type 1 is associated with a circular failure surface in the absence of notching at the base of the dune, while for Type 2, notching is present and the failure surface is vertical. Under fully saturated conditions, the phreatic surface is observed to decouple from the wave runup, with excess water continuously exiting the dune face near the base. This results in rapid shear failure with no notching (Type 3). Significantly, dunes with saturated initial pore moisture content above the capillary fringe are observed to have up to 35 % greater erosion potential, consistently receding further landward than the two unsaturated counterparts as well as undergoing slumping in the absence of wave impact. A new conceptual framework is presented, comprising of a three-phase erosion sequence that directly links dune face failure mechanisms to wave runup and prevailing groundwater conditions. • A series of controlled wave flume experiments is conducted to examine dune erosion processes. • Internal dune moisture shown to affect the rate and magnitude of dune erosion • Internal dune moisture determines the failure mechanics of the dune face. • Saturated dunes observed to erode faster and to a further landward extent by 20–35 % • A conceptual framework incorporating hydrodynamic forcing and internal moisture dynamics is presented. [ABSTRACT FROM AUTHOR]

Long-term rates of escarpment retreat in sedimentary tablelands have been rarely determined and their possible variability in relation to major environmental changes has often been speculative, especially in older contributions. Moreover, rates reported so far were almost exclusively from arid regions. In this paper we present a dataset of 20 cosmogenic exposure ages, obtained for cliffs and boulders produced by rock-slope disintegration, left in front of a retreating 150-m-high escarpment of a sandstone mesa in SW Poland. The most distant boulders are >400 m away from the cliffs. Following previous research in the region, boulders are mainly products of in situ disintegration and hence, their present-day position on the slope approximates the past position of the cliffs, allowing for the calculations of cliff retreat. Exposure ages systematically increase with the distance from the present-day cliff line and cover the last 100 kyr, implying an average retreat rate of 4.18 mm/yr. However, the dataset splits into several sub-populations, each with its own trend, meaning that the rates of retreat varied with time. A maximum was reached during the Late Pleistocene and transition to the Holocene, when the rates exceeded 10 mm/yr and may have reached 100 mm/yr. The rates seemed distinctly lower between MIS5 and LGM and during the Holocene. We propose that the transition towards a warmer climate at the Pleistocene/Holocene boundary, with an increased frequency of freezing-thawing cycles, the degradation of permafrost and unblocking of groundwater drainage enhanced caprock disintegration and accelerated the break-off rates of caprock. During periods of most efficient cliff disintegration and boulder production the rates of escarpment retreat at the field site could have been two orders of magnitude higher than in the hyperarid areas. However, despite changing rates of retreat major processes involved in escarpment evolution seem to have remained the same. [ABSTRACT FROM AUTHOR]

Large wood (LW) and log jams have important implications for sediment dynamics within river systems. Although many case studies explore this topic, far fewer synthesize these results at the reach and basin scales. In this paper, we present a conceptual model that relates valley setting and landscape history of forested, mountain streams to spatiotemporal patterns of sediment storage and transport via the formation and decay processes of logjams. This conceptual model explores the function of logjams as sediment transport moderators, significantly influencing sediment retention, channel morphology, and lateral and longitudinal connectivity. Detailed wood inventories, channel topographic surveys, and channel morphology from four case studies are used to illustrate the range of channel responses to logjam formation, evolution, and decay in different valley contexts. Valley setting is shown to influence logjam formation and dynamics by determining the mechanisms and timing of sediment and wood recruitment. In steep and narrow (and thus coupled, confined) reaches, colluvial processes are the dominant mechanisms of wood and sediment delivery, and logjams grow vertically as sediment is stored in a wedge behind the jam (longitudinal disconnectivity). In contrast, in unconfined reaches (decoupled hillslopes), wood and sediment recruitment occurs primarily through fluvial processes, and logjams grow laterally as the channel shifts across the valley bottom. These logjams have long lifespans, often over a century, and gradually release sediment as the logjam decomposes. Sediment deposits stabilized by riparian vegetation behind these structures may persist long after logjam decay. This conceptual model is a testable framework and practical tool that offers insight into wood-sediment interaction mechanisms within steep, forested basins. [ABSTRACT FROM AUTHOR]

Stream bend geometry is linked to terrain features, hydrologic and ecologic conditions, and anthropogenic forces. Knowledge of the distributions of geometric properties of streams advances understanding of changing landscape conditions and associated processes that operate over a range of spatial scales. Statistical decomposition of sinuosity in natural linear features has proven a longstanding challenge and a particular impediment to automated analysis. This paper demonstrates that sinuosity can vary with the magnitude of units at which it is measured (measurement scales). The paper derives a scale-specific sinuosity (S3) metric intended to measure stream bend geometry across a range of measurement scales. The metric is warranted for analysis and modeling at measurement scales equal or similar to the spatial process and landscape conditions under investigation. Derived from the Richardson (1961) plot, the S3 metric quantifies a frequency signature of planform bend sizes spanning a range of measurement units, enabling visual and quantitative analysis of bend geometry in linear stream features. Derivation of the metric makes evident a systematic relationship between stream bend size, sinuosity, and measurement scale, formalizing a relationship between sinuosity and fractal dimension. The paper shows the utility of the S3 metric in examining bend patterns for synthetic and real-world linear stream data. • Scale-specific sinuosity (S3) summarizes bend sizes of linear features and associated contributions to sinuosity across a range of scales. • The S3 plot is analogous to a frequency histogram of bend sizes, like a fingerprint or a spectral signature. • The S3 is an easily computed metric to assess influential scales in bend patterns of linear stream features. • The paper formalizes a relation between sinuosity and fractal dimension. [ABSTRACT FROM AUTHOR]

River sediment budgets are prepared globally, under different conditions and requirements. This paper proposes a general methodology for sediment budgeting – the River Sediment Budget Approach (RSBA), to demonstrate the challenges and opportunities involved in establishing a sediment budget. The methodological approach focuses on the bedload, suspended sediment load as well as changes in the river bed and morphology. Four approaches are provided for sediment budgeting, which can be used individually or in combination and are selected based on the time scale and data availability. If measurement data is available or can still be undertaken, a (i) field-based approach is selected. Specifically, the morphological changes or data required for formulas can be gathered using a (ii) GIS-based approach. When calculations are carried out without measured data, a (iii) formula-based approach is pursued. Due to the numerous budgets already conducted and sediment data already measured, an approach dependent on (iv) literature data and estimations can also be considered. Due to the complexity of sediment dynamics in rivers, strict rules are not beneficial in sediment budgeting and, to avoid misinterpretation, it is essential to validate the results. • A budget approach (RSBA) with a hierarchical decision matrix. • Sediment budgets as a methodology to budget suspended sediment and bedload at different temporal and spatial scales. • Opportunities for sediment budgeting with weak datasets. [ABSTRACT FROM AUTHOR]

The morphodynamics of inlets and ebb-tidal deltas often exhibit cyclic behaviour, controlled by wave-tide interactions and the influence of these on sediment-bypassing processes. Variation in the form and timing of inlet dynamics can occur in response to changes in the key sediment transport processes and sediment supply, and particularly the relative dominance of differential wave direction driving alongshore sediment transport. This paper investigates the morphodynamics of the Deben ebb-tidal delta through multivariate analysis of multi-annual bathymetry and metocean parameters covering the period 1991 to 2023. Results show that sediment bypassing and associated morphological change in this ebb-tidal delta follows variable behaviour mid-cycle, leading to change in the morphology and configuration of the ebb-delta from cycle to cycle. In the most recent cycle (since 2003), delta volume followed a stepwise growth driven by sediment influx periods, evident primarily in the updrift shoal, followed by cross-shore redistribution. Interannual variability in wave climate was clustered into four groups that capture the relative balance between the dominant NE and SW forcing. Sediment influx periods are mostly associated with subdued SW and increased NE forcing, but the summer and winter NE wave climate play different roles on the up- and downdrift, and upper and lower components of the ebb-delta system. Tide level has increased in the last 33 years, which is strongly correlated with ebb-delta volume increase. Wave and tide conditions have discrete and independent effects on the ebb-tidal delta, whereas wave-tide interactions do not significantly change these underlying influences. • Differential within-cycle behaviour was found in multidecadal bypassing cycles. • Ebb-tidal delta volume has increased via a stepwise growth. • Sediment influx is related to reduced SW and increased NE wave forcing. • Wave and tide conditions have independent effects on the ebb-tidal delta. [ABSTRACT FROM AUTHOR]

Mixed sediment beaches are globally commonplace, yet little is understood of the extent and behaviour of their nearshore zones, potentially underestimating total cross-shore change. This paper is the first study to investigate the lateral and vertical extent of the active zone of the gravel-rich mixed beach in Pevensey Bay, a study site on the South East UK coastline. Morphodynamic change in the nearshore zone was studied at a range of timescales (days, months, years) suggesting that the width of the active nearshore zone correlated with the magnitude of the peak morphological change, whilst the depth of closure was influenced by bed slope, grain size and local variation in wave conditions. A conceptual model detailing the physical parameters responsible for local variations in the depth of closure was used to help understand differences between the observed and predicted depths of closure. Finally, ongoing chronic loss of sediment from below Mean Sea Level (MSL) was examined, which was shown to be independent of the depth of closure, but closely linked to the wider geomorphic setting of the bay. • Comparison of observational and predicted depth of closure for a mixed sediment beach • Local variations in the observed depth of closure examined using a conceptual model • Magnitude of subtidal bed elevation change may be controlled by sediment availability. • Loss of nearshore sediments over time reflects the trend in upper beach steepening. [ABSTRACT FROM AUTHOR]

