Earth Surface Processes and Landforms最新文献

New technology allows the reconstruction of postmining landforms using geomorphic design principles. It is important that such designs be evaluated and if needed, redesigned or reshaped so that soil loss is minimised and to ensure the landscape is geomorphically and ecologically integrated with the surrounding landscape. One tool to assess geomorphic landforms is to use a computer-based landscape evolution model (LEM). LEMs allow different designs to be input and will highlight where erosion will occur and type of erosion (i.e. sheetwash, riling, gullying) as well as erosion rate. At the Santa Engracia abandoned mine (East-Central Spain), postmining landscapes were designed using geomorphic principles (GeoFluv method and Natural Regrade software) and later constructed. The SIBERIA LEM was used to assess the erosional behaviour of these landscapes. Using suitable topsoil, vegetation and an organic blanket reduces erosion, and if vegetation can be established, the modelling demonstrates minimal gully erosion. The erosion forecast (5.3 to 6.3 t ha⁻¹ year⁻¹) is significantly lower than the initial surface (~350 t ha⁻¹ year⁻¹) using conventional (terraced) mine restoration. The predicted erosion rates and gullying are less than for the unmined (natural) Alto Tajo environment. Importantly, with the ability to spatially forecast gully location, erosion reduction measures can be undertaken. The method described here provides a robust assessment procedure and highlights the potential strengths and weakness of a design therefore supporting lower cost construction and repair with a higher chance of restoration success. The combination of geomorphic landform design and assessment using a LEM for this project (LIFE RIBERMINE) presents a new standard for mine rehabilitation in Europe.

Electric resistivity surveys in karst environments are commonly employed to establish parameters that can help in the evaluation of collapse risk related to sinkhole or cave formation. However, these surveys are often executed from the surface with consequent limits in resolution and identification potential as a function of coverage thicknesses. Application of these methodologies directly inside known caves, for a better understanding of their formation mechanisms, is uncommon due to accessibility problems, the nontrivial referencing issues that arise when operating in an underground environment and the challenging 2D/3D interpretation issues emerging from the presence of the cavity itself. This paper reports on the application of electric resistivity tomography along with specific geological and topographic mapping, inside the Borna Maggiore di Pugnetto karst collapse cave. Comprehensive knowledge of this cave, developed in mica-rich and carbonate-rich calcschists, is problematic with traditional investigations, due to the cave breakdown that masks its structure. In this study, the 3D geometry of the cave is reconstructed using a topographical survey. This reconstruction is then utilised to perform a 3D inversion of the electrical resistivity tomography (ERT) dataset. The results of both 2D and 3D inversions are compared and discussed, focusing on the survey's ability to identify resistivity anomalies within the 3D volume surrounding the cave. Additionally, an open-source script is provided to facilitate the replication of this 3D