With the rapid escalation of human activities and the exacerbation of global warming, the safety assessment of landslide dams has become increasingly crucial. Quickly and accurately evaluating their safety presents a significant challenge. This paper conducts a comparative analysis of six AI classifier models designed for assessing landslide dam stability, employing both the random forest method and the XGBClassifier method. These models are developed based on seven inputs: dam height, dam length, dam width, dam volume, dammed lake volume, catchment area, and dam material, with one output representing stability. In addition, these innovative models handle landslide dam data with missing values using zero filling or NaN (Not a Number) filling, with and without log-transformation. The stability performance of these six AI models is evaluated using metrics such as accuracy, precision, recall, and F1-score. Furthermore, data from 16 on-site landslide dams are collected and then utilized as case studies for the evaluation. Results reveal that the XGBClassifier model, integrating NaN values and coupled with log-transformation, achieves the highest classification accuracy rate at approximately 75.33 % among the six models. Additionally, it demonstrates the highest F1-score of 0.82 in predicting actually unstable dams. In the context of case studies, this model also attains an accuracy of around 68.75 %, signifying a notable improvement over traditional methods such as Blockage Index (BI), which achieves an accuracy of 31.25 %, and Dimensionless Blockage Index (DBI), which achieves an accuracy of 37.50 %. Thus, AI models exhibit significant potential for markedly enhancing the rapid prediction of landslide dam stability when compared to traditional approaches. [ABSTRACT FROM AUTHOR]

Land-surface quantitative analysis based on digital elevation model (DEM) has been applied for improving the geomorphological mapping of piedmont alluvial fans. Indeed, these fans are frequently along a mountain front, where a series of coalescing fans may eventually occur. The margins of adjacent fans are rather difficult to map, thus preventing accurate and meaningful quantification of fan morphometric properties such as fan area, length, and slope. These morphometric properties are essential for informing on the influence of climatic conditions and tectonic factors on the fan-building processes. Therefore, in this paper, we propose a quantitative digital mapping approach along a stretch of about 50 km in the southern front of the Anti-Lebanon Mountains. Here, the Geomorphological Map of Syria at 1:1,000,000 scale (1963) reported at least nine piedmont alluvial fans, but these were poorly characterized in terms of geomorphometric characteristics and construction processes. Adopting the 1-arcsec SRTMv3 DEM, we propose a four-step workflow to analyse the feeding catchments morphology and fan morphometry. In this manner, the identification and geomorphological mapping of coalescent piedmont fans as well as the recognition of the main construction process have been improved. The proposed approach can support geomorphological investigations of wide and inaccessible areas—especially where arid and semi-arid climate conditions prevail—as well as where socio-political issues may prevent effective field work. • Land-surface quantitative analysis is suitable for geomorphological mapping and characterization of piedmont alluvial fans. • Recognition of the construction processes of the alluvial fan is challenging for a remotely-desk study. • Fluvial fans (FFs) are wider, with longer axis, gentle slope, and extended feeding catchment. • Alluvial fans (AFs) are smaller, with shorter axis, steeper slope, and small feeding catchment. [ABSTRACT FROM AUTHOR]

Large-scale landforms originated from jökulhlaups or glacial lake-outburst floods (GLOFs), and their small-scale components help in recognising the sedimentary environment of the flood. The GLOF fans that developed along the Pleistocene ice-sheet margin have not been investigated in detail, and north-eastern Poland, with its Megaflood Landform System and Bachanowo and Szeszupka fans, seems ideal for landform and sedimentary studies. This paper provides (1) an important opportunity to recognise the origins of glacier lake-outburst flood outlets and their evolution during two GLOFs and (2) a model of the origin of ice-marginal fans considering changes in sedimentary environment reflecting flood stages. During the first GLOF (GLOF1), the rising stage of meltwater burst triggered the formation of a supraglacial outlet and the development of the Szeszupka outburst fan. During the pulsed peak discharge, subglacial multi-channelised meltwater outburst caused the formation of the Bachanowo Gate, which was finally transformed at the flood waning stage. Such processes were associated with the widening of the floodwater subglacial routeway, when floodwater outlets rapidly spread across the glacier snout. In contrast, GLOF2 was responsible only for the Szeszupka fan erosion and development of outburst terraces. The small-scale bedforms continuum, recognised on the outburst fan surface, is associated with the development of streamlined erosional residuals, scours and their trains during the rising stage and peak discharge, while the waning stage and very end of flood conditions were favourable to the formation of pendant bars, distributive channels with erosional bars and chute bars, regardless of the feeding systems of the outburst fans. The fan deposits were OSL-dated and revealed either, likely, overly old ages or an age of 13.2 ± 0.9 ka. The latter age would imply the 'normal' meltwater outflow having a correlation with the events in the region. Nevertheless, this age might be considered a minimum age of the flood. • Supraglacial outlet developed first due to hydrofracturing during the rising GLOF stage. • The second outlet started to form at the peak discharge due to subglacial multi-channelized drainage. • The dominant processes in outburst fan formation are riverbed scouring and subsequent sediment deposition. • The small-scale bedform continuum evolved on outburst fan surface in relation to GLOF stages. • Outburst fan deposits were OSL-dated and revealed too old ages or an age of 13.2 ± 0.9 ka. [ABSTRACT FROM AUTHOR]

Ongoing climate change has increased the impact of landslides and related slope disasters on infrastructure and human lives. Microwave satellite remote sensing, particularly interferometric analysis of synthetic aperture radar (InSAR) data, is a powerful tool for routine monitoring of the displacement of slopes on small wavelength scales, independently from solar illumination and cloud coverage. Although various sophisticated techniques for time-series InSAR have been developed, practical application in conjunction with geological analysis to reveal intrinsic and triggering factors of slope displacement is still limited. In this paper, we describe a practical case of time-series InSAR analysis with a special focus on its geological implications in northwestern Kyushu, a high-risk area for slope-related disasters in Japan. The extracted susceptible polygons from the InSAR results show accuracy comparable with that of other recent research on landslide mapping. Intrinsic factor analysis based on a geographic information system reveals that the displacement occurs on relatively gentle slopes instead of steep areas, corresponding to the transient zone of Paleogene-Neogene sedimentary rocks and basalt. Triggering factor analysis based on correlation coefficients reveals a significant link between some displacement areas with mean and/or maximum precipitation for each observation duration. Those findings confirm the importance of carefully accounting for the geological background for landslide susceptibility assessment and policy making, apart from topographic and meteorological conditions. [ABSTRACT FROM AUTHOR]

The deformation and displacement of landslides has always been the priority of landslide monitoring and early warning. With the development of image processing technology in recent years, the analysis of landslide surface deformation through image data has become a popular method and different methods of image analysis are rapidly increasing. However, the current method of analyzing landslide deformation and displacement using a single image processing method tends to analyze the displacement of the local deformation area of the landslide, which lacks overall monitoring of the slope and is difficult to use for pre-disaster monitoring of landslide hazards, easily leading to missed detection of landslide potential hazard points. Therefore, this paper combines image recognition technology and computer vision (IR-CV) to propose a method for monitoring and identifying the deformation displacement of landslide surfaces, which has been validated by indoor landslide model tests and unmanned aerial vehicle field simulation displacement recognition tests. In the model tests, the IR-CV method successfully identified the displacements generated during the deformation and damage of the landslide model while using the model deformation time series image data recorded by the camera to analyze the overall deformation of the surface of the landslide model. Further, in this paper, a field simulation displacement identification test was conducted using an unmanned aerial vehicle (UAV), and the orthophoto data obtained by the UAV verified that the IR-CV method can be used for overall deformation displacement identification of landslides in the field. The results of indoor model tests and field UAV simulation tests show that the monitoring method of IR-CV can effectively identify the deformation and displacement of landslide surfaces, which has good application prospects in pre-disaster monitoring and displacement identification of landslides, thus providing a cost-effective and feasible solution for monitoring the deformation and displacement of landslide surfaces. [ABSTRACT FROM AUTHOR]

This paper describes the in-situ implementation of a recently developed bedload transport estimation method, called Acoustic Mapping Velocimetry (AMV). The method combines components and processing protocols from acoustic and image-based methods to provide velocity maps of bedforms migrating in the riverbed. The AMV implementation is illustrated with repeated Multibeam Echo Sounder (MBES) mappings that are acquired along longitudinal swaths over the entire transect of the study river sections. The paper exemplifies AMV implementation case studies leading to the estimation of bedload transport rates in two large sand-bed rivers: the Ohio and Mississippi rivers, in the USA. The analysis associated with these case studies emphasizes the importance of linking the characteristics of the bedform dynamics with the selection of the spatio-temporal parameters used during data acquisition for AMV processing (e.g., required length of the measurement section, and the effect of the time lag between the repeated surveys) for accurate quantification of bedform dynamics. The role of superimposed secondary small bedforms migrating over the large primary ones, in terms of their contribution to the sediment transport, is also discussed. The paper demonstrates the applicability of this novel technique, as a complement or stand-alone method for quantifying bedload transport in large sand-bed rivers, an area where the implementation of conventional methods is difficult and inadequate while the emerging measurement alternatives are not widely recognized yet. [Display omitted] • AMV combines high resolution riverbed scannings with image velocimetry techniques to estimate bedload transport in rivers • AMV provides 2D velocity maps of bedform migration enabling more accurate bedload estimation than 1D approaches • AMV is a robust and automatable indirect technique that can substitute direct sampling methods in large sand-bed rivers [ABSTRACT FROM AUTHOR]

This paper investigates, from a geomorphological and hydrogeological point of view, the development of piping-sinkhole phenomena at a retreating fluvial-terrace scarp along the lower Ticino River, near Casottole, northern Italy. Piping forms and features are well documented in the literature as complex soil erosion phenomena, usually associated with clayey or carbonate substrata, or to specific fluvial deposits. Such phenomena appear to have never been mapped in the lower Ticino area, and up to now, no evidence of piping-sinkhole occurrence in terraced alluvial plains strictly associated with terrace scarp erosion processes have been observed and reported in the literature. The geomorphological peculiarities of the area were assessed through field surveys, photographic and drone imaging, photointerpretation, and GIS analysis. Moreover, the riverbed morphological evolution was evaluated since the 1950s, and the hydrogeological conditions were analysed. Finally, a large piping-sinkhole database composed by 35 landforms was assembled in a WebGIS system. The piping-sinkhole phenomena were associated with the presence of perched water tables with flows towards the Ticino River, whose origin can be associated with site conditions, the large up dip network of surface water, and local irrigation practices. The research presented here provides a new contribution to the understanding of sinkhole occurrence and formation in previously unstudied terrace-scarp settings, and new insights for fluvial-terrace scarp modelling. Furthermore, it represents an important knowledge base to inform sustainable and effective measures for environmental management and hydrogeomorphic risk mitigation with reference to terrace scarp erosion and sinkholes. • First description of piping-sinkholes forms and features in the lower Ticino River • Large (up to 50 m) scarp piping-sinkholes straddle the retreating terrace scarp edge. • Decades of observations show direct relationship with river meander migration. • Piping-sinkholes can form suddenly causing important disruption. • The forms are still evolving due to a combination of natural and anthropic factors. [ABSTRACT FROM AUTHOR]

This study presents the characterization and chronology of the Quaternary terrace sequence developed in the confluence zone of the Júcar and Cabriel river valleys. The study area covers a radius of 10 km from the confluence of the two valleys near the locality of Cofrentes (Valencia). It is located in the northern zone of the Ayora-Cofrentes Graben in the northeastern sector of the External Prebetic Zone adjacent to southern Iberian Chain. This N-S graben is an inherited tectonic feature with an axial salt wall subject to different periods of fluvial dissection and refilling since at least the end of the Messinian Salinity Crisis (MSC). Regional isostatic uplift and local uplift and subsidence processes related to salt flow and dissolution during the Quaternary period, favored by fluvial entrenchment and terrace development. The terrace system and the previous pre-incision erosional and depositional surfaces are analyzed from a geomorphological point of view. The terrace system only develops within the soft Mio-Pliocene sedimentary fill of the graben, whilst upstream and downstream this zone the studied valleys develop important gorges (canyons) carved in the Cretaceous tablelands (Caroch Massif) and Mio-Pliocene deposits (Llanura Manchega). The geochronological control is established from 20 numerical ages obtained by different dating methods, such us Electron Spin Resonance (ESR), Optically Stimulated Luminescence (OSL) in detrital sequences and Th/U series in calcareous tufa deposits. Additionally, four K/Ar dates available for volcanic materials disrupting the upper and oldest terrace have been considered. A total of 14 terrace levels were identified between +130–135 m (T1) and +3–4 m (T14) of relative height above the river thalwegs. The T1 has an approximate age of c. 1.6–2.0 M.a. as indicate the age of the volcanic materials from the Agras Volcano intruded in the terrace, marking the onset of Quaternary fluvial dissection in the zone. The obtained geochronological data indicate that the Lower-Middle Pleistocene boundary is slightly above T6 (+60–65 m), which has an ESR age of 577 ± 43 ka. This terrace also documents the onset of the most important period of rise of the salt within the graben interfering drainage development. The geochronological data indicate the occurrence of a second eruptive event during the second half of the Middle Pleistocene related to the terraces T7 (+50 m) and T8 (+35–40 m), updating the volcanic activity in the zone. The beginning of the Upper Pleistocene is recorded by the top sequences of the T9 terrace (+25–30 m) where numerous OSL and Th/U data have been obtained with ages between ca. 105 and 81 ka (MIS 5). However, these young terraces (T8 to T13) are thickened (8–10 m) recording Middle Pleistocene sediments in their basal sequences with ages between ca. 193 and 137 ka (MIS 6). The study provides important data on valley evolution under the interference of volcanic activity, salt –related deformation (diapirism, solution subsidence) and fluvial incision fostered by the rise of the axial diapir (salt wall) protruding the graben since at least the Brunhes-Matuyama boundary. The analyzed fluvial evolution documents interesting cases of river capture, drainage antecedence and tectonic adaptation of the drainage throughout the Quaternary Period. The paper also poses interesting geochronological data on the long-term Quaternary evolution of Mediterranean valleys in the Iberian Peninsula, poorly explored to the date. [Display omitted] • The evolution of the Júcar Fluvial system (Spain) is addressed for first time supported. • The catchment contains a complex sequence of 14 terrace levels up to +135 m • Terrace sequence is dated within the last 2.0 Ma using K/Ar, Th/U, OSL and ESR data. • Phreatomagmatic activity disrupts valley evolution during the Lower-Middle Pleistocene • Cases of river capture, drainage antecedence and tectonic superposition are documented [ABSTRACT FROM AUTHOR]

This paper discusses a model of coastal barrier progradation where the development of a prograded plain was a product of the successive formation of foredune ridges followed by their burial by transgressive sand sheets and dunefields. The results are based on direct lithological data from drill holes and geomorphological analyses, indirect geophysical data (GPR), and 14C and OSL dating. Barrier progradation started at 6.69 ka (OSL) or 7.2 ka (14C), under sea-level rise. At around 5.0 ka (OSL), or thereabouts, a forced regression condition started to operate, when sea-level started to fall after it reached a maximum of 2.34 ± 0.8 m. During barrier progradation sets of foredunes were formed, and at least some of them were buried by sands of transgressive dunefields (TDF), which later evolved to transgressive sand sheets (TSS). A total of 11+ phases of TSS and a modern phase of TDF were formed in a time span of 6.69 ka (OSL) or 7.2 ka (14C), corresponding to one phase formed at each 560 or 600 yrs. Two models of possible development of the surface of Curumim barrier are proposed. • Arare record of aforedune plain buried by transgressive sandsheets formation. • The cyclic formation of transgressive dunefieldsand transgressive sand sheets. • The foredune/beach contact as a proxy of sea-level position. • Distinct contributions of normal and forced regressionon barrier progradation. • Possibletransformation of a transgressive dunefield in a transgressive sand sheet. [ABSTRACT FROM AUTHOR]

This paper presents new sedimentological, geomorphological, and optically stimulated luminescence (OSL) geochronological evidence for fluvial evolution of the mid- to lower River Tyne through the Lateglacial to late Holocene. These data reveal a series of fluvial terraces produced by cycles of aggradation and incision, conditioned by glacial inheritance and driven by changing sediment availability and hydrological regime. The distribution and stratigraphy (where available) of nine river terrace and their associated sediments have been recorded. At two key sites the sediments have been dated using OSL measurements to constrain the fluvial geomorphology. Significant entrenchment of the fluvial system, followed by aggradation formed the earliest fluvial terrace (T1), which encompasses environments spanning the transition from deglaciation into Greenland Interstadial 1 (GI-1). Incision below T1 began towards the end of GI-1, with three terraces (T2 – T4) between the abandonment of T1 and the early Holocene (15.0–9.2 ka). Climatic shifts, limited vegetation cover/soil development, and peri −/paraglacial landscape instability conditioned the development of the early postglacial fluvial landsystem. Three further terraces (T5 – T7) developed during the mid- to Late Holocene (6.6–3.1 ka), and comprise most of the valley floor. Climatic instability, glacial inheritance, and widespread anthropogenic disturbances are reflected in greater hillslope-channel coupling during this period. The extent of later Holocene terraces (T8 – T9) is limited as the river became isolated from flanking hillslopes entrenched between existing river terraces. Fluvial landscape evolution in formerly glaciated catchments is strongly conditioned by the cold stage legacy that introduced excess sediment and landscape instability into the catchment. Subsequent catchment-wide responses are variable and non-linear, with valley floors operating in a series of reach-wide responses. There is a need for greater chronological control to constrain the Lateglacial and Holocene evolution in the Tyne catchment, but also to further our understanding of region-wide responses to external drivers and local dynamics. • Lateglacial to late Holocene fluvial response recorded from river terrace sequence. • Fluvial landscape strongly conditioned by glacial legacy. • Catchment-wide responses are non-linear and valley floors operated as reach-wide responses. • River responded to climate and/or landscape perturbations at ∼16, 11.9, 8.7, 4 ka. [ABSTRACT FROM AUTHOR]

During major floods, rivers erode their banks and thus recruit large wood pieces from the riparian zones. There is still a lack of knowledge about the transport of large wood, the volumes involved and the flux distribution, i.e. the large wood connectivity at catchment scale. During storm Alex (October 2020), the French Roya catchment (394 km2) experienced a paroxysmal morphogenic flood involving massive bank erosion. The riparian vegetation was largely recruited, with large wood contributing to logjams and bridge destruction. This paper presents a methodology for volumetric assessment of the large wood fluxes involved. Simple approaches are used to (i) quantify the inputs from stand density data from the national forest inventory and from source areas based on diachronic analysis of active channels highlighting the erosion of 87 ha of wooded areas; and (ii) quantify the volumes deposited via an exhaustive manual digitisation of 16,846 pieces of large wood deposited on 59 km of channels on the Roya and its tributaries. This catchment-scale, large wood connectivity analysis shows that the flood recruited and transported downstream a volume of around 14,000 m3 of large wood (uncertainty range: 7000–29,500 m3). Drone observations of the Roya River mouth in Italy and satellite images showing a raft of driftwood, several km long, drifting off the Roya River mouth in the aftermath of the flood corroborate our findings. • Storm Alex (Oct. 2020) triggered dramatic geomorphic changes in the Roya River (FR). • We quantified the volume of large wood (LW) eroded, conveyed and deposited. • Large wood production is deduced from eroded forest maps and forest stand density. • Large wood deposition is estimated by digitizing logs on aerial pictures. • Circa 14,000 m3 of LW were recruited, 900 m3 deposited, the rest went to the sea. [ABSTRACT FROM AUTHOR]

Yibin area is located in the southwestern margin of Sichuan Basin of upper Yangtze River basin, close to the southeastern boundary of the Qinghai-Tibetan Plateau. The paleoclimatic characteristics recorded by Quaternary river sediments in this area can display the impact of uplift of the Qinghai-Tibetan Plateau on paleoclimate change of Sichuan Basin. In this paper, the macro-characteristics, clay minerals and the diagnosis geochemical elements characteristics of the sediments of terraces and floodplain were used as climatic proxies to explore the evolutionary process of the Quaternary paleoclimatic change in the study area. Key findings can be shown as follows: 1) warm and humid paleoclimate occurred during the Middle Pleistocene and the early Late Pleistocene (730–90 ka), shown by the high values of Al 2 O 3 , Fe 2 O 3 , Rb/Sr, chemical index of alteration (CIA, 82–97), illite chemical index (ICI, >0.5), kaolinite and the low values of Na 2 O, K 2 O, MgO, K 2 O/Al 2 O 3 , (CaO + Na 2 O)/Al 2 O 3 , illite, smectite, chlorite from the brown or brownish-red sediments of the terraces T5 to T3. 2) The reversal values of these geochemical and clay mineral proxies (e.g., values of CIA between 50 and 64) derived from grey and greyish-yellow sediments in terrace T2 and floodplain denote the dry and cold paleoclimate, emerging in the middle-late Late Pleistocene (50 ka), corresponding to the Baiyu glacial period of the Qinghai-Tibetan Plateau. Comparing the paleoclimatic evolutionary characteristics in Yibin area with those of the Three Gorges area of northeastern margin of Sichuan Basin from previous researches, this paper considers that during the Gonghe tectonic movement (0.15 Ma), the uplift of the Qinghai-Tibetan Plateau and its southeastern boundary intensified the Plateau winter monsoon and caused the southwesterly withdrawal of the Indian monsoon from Sichuan Basin. Consequently, the warm and humid paleoclimate at the northeastern and southwestern margins of the Basin had successively become dry and cold in the early and middle-late periods of the Late Pleistocene. • Paleoclimate information can be well preserved in terrace sediments in Yibin area. • The paleoclimate in Yibin area had changed from warm and wet to cold and dry since 50 ka. • Quaternary paleoclimate changed to dry and cold from northeast to southwest in the Sichuan Basin. • Tibetan Plateau's Gonghe tectonic movement enhanced the Plateau monsoon and blocked the Indian summer monsoon. • Influence of Indian summer monsoon weakened in the Sichuan Basin along the SW direction after 110 ka. [ABSTRACT FROM AUTHOR]

With the availability of improved digital elevation models (DEMs) of global coverage, the morphological analysis of large populations of glacial cirques is possible, and can be used to derive important palaeoclimate and environmental information related to the distribution and history of former glaciers. In 2017, an ArcGIS toolbox, ACME (Automated Cirque Metrics Extraction), was developed to derive 16 cirque metrics based on input cirque outlines, threshold midpoints and DEMs. ACME has been widely used in cirque morphological analysis and regional comparisons. This paper presents a revised and extended toolbox, ACME2. This extended toolbox includes new functions to automatically derive cirque threshold midpoints (cirque foci) and 49 morphometric and locational variables, with attributes related to cirque location, size, shape, altitude, slope, and aspect, including variables related to the median axis, as well as 3 input metadata attributes. ACME2 also improves the methods for calculation of the hypsometric maximum and integral, and implements a new method for plan closure to be more consistent with the original definition. All ACME2 tools are coded in Python and can be imported into ArcGIS with user-friendly interfaces. Comparisons for 155 cirques in the English Lake District and 51 in the Shulaps Range, British Columbia, indicate consistency between the ACME2-derived and manually derived metrics, with most correlations r > 0.90: none <0.70. ACME2 provides more cirque metrics and automates the whole calculation sequence with cirque outlines and DEMs. Its comprehensive approach facilitates understanding of cirque form and development in all its variety. • We present an extended toolbox for automated cirque metrics extraction, ACME2. • ACME2 includes new functions to automatically derive cirque foci and 49 metrics. • A method for plan closure is developed to be consistent with earlier literature. • ACME2-derived and manually derived metrics are highly correlated in two test areas. • Tools and metrics can be used for the morphological study of other landforms. [ABSTRACT FROM AUTHOR]

Large wood (LW) can have significant effects on channel hydraulics by creating hydraulic resistance that decreases reach-average flow velocity and transport capacity, further influencing water and sediment connectivity. Although some case studies have already explicitly dealt with LW considering its effects on connectivity, a conceptualization as well as standardized methods or protocols to assess their effects on water and sediment connectivity in river systems are still missing. The relationship between in-stream LW depositions and their hydraulic function and the related potential effects on water and sediment connectivity can be quantified through drag force. However, such drag analyses are very data-demanding, time consuming and therefore often not practicable. Especially in river management, often simple and fast screening approaches are needed to get a system-wide overview on location, type and the potential effects of LW depositions. In this paper, we introduce a simple LW in-stream dis-connectivity index as well as a LW sediment retention potential index for streams narrower than log length calculated based on visually estimated field-derived parameters. Both indices have been applied in two mixed-load streams in an Austrian national park. The newly developed indices have shown to provide a simple means to quantify and compare the effects of LW on water and sediment connectivity and sediment retention potential between different river systems. Moreover, it has been demonstrated that information derived from the indices as well as on type and location is valuable for place-based river management, e.g. related to river sediment, habitat and flood control. Although we were able to show a clear relationship between the conceptual considerations of the proposed indices and the data derived from field surveys, the presented approach further needs to be tested and evaluated by interested scientists and practitioners in different environmental settings supported and corroborated by more quantitative data. • The developed indices provide a simple means to quantify the effects of in-stream LW on water and sediment connectivity. • The proposed approach can be useful in different river management contexts such as sediment and flood water retention. • In-stream LW disconnectivity and sediment retention potential depends on LW deposition type and the degree of blockage. [ABSTRACT FROM AUTHOR]

This paper investigates the relationships between hillslope stability and fabric anisotropy of brittle rock materials and the implications for landscape shaping. We use discrete element models to study the stability and failure modes of slopes made of transverse isotropic rock materials, focusing more particularly on the influence of the material orientation relative to the topographic slope. After validating the numerical approach with a limit equilibrium analytical solution in the case of an isotropic material, we modify our numerical slope models to simulate the rheological features of anisotropic gneissic rocks. Systematic exploration of the transverse isotropy plane's orientation in two dimensions (dip angle) reveals that slope collapse requires strength values that are highly dependent on the orientation of the material relative to the slope. For a 1000 m high escarpment, the stability of a slope with a fixed gradient requires strength that is one order of magnitude greater in a configuration where the isotropy plane is slightly less inclined than the topographic slope (i.e., cataclinal overdip configuration) than in a configuration where the isotropy plane is perpendicular to the slope (i.e., anaclinal configuration). Mirroring this highly variable stability according to the relative orientation of the material, four modes of deformation or gravitational instability are observed: in order of appearance, when the transverse isotropy plane orientation goes from 0 to 180° with respect to the horizontal (going from cataclinal to anaclinal configurations), the slope collapses respectively by sliding, buckling, toppling and crumbling. The crumbling mode corresponds to a very stable configuration for which the preferred ground movements will be rock falls from the cliff compared to the structurally controlled, deep-seated deformation modes leading to sliding and toppling. Despite the simplifications inherent to the numerical approach, our study highlights the essential characteristics of landslides occurring along slopes cut in transverse isotropic materials and reproduces the various instability modes observed in natural slopes. It also enables assessing their respective kinetics as well as the volumes of material they mobilize. Finally, by comparing our findings on the azimuthal variations in hillslope gradients observed along the central Himalaya (Nepal), in an area characterized by the relatively uniform orientation of the anisotropy in gneissic and mica-schist formations, we show that, even though multiple environmental factors come into play, landscape shaping is indeed strongly controlled by material anisotropy. • Anisotropic rock strength affects slope stability by foliation dip angle. • Stability and failure modes are investigated by means of discrete element models. • Sliding and buckling failures occur in cataclinal slopes. • Toppling and crumbling failures occur in anaclinal slopes. • Himalayan slopes confirm how anisotropy controls landscape evolution. [ABSTRACT FROM AUTHOR]

Shore platforms are generally supply-limited environments and few studies have attempted to measure sediment transport within this rock coast setting. This paper summarises a field-based pilot study that successfully collected fine-grain sediment moving across a sub-horizontal platform at Mudstone Bay, Kaikōura, New Zealand. Two large-aperture and two small-aperture Time-Integrated Mass-sediment Samplers (TIMS) were deployed for 9-days, encompassing 2 days of storm conditions (offshore significant wave heights between 2.0 and 3.6 m, with sediment trapped in both landward and seaward facing directions. The net flux of sediment captured in large aperture samplers was greatest in a seaward-direction (15.2 g), whereas the narrow-mouth samplers, that principally collected suspended sediment had a net onshore flux (5.4 g). The sediment traps yielded sufficient sample to undertake geochemical and textural analysis. Interpretation of these data suggests that the origin of transported material was autochthonous to the platform, being >80 % silt-sized and compositionally consistent with material derived from the shore platform and/or cliff colluvium. This pilot experiment demonstrates that mass-sediment samplers can be used in supply-limited intertidal shore platform settings. Further research involving greater sampling frequency and duration and concomitant detailed hydrodynamic measurements are likely to reveal important insights into the erosion environment. • TIMS can be used on an intertidal shore platform to collect saltating and suspended sediment in bi-directional flow. • Sediment caught in sufficient amounts to conduct provenance and geochemical analysis • Storm conditions were most favourable to collect both saltating and suspended sediment at Kaikōura. [ABSTRACT FROM AUTHOR]

The Bohai Sea is a semi-enclosed shallow shelf sea that has undergone a unique sediment source-to-sink process in the past. Despite this, our knowledge about the sediment budget, existence of depocenters and the factors controlling depocenter formation during the Holocene remains limited. This paper aims to address these gaps by estimating the Holocene marine deposit thickness and sediment budget in the Bohai Sea using high-resolution subbottom profiles. The results reveal that the mean thickness of Holocene marine deposits is approximately 7.8 m and a maximum thickness of 28 m was found in Jinzhou Bay. The Highstand System Tracts (HST) have a mean thickness of approximately 5.4 m and a maximum thickness of 25 m observed in the Jinzhou Bay. On the other hand, the Transgressive System Tracts (TST) have a mean thickness of approximately 2.5 m and a maximum thickness of 7 m in the north of the Laizhou Bay. The total accumulation in the Bohai Sea is estimated to be ∼713.97 × 109 tons, consisting of 489.28 × 109 tons from the HST and 224.69 × 109 tons from the TST. Three deposit centers were identified and estimated to be approximately 299 × 109 tons, accounting for approximately 42 % of the total Bohai Sea sediments. The development of Holocene marine deposit centers was mainly influenced by the Tanlu Fault zone and water circulations. Based on preliminary estimates, it is suggested that roughly half of the sediments dispersed from the estuaries are preserved on the Bohai Sea shelf since the maximum flooding (∼7000 cal yr BP). This research provides valuable insights for the post-glacial sedimentary and geomorphic evolution of the Bohai Sea. • Holocene marine accumulation in the Bohai Sea is estimated to be ∼713.97 × 109 tons. • Accumulation in HST is of ∼489.28 × 109 tons and that in TST is of ∼224.69 × 109 tons. • Three depocenters were identified and account for ∼42 % of the total accumulation. • Roughly half of the sediments were preserved on the shelf over the past 7000 years. [ABSTRACT FROM AUTHOR]

This paper aims to methodically examine the incipient characteristics of natural marine fine sediment with particle size less than 0.012 mm for a variety range of bulk densities. Theoretical derivation and experimental data analysis are appropriately combined to explore the effect of bulk density on the inter-particle cohesive force and to deduce the incipient shear stress (ISS) of fine sediment. Under the same particle size condition, the achieved results indicate that the ISS of sediment intensifies with the growth of the bulk density. In addition, the larger the bulk density, the faster the increase rate, revealing a power exponential growth trend. The ISS of sediment also magnifies with the reduction of the particle size under the same bulk density condition; however, as the particle size decreases to 0.007 mm, the ISS of sediment would no longer vary. The influential factors on the cohesive force, including intermolecular gravitational force, film water pressure, and bulk density, are thoroughly analyzed, and a rational expression for the cohesive force is also proposed. The modified shields parameter represents the ratio between the sediment driving force and the stabilization force (e.g., gravitational and cohesive forces) and is still a function of the sediment Reynolds number. The modified shields curve still follows the shape of the original shields curve and satisfies both cohesive and non-cohesive sediment conditions but with differences in the form of shields parameter. • Focus on sediment incipience with particle size less than 0.012 mm for various bulk densities • Collect 77 sets of Chinese offshore fine sediment initiation flume experiment data • Propose an inter-particle cohesive force expression by considering the role of bulk density • Derive a modified shields curve suitable to both cohesive and non-cohesive sediment [ABSTRACT FROM AUTHOR]

The overall purpose of this paper is to integrate the geomorphic evolution of Glen Canyon and Upper Colorado River Corridor with that of Grand Canyon in order to address two key enigmas: why did the Colorado River not arrive at the mouth of Grand Canyon until 5.5 Ma, and how did the Colorado River cross the Kaibab arch high? This evolution was approached from three different perspectives: (1) by reviewing geologic investigations in the Glen Canyon area from the late 1800s to the present; (2) by explaining how a paleo-Colorado River constrained within a lake or a chain of lakes on the Colorado Plateau is necessary for the Colorado River to have arrived at the mouth of Grand Canyon ca. 5.5 Ma; and (3) by proposing how the incision rates in Marble Canyon, Glen Canyon, and central Colorado Plateau may be related to a prolonged base-level fall at the Confluence of the Colorado-Little Colorado rivers starting at ~5.5 Ma, to a karst-connection model of a Colorado River crossing under the Kaibab arch, or to a lake-overflow model. An attempt was made to find field and analytic evidence for a pre-5.5 Ma Miocene lake along the north to west sides of Navajo Mountain, Utah, where high pediment surfaces still remain along the Colorado River, but from field investigations, 26Al 10Be cosmogenic dating, and SEM analysis, no direct evidence for a past lake was substantiated. However, a number of lines of indirect evidence are discussed supporting the possible existence of a Miocene lake or chain of lakes along Glen Canyon and Upper Colorado River Corridor. A lake-overflow model is compared with a karst-connection model as to how the Colorado River might have crossed the Kaibab arch. • Cenozoic geomorphic evolution of the Colorado River, Colorado Plateau • Geology of central Colorado Plateau as it relates to the origin of Grand Canyon • Why the Colorado River reached the mouth of Grand Canyon at 5.5 Ma • How the Colorado River turned west and crossed the Kaibab arch high • A karst-connection model vs. a lake-overflow model for crossing the Kaibab arch [ABSTRACT FROM AUTHOR]

The relationship between landslide area and volume has been shown to obey to a power law with a scaling exponent α varying from 1.1 to 1.6. This paper presents a three-dimensional upper bound method of limit analysis to evaluate the scaling exponent for the power-law relationship between source area and source volume of incipient rotational failure in soils. Based on an ensemble of data from calculated 20,000 theoretical homogenous slopes, the relations between landslide area and volume are calculated on a statistical basis and two fitting forms are systemically analyzed. Form 1, which gives the area-volume relations directly, shows an excellent agreement with field observations, with the scaling exponent α equal to 1.40. Form 2, considering the soil materials, is more suitable for the analysis of landslides affecting artificial homogeneous slopes. Three kinds of failure surface geometries, i.e., deep, intermediate, and face failure are discussed. The parametric study illustrates that the failure surface geometry affects the scaling exponent within a limit range. Further, the proposed method reveals that if the hillslope inclination, internal friction angle, and hillslope relative width are determined, the geometry of the landslide shows self-similar behavior, otherwise, the behavior is self-affine. [ABSTRACT FROM AUTHOR]

Remote sensing-based tectonic geomorphology is widely applied to study neotectonic processes. This technique is relatively cheap and easy to apply, and it allows investigating large areas for tectonic activity. Existing literature comprises a variety of indices and techniques, seemingly able to work in almost all tectonic settings. In this paper we study a particularly challenging region in W Slovenia and NE Italy, characterised by slow deformation rates, high precipitation, dense vegetation, and intense modification of the landscape and drainage system due to karst processes. We apply a suite of well-established geomorphic indices including terrain ruggedness, surface roughness, hypsometric integral and analyses of drainage parameters, as well as several less commonly applied analyses, such as the assessment of doline density and doline geometry. The aim was to test the capabilities of the applied techniques at various spatial scales and to extract information about the active tectonics. We begin with broad, regional analyses to detect the morphological imprint of active faults in the landscape. Then, we perform detailed studies of selected sites and single faults. Finally, we analyse a polje located on the trace of an active fault in the highest detail. We then compare the different techniques and different digital elevation models regarding their usefulness for detecting tectonic influences on the karstic landscape. The results show that most of the well-established methods we tested are not suitable to detect even the largest, clearly active faults in the area. The resolution of the used DEMs also has a notable impact on the analyses. We conclude that it is almost impossible to identify active faults solely based on the used techniques. This is mainly due to the low deformation rates and to the intense karstification of the study area that leads to a disconnected surface drainage system. Additional problems arise from the strike-slip mechanism of active faulting. Lithological contrasts and inactive dip-slip faults can lead to false-positive signals of tectonic activity. However, some of our results also show a tectonic signal, indicating neotectonic strike-slip deformation with a notable dip-slip component. Remote sensing studies have demonstrated to be powerful tools for tectonic geomorphology studies, but low tectonic rate karstic landscape conditions as in W Slovenia/NE Italy push even the most trusted methods to their limits and highlight the importance of validation and ground-checks of the results. • Tests quantitative geomorphologic metrics to a challenging karstic study area • Investigates different spatial scales: regional, local fault traces, single polje • Lithology and karst control landscape, with metrics failing to detect active faults • Metrics less sensitive to fault activity than faulting mechanism • Using metrics to inform on active tectonics can fail in slow deforming karst areas [ABSTRACT FROM AUTHOR]

Subglacial processes influence the large-scale behaviour of glaciers and determine the geological processes that occur at the ice-substrate interface. In this paper we focus on subglacial deformation beneath a cold-based glacier resting on permafrost. We ask what are the drivers of subglacial permafrost deformation, how is strain distributed beneath glaciers with a permafrost substrate, how is strain transmitted from the glacier into the substrate, and how is deformed permafrost incorporated into the basal zone of the glacier? To address these questions a tunnel excavated in the margin of Wright Lower Glacier in the McMurdo Dry Valleys, Antarctica to observe the structure of the basal zone and bed of the glacier and to monitor basal ice deformation over a period of 4 years. The tunnel revealed a stacked sequence of stratified debris-bearing and clean ice layers, and thick rafts of frozen sediment. Isotopic and gas analyses reveal that despite the low local temperature of the basal ice (−18.5 °C), liquid water has played an important role in the formation of this basal sequence. The rafts of frozen sediment contain well preserved sedimentary structures and algae layers that show the material has been entrained from the underlying permafrost. Deformation measurements made with a combination of displacement transducers, strain arrays, and plumb-lines show that strain and motion within the basal zone are heterogeneous and that strain is transmitted through the permafrozen sediment and into intra-sediment ice layers. The distribution of strain in the basal zone produces a compound velocity profile resembling the deformation patterns inferred from deformation structures in Pleistocene permafrost and also resembles profiles associated with subglacial sediment deformation driven by hydrogeological processes. We conclude that ice-rich permafrost is readily deformed by glaciers and that there is no clear boundary between basal ice and deforming permafrost. [ABSTRACT FROM AUTHOR]

This paper presents geomorphic evidence for the significant role of surface-subsurface connectivity in the geomorphological evolution of tabular hills (mesas) capped by moderately thick sandstone beds. The study area is located in Central Europe, in the Sudetes mountain range (Poland, Czechia), in an area built of a clastic succession of Late Cretaceous age. Research involved analysis of high-resolution LiDAR DTM and its various derivatives, providing insights into characteristics of drainage routes and patterns of ruiniform relief, as well as fieldwork. The latter included landform recognition and mapping, surveying representative cleft and cave systems. Specific surface landforms indicative of drainage diversion underground and subterranean pathways of sand removal include boulder-filled troughs and hollows, open clefts and plazas, pseudo-sinkholes and tilted blocks. Further evidence is provided by abundant, joint-aligned roofed slots and boulder caves, whose origin is attributed to selective sandstone weathering, sand evacuation by groundwater, and gradual subsidence. Sandy cones and sheets below exits of slots and fractures are the complementary sedimentary evidence. The percentage of caprock area drained via subterranean outflow varies from 16 % to 89 %. Reasons for the high efficacy of subterranean water and sediment transport include both structural factors (regular jointing pattern, high porosity) and, very likely, pre-conditioning role of dissolution of cement in the quartz arenites (arenization), which facilitates detachment of individual grains even by low flows under low hydraulic gradient. Thus, the sandstone-capped mesas show numerous analogies to the karst proper, especially silicate karst. They are manifested in both similar landform inventories, main preparatory processes, and considerable surface-subsurface connectivity. • Strong surface-subsurface connectivity in ruiniform relief of sandstone-capped mesas • Inventory of landforms indicative of subterranean erosion in rock cities presented • High-resolution DTMs help to identify closed basins, sinks and concave landforms • Analogies to karst are both morphological and morphogenetic. [ABSTRACT FROM AUTHOR]

Channel planform is the result of present and past hydrologic, sedimentary, and geologic conditions, and represents an adjustment of fluvial systems to these conditions. An important yet overlooked aspect of planform diversity of rivers in intensively managed agricultural landscapes of the upper Midwest (USA) is the co-occurrence of single-thread meandering and multi-thread anabranching reaches. Recent work on the role of river corridors in critical-zone dynamics of intensively managed landscapes has revealed the existence of juxtaposed meandering and anabranching reaches, yet the prevalence of anabranching reaches within meandering rivers in the upper Midwest is unknown. In addition, the morphological characteristics of these reaches and whether the stream power domain of these reaches differs from that of meandering reaches are also unclear. This paper quantifies the prevalence, planform morphology, and stream power domain of anabranching reaches along numerous lowland meandering rivers in the upper Midwest. Anabranch prevalence is explored for five representative watersheds using Google Earth aerial imagery and airborne LiDAR data. Less than 1 % of the total stream length in these watersheds (∼42,000 km) exhibits anabranching, but no watershed is devoid of anabranching reaches. Most anabranching reaches are characterized by a two-channel looping configuration, although complex anabranches with more than three channels exist at a few locations. Mean bifurcation angles (70° ± 29°) of the anabranching reaches are higher than those of braided rivers (40°-60°), with maximum angles as high as 150°, whereas mean confluence angles (60° ± 28°) fall within the range of junction angles in stream networks (45°-75°). Stream power analysis indicates that the occurrence of anabranching reaches along meandering rivers in the upper Midwest is significantly related to local increases in channel slope. The stream power domain of most anabranching reaches in the upper Midwest falls within that of meandering rivers, although some reaches have power similar to that of braided or wandering gravel-bed rivers. When considered collectively, multi-thread reaches juxtaposed with meandering reaches do not fit neatly into existing classifications of anabranching rivers. • Anabranching occurs along only 0.38 % of total stream length in five watersheds in the upper Midwest, U.S.A. • The majority of anabranching reaches have a two-channel configuration. • Anabranching reaches in the upper Midwest have locally higher channel slopes than adjacent meandering reaches. [ABSTRACT FROM AUTHOR]

Cirques are typical erosional landforms of glaciers and have been used as bases for paleoclimate and paleoenvironment reconstruction and for understanding the interactions between glacial erosion, climate, and topography. The availability of high-resolution digital elevation models (DEMs) provides the opportunity to map large populations of cirques for regional and global scale analysis. However, cirque outlines are still mainly determined based on manual digitization, which is time consuming and labor intensive. This paper introduces an automated method to recognize and delineate cirques using DEMs based on a series of hydrological and morphological analyses, including delineating stream network, filtering streams, determining potential cirque threshold points, and delineating cirque outlines. A semi-automated tool is also developed based on user-specified threshold points or cross sections. The related tools are coded in python and imported into ArcGIS as a toolbox, AutoCirque, with user friendly interfaces. Comparison in a test area of the eastern Tian Shan, China, indicated that the population statistics are relatively consistent between manually digitized and auto-delineated cirques. Detailed comparisons for 11 selected cirques indicated that the AutoCirque-delineated and manually digitized cirque outlines are similar in shape with an average boundary offset of approximately one DEM cell size (30 m) and a 70–90% overlap-fit percentage. The derived cirque metrics are also similar, especially for elevation, slope, and aspect related metrics. This toolbox can significantly speed up the analytical processes, remove the subjectivity in delineating cirque outlines, and allow for the comparison of cirque morphology and metrics at regional and global scales. • This paper presents an automated method to delineate cirque outlines from DEMs. • The developed ArcGIS toolbox incudes both fully automated and semi-automated tools. • Delineated cirques have consistent population statistics with manual-digitized ones. • Manual- and auto-derived cirques are similar in shape with high overlap percentage. • This toolbox allows for large population analyses of cirques at different scales. [ABSTRACT FROM AUTHOR]

Dune dynamics and associated sedimentary fluxes have been estimated over a period of a week in the river Seine characterised by limited sediment supply. Distributed into two corridors, typical medium and small dunes associated with fluvial environments have been characterised from multibeam data acquired on four dates, 23-29 March 2021, after a limited peak flood. Dune morphometric parameters have been quantified on cross-dune 1 m spacing of bed elevation profiles and dune migration rates have been calculated by analysing successive multibeam acquisitions. Evidence of limited sediment supply conditions have been recognised from areas uncovered by mobile sediment in the troughs between medium dunes. Under such conditions, bedload transport associated with dune migration has been estimated using three methods: differential bathymetry, dune tracking and the Van Rijn empirical formula using a correction factor accounting for limited sediment supply conditions. The three methods provide similar bedload fluxes (less than an order of magnitude difference), and the small differences are related to input data uncertainties and the capability of these methods to capture sediment transport processes, such as sediment bypassing dunes. Based on field observations, this paper brings new constrains to the relationships between dune morphological parameters, migration rates and sedimentary fluxes and environmental parameters (sediment grain size, flow velocity and water depth) under limited supply conditions in a real river. • Dune morphologies and shapes are constrained by sediment availability • Limited supply of sediment restricts bedload transport associated with dune migration • Differential bathymetry captures a portion of suspended bedload bypassing dunes [ABSTRACT FROM AUTHOR]

The topographic ruggedness index (TRI) is widely adopted for the analysis of digital elevation models, providing information on local surface spatial variability. In this work, the TRI is interpreted according to a geostatistical perspective, highlighting its main characteristics and drawbacks. TRI can be interpreted as an omnidirectional short-range spatial variability index, computed according to a pixel centered perspective. The simplicity and interpretability of the index, free from user-dependent selections, promoted its implementation in several software environments and its application in a wide set of case studies. However, the index has several drawbacks for its application in earth sciences, such as a strong dependency on local slope (it is basically an average adjacent neighbor slope algorithm) and the selection of different lag distances in the computation of spatial variability along the main directions and the diagonal ones. We propose a new metric radial roughness index (RRI) in order to solve the main drawbacks of TRI but maintaining its main philosophy (i.e., pixel centered perspective and simplicity of the algorithm). The new index corrects for the differences in lag distances and resolves the dependency on trend using increments of order 2. The code of the index, implemented in R statistical language, and test data are provided with the paper (https://doi.org/10.5281/zenodo.7132160) to promote its implementation in other software environments. [ABSTRACT FROM AUTHOR]

The occurrence of earthquakes has the potential to significantly modify river morphology and cause notable effects on the aquatic ecosystem. Prior to the 2008 Wenchuan earthquake with a magnitude of 8.0, the Shiting River located in the upper basin of the Yangtze River was stable. Rapid bed incision or degradation has continued since the earthquake, and weirs and bank revetments were constructed to mitigate degradation. The impacts of channel morphology adjustment and human activities on biodiversity are not clear, which prohibits efficient river restoration. This paper evaluated the morphological quality of the Shiting River by employing the Morphological Quality Index (MQI), an approach recommended in the European Water Framework Directive. Macroinvertebrate diversity was analyzed in relation to the impacts of morphological adjustment and human activities based on field data collected in 2021. The results showed that the channel degraded and deepened after the earthquake, the planform changed from multi-threaded to single-threaded, and swamps on the floodplains disappeared. The quality of channel morphology in 2021 was evaluated using the MQI and was found to be ranging from poor to moderate. The diversity metrics of macroinvertebrates, specifically the Shannon, Simpson, and Evenness indices, exhibited a positive and significant correlation with four MQI sub-indices, which represented channel geomorphological functionality, artificiality, morphological pattern, and substrate, respectively. However, there was no significant correlation observed between the diversity metrics and the overall MQI score. The results imply that channels with superior morphological functionality, slower channel adjustment, and lower levels of anthropogenic disturbances tend to exhibit greater macroinvertebrate diversity. The study found a significant decrease in macroinvertebrate richness downstream of weirs and bridges. The community structures upstream and downstream of weirs and bridges were also significantly different. This study may help inform the ecological response of rivers to dynamic morphological changes and intense anthropogenic disturbances following disastrous earthquakes. • Post-earthquake channel morphological quality was poor to moderate. • Channels with higher morphological quality had higher macroinvertebrate diversity. • Morphology changes and human activities impacted macroinvertebrates. • Higher macroinvertebrate richness upstream of weirs and bridges than downstream. [ABSTRACT FROM AUTHOR]

The coastal mountain system (CMS) of southeastern China has been a natural place to study paleotopographic changes primarily due to its marked topographical contrast since the Late Cretaceous. For a quantitative reconstruction of the paleotopographic evolution of the CMS, this paper provides key information from along the Ningde–Jianyang and Huilai–Longchuan cross-sections using apatite (U-Th)/He (AHe) and zircon (U-Th)/He (ZHe) data combined with thermal history and paleotopographic modeling. For the Ningde–Jianyang section, the AHe dates are in the range of 44.3–70.8 Ma, and the ZHe dates are between 58.5 and 102.9 Ma. For the Huilai–Longchuan section, the resulting AHe dates are in the range of 37.9–73.8 Ma, and ZHe dates are between 65.5 and 119.7 Ma. The modeling results suggest that: 1) the CMS had an asymmetric topography during the Late Cretaceous with the SE segment being significantly higher (peak elevation = 3.8 km) than the NW segment (peak elevation = ~2 km). The marked decreases in elevation and relief of the CMS occurred during 80–40 Ma, followed by relatively minor topographic changes since ~40–30 Ma; 2) The SE segment of the southern CMS experienced significantly faster exhumation (~0.44 km/Myr) than northern CMS (0.16 km/Myr) during 70–60 Ma, which was probably related to thinning of the crust and orogenic collapse linked to the initial-rifting of the South China Sea; 3) The SE segment of southern CMS experienced slower exhumation than northern CMS during 60–40 Ma, likely resulting from the lower elevations in the southern CMS than in the northern CMS during 60–40 Ma. • The coastal mountain system forms a climatic boundary in southeastern China. • Thermochronological data collected along two horizontal transects. • Transect thermochronology results used for topography modeling. • Rapid exhumation from 70-60 Ma along the south 2-D transect linked to rifting. • Rapid exhumation from 60–40 Ma along the north 2-D transect linked to climate change. [ABSTRACT FROM AUTHOR]

Investigations comparing surface downwearing rates derived from photogrammetry data and the micro-erosion meters (MEM) are limited due to the former's coarse spatial resolution and the temporal scale of data collection. These space and time limitations were revisited with the possibility of simultaneously using the Structure-from-Motion (SfM) photogrammetric workflow and the MEM. Using a cross-scale nested survey approach over one year to cover micro (10−2 m2) and meso (100 m2)-spatial scales, this paper presents erosion rates on uplifted intertidal shore platforms and marine terraces at Kaikōura Peninsula, New Zealand. The survey represents one of the first investigations combining the MEM and the SfM technique to estimate erosion rates on horizontal coastal bedrock. In a unique way, we applied established methods which allowed comparative accuracy between models via similar point matching to provide a detailed representation and visualisation of the changing rock surfaces at similar spatial and temporal scales. Over one year, across a microscale area (~0.01 m2) of rock, the MEM and SfM point clouds (SfM PCs) measured the lowest and highest erosion rates on a similar rock type and erosion site. The mean annual erosion rate of 2.244 mm/yr from the MEM was lower than the rates of 2.608 mm/yr and 10.299 mm/yr estimated using the SfM micro- and mesoscale PCs, respectively. A lower range of erosion rates (0.131 to 4.750 mm/yr) was measured using the MEM compared to erosion rates estimated from the SfM microscale PCs (0.194 to 10.106 mm/yr). Across the mesoscale (1 m2) areas, higher erosion rates were recorded using the SfM mesoscale PCs on all but one erosion site showing that a significant amount of erosion was undetected by the MEM. Using the SfM-orthomosaics, we link the erosion rates measured across the micro and mesoscale areas to intense granular disintegration, flaking, micro- and polygonal cracking and biological activities. These results provide statistical evidence to argue against extrapolating MEM erosion data obtained over small areas to larger areas on shore platforms affected by recent tectonic uplift. The implications of these findings are considered within the context of techniques for measuring shore platform erosion across spatial and temporal scales. • Erosion rates were acquired at similar spatial and temporal scales using MEM and SfM • A significant amount of shore platform erosion was undetected by the MEM • SfM PC models provided higher mean erosion rates for the micro (~0.01 m2) and mesoscale areas (1 m2) • Statistically similar mean erosion rates across microscale areas support substituting techniques. • MEM efficacy at capturing maximum erosion across microscale areas on the Kaikōura shore platforms has diminished [ABSTRACT FROM AUTHOR]

Numerical modeling of landform evolution is the key to understanding the formation of land surfaces. However, landform evolution occurs under certain initial topographic conditions, while existing landform evolution models often use a plane or a randomly produced surface to establish the initial topographic conditions. This misunderstanding of the initial topographic conditions causes the landform evolution results to deviate greatly from the real terrain. Therefore, the initial topographic conditions must be reconstructed and integrated into the current numerical landform evolution model. In this paper, the Loess Plateau of China was selected as a typical sample area. The paleotopography was reconstructed and integrated into the numerical landform evolution model. Based on the evolutionary mechanism of loess landforms, modules of surface erosion, matter diffusion and precipitation were selected to construct a numerical model of loess landform evolution. Moreover, randomly produced terrain was used as the initial conditions during the landform evolution process and compared with the paleotopography-constrained evolution results. In addition, the results of the landform evolution process were evaluated with different terrain factors, and the uncertainty of the model was assessed by comparing different model conditions. The results show that, due to the control of paleotopography, the evolution results can maintain the main morphological structure of valleys in the loess landscape. Without considering the paleotopography, a large difference exists between the evolution results and the true ground terrain. These results show that paleotopography is an important feature of loess landform evolution modeling and is indispensable for reasonably expressing the process of landform evolution. Finally, the numerical modeling of loess landform evolution with the consideration of paleotopography can not only help to achieve a better understanding of the loess landform evolution process but also provide a reference for feature dependent landform evolution modeling in different landform applications. • Paleotopography affects the evolution of loess landform in the Loess Plateau. • We integrate the paleotopography into the numerical loess landform evolution model. • Our results can maintain the main morphological structure of loess landform. • Our research provides a reference for feature-concerned landform evolution modeling. [ABSTRACT FROM AUTHOR]

As one of the most densely populated areas in the world, the Pearl River delta has been well studied in its postglacial sedimentary stratigraphy and the effects of Holocene sea-level rise. However, the effects of fluvial force on its geomorphological evolution are much less understood. This paper analyzed the Holocene sedimentary archives and reconstructed the geomorphologic history of an area where the West and North Rivers join and enter the deltaic basin. The reconstruction is based on the analyses of particle size, total organic carbon, organic carbon isotope ratios and microfossil diatoms of five radiocarbon-dated core sediments. The results show rapid paleo-incised valley infilling since c. 9500 cal. a BP, in response to sea-level rise. During marine regression starting from c. 8000 cal. a BP, a bifurcation occurred, and a mouth bar was developed. While the mouth bar emerged to mean tide level around c. 5500 cal. a BP, the surrounding estuarine subtidal flats were gradually transformed into tidal wetlands by c. 3000 cal. a BP. The immediate adjacent waters to the mouth bar were gradually infilled from c. 3000 cal. a BP onwards which narrowed the distributary channels. This landform evolution in the head area of the Pearl River delta resulted in the gradually strengthening fluvial force and weakening tidal force since the relative sea level approached its stabilization. During the past 3000 years, the continuous strengthening of fluvial force supported the accretion of deltaic floodplains. The discovery of mouth bar formation, channel narrowing and deltaic floodplain accretion in this location brings a new perspective of scientific investigation to river delta geomorphologic evolution in response to natural and anthropogenic factors. • The first mouth bar and bifurcation of the Pearl River delta are identified. • Geomorphologic evolution of the mouth bar and delta plains are reconstructed. • Strengthening fluvial force played a key role in the development of the delta plain. [ABSTRACT FROM AUTHOR]

Determining effects of climate change on landscapes involves numerous uncertainties. This paper presents and illustrates a protocol for climate attribution of landscape responses. The major steps are ascertaining potential climate-related responses, establishing plausibility for a climatic influence, identifying alternative or additional causes, testing possible climate and non-climate causes, and interpreting the role of climate and climate change in the landscape response. The protocol is based on existing practice in the historical and interpretive branches of Earth and ecological sciences, and explicitly considers negative (non-confirmatory) results for climate and other factors. The protocol is applied to the conversion of brackish marsh to open water in the upper Neuse River estuary, North Carolina. Conversion since at least the mid twentieth century can be attributed to relative sea-level rise, driven primarily by general climate warming, with no supporting evidence for any additional or alternative drivers. The only other factor with supporting evidence is human modification in the form of ditches, around which conversion was concentrated, though marsh loss also occurred in unditched portions. Rapid recent marsh loss is attributable to Hurricane Florence (2018), particularly the storm surge. Weak positive inferential support exists for a role of climate change in the storm, but aspects of the storm's impact not linked to climate are more important for the marsh conversions. Overall, the landscape response can be linked to climate, exacerbated by direct human impacts of marsh ditching, and strongly influenced by local place factors and the specific storm track. Recent and ongoing climate change is a significant factor, but not paramount, in determining the landscape response. The Neuse River case study is not unusual—and is probably typical—in identifying a combination of climate and other factors strongly influencing landscape response. [Display omitted] • Attributing landscape responses to climate change presents numerous complexities. • Landscape response attribution protocol based on traditional geomorphic approaches • LRA protocol applied to recent conversion of estuarine marsh to open water • Marsh loss due to sea-level rise & major storm, but non-climate factors important • LRA protocol useful to identify & evaluate climate & non-climate drivers of change [ABSTRACT FROM AUTHOR]

Marine potholes are common features along rocky shore platforms from around the world. Their occurrence can be used as a palaeo-sea level indicator, however, little attention has been given to submerged marine potholes found on relict shore platforms below the depth limits of SCUBA (≤50 m). This paper examines (n = 238) anomalously large potholes found on a submerged aeolianite shore platform on the outer shelf of the Eastern Cape, South Africa. Using a combined ultra-high resolution seismic reflection, side scan sonar and multibeam bathymetry approach, together with remote observation vehicle dives, the pothole occurrences are mapped. Potholes are either individual or occasionally conjoined, form on sediment-free aeolianite platform and cluster mostly between water depths of 85–95 m. Their sizes are an order of magnitude larger than previously documented, and larger than their fluvial equivalents. Pothole strings are common, associated with the high points between NNW-SSE striking bedding planes of the aeolianite that crop out at the seabed. Potholes are often elongated and aligned with these bedding planes, or in a coast parallel fashion, associated with joints and micro-cliffs in the aeolianite. The potholes possibly formed during several slowstands or stillstands surrounding the Last Glacial Maximum (LGM, 25,000 to 20,000 yr BP) and the Bølling-Allerød interstadial (B-A, 14,500 yr BP). Given their sizes, we ascribe part of their development to chemical weathering of the platform, especially during the periods where sea spray could pond to form dissolution pans in the supratidal part of the aeolianite platform. A wet and warm B-A climate exacerbated chemical weathering, with karst processes initially dominant, followed by mechanical weathering with shoreline migration. Once submerged, only horizontal enlargement ensued. Geological contingencies (joints, bedding planes and platform lowpoints), modified by early weathering-dominant and later wave-dominant processes, were responsible for the evolution of the shore platform morphology. [ABSTRACT FROM AUTHOR]

In seismically-active regions, earthquake-induced landslides (EqIL) are likely to enhance slope denudation and sediment delivery both over short and longer terms, which might strongly condition landscape evolution in general. In mountain regions marked by a medium to high seismicity, co-seismic slope failures typically present a relatively low frequency but also high magnitude pattern which should be addressed accordingly within landslide hazard assessment, considering the already high frequency of precipitation-triggered landslide events. The Vrancea Seismic Region located in the curvature sector of the Eastern Carpathians (Romania) is the most active intermediate-depth seismic zones (focal depth > 70 km) in Europe. It represents the main seismic energy source throughout Romania with significant transboundary effects recorded as far as Ukraine and Bulgaria. During the last 300 years, the region featured 13 earthquakes with magnitudes (M w) above 7, out of which seven events had M w above 7.5 and three between 7.7 and 7.9. Apart from the direct damages, the Vrancea earthquakes are also responsible for causing numerous other geohazards, such as ground fracturing, groundwater level disturbances and deep-seated landslide occurrences (e.g. rock slumps, rock-block slides, rock falls, rock avalanches). The previous large earthquake-induced deep-seated landslides of the Vrancea region were found to affect the entire slope profile. They often formed landslide dams which strongly influenced the river morphology, posing a serious threat to human life and human facilities of the downstream rural communities through the imminent lake outburst floods. Despite the large potential of this research issue, the correlation between the region's seismotectonic context and landslide geomorphic predisposing factors has not been extensively documented and fully understood yet. Presently, the available geohazard inventories provide limited historical information to quantify the triggering role of seismic activity for observed slope failures across the Vrancea region. However, it is acknowledged that the morphology and geology of numerous large, deep-seated and dormant landslides of this region, which may be reactivated in future, with head scarps near mountain tops and located close to faults, in anti-dip slope conditions show significant similarities to the large mass movements with a proven seismic origin (such as in the Tien Shan, Pamir, Longmenshan, etc.). Thus, the relationship between landslide occurrences and the joint action of triggers and preparing factors (seismotectonic or climatic or both) needs to be investigated in more detail and further considered in the regional multi-hazard risk assessments. The purpose of this paper is to outline the current knowledge level of the landslide-earthquake relationship by accounting for the possible effects of the previous major earthquakes in the Vrancea region. The key findings contribute to the gain of the baseline knowledge for an improved assessment framework of multi-hazard (earthquake-landslide) risks, as required by the Sendai Framework for Disaster Risk Reduction (SFDRR). [Display omitted] • Vrancea earthquakes are responsible for causing landslides. • Vrancea seismotectonic-landslide context is not fully understood yet. • Numerous landslides show a typical seismically-induced morphology. • Deep-focal earthquakes are conditioning complex and distant landslides. • The research improves multi-hazard (earthquake-landslide) risk assessment. [ABSTRACT FROM AUTHOR]

The Orlickie-Bystrzyckie Mountains Block (OBMB) is a medium-size, transboundary morphostructure within the Sudetes range in Central Europe, subject to non-uniform uplift in the late Cenozoic. Geologically, it consists of Variscan basement and Permian to Cretaceous sedimentary cover. This paper attempts to unravel its morphotectonic history and decipher the spatial pattern of uplift and erosional response, using several complementary, quantitative approaches to characterize topography. The focus is on: (1) general relief properties captured by selected topographic variables; (2) fault-generated escarpments, which define the eastern and northern limits of the study area; (3) drainage patterns and its peculiarities; (4) diversity of longitudinal river profiles and valley morphology. A LiDAR-based high-resolution digital terrain model was the primary source of elevation data. An important component of the study was examination of the role of lithological diversity on relief properties. A statistical approach generally revealed a secondary role of the rock factor and provided a foundation to interpret the macro-topography of the OBMB in terms of tectonic controls. Based on geomorphometric characteristics and information about the distribution of sedimentary rocks, which can be used as marker horizons to identify vertical displacements, four major and one secondary centres of surface uplift have been recognized. They are all asymmetric, being bounded by distinct fault-generated escarpments on one side and sloping gently in the opposite direction. Erosional response to uplift has been variable and includes, apart from simple incision into rising crustal blocks, the origin of epigenetic-antecedent water gaps, drainage diversions, headward erosion, and captures. This study also reveals that morphometric indices routinely used to extract the tectonic signal from landform patterns do not necessarily provide consistent information. • Morphostructural complexity of a large tilted block revealed from landform analysis. • Major and secondary centres of uplift are recognized. • Various erosional responses inferred from drainage patterns and valley morphology. • Rock factor demonstrated to be of secondary importance in relief evolution. • Interpretation of numerical indices may be equivocal. [ABSTRACT FROM AUTHOR]

Riverine source bordering dunes are formed by the interaction of fluvial and aeolian processes. Even in humid regions such as central Japan, small-scale, elongated aeolian dunes parallel to river channels occur intermittently; a typical example is identified where sand bars had formed along the left bank of the lower reaches of Kiso River. This paper presents the sedimentary characteristics and luminescence chronology of the aeolian dunes along the Kiso River. The sand constituting dunes is well-sorted, medium-grained and the grain size shows little variation with depth. The sand would be supplied from the riverbed via the bars by the strong west-northwesterly to westerly winds promoted by the monsoon in the dry winter when the water level of the Kiso River drops significantly. Fading corrected infrared-stimulated luminescence (IR 50) dating suggests that the dunes occurred and grew rapidly upward after about 600–700 yr ago. Increased sediment yield caused by human activities such as deforestation in the drainage basin, and the resulting increase in sediment supply to the lower reaches may have promoted the formation of dunes. However, with the construction of continuous levees, the reduced sediment supply related to dam construction, and the lowering of the riverbed, the connectivity between sand bars and dunes declined, and most of the dunes appear to have been stable for the past century. Fluvial sand supply influenced by human activities as well as strong winds during the dry season plays a crucial role in the formation of riverine source bordering dunes in humid regions. [ABSTRACT FROM AUTHOR]

In this paper, we retrace the geomorphological evolution of a 6.5 km-long segment of the Blanco Este River, which drains the Calbuco volcano in southern Chile, highlighting the geomorphic signatures of the disturbances caused by the 1961 and 2015 eruptions. In particular, we track the geomorphological changes and the evolution of the geomorphological units and discuss the underlying processes. In addition, we use the NDVI (Normalize Difference Vegetation Index) to characterise the vegetation recovery at the basin and the active channel scales. The reconstruction of the geomorphological changes is performed by means of photointerpretation and supervised classification image analysis. Moreover, we quantify braiding indices and active channel widths to characterise the fluvial corridor and to describe its evolution after the two eruptive events. It is found that the evolutionary trajectories of the Blanco River immediately after the eruptive events of 1961 and 2015 exhibited strong similarities. In fact, the major geomorphological adjustment of the Blanco Este River occurred during the first period of observation (19 years) after the 1961 eruption. Subsequently the river progressed gradually towards an advanced relaxation stage in 2014. For 53 years (between 1961 and 2014), the reduction of the active channel width was the dominant process, followed by erosion, which favoured the regeneration and consequent expansion of vegetation cover within the river corridor. The 2015 eruption reset the fluvial landform and a new cycle of sedimentation, braiding and formation of central bars began; the highly dynamic pattern is still observed today. [ABSTRACT FROM AUTHOR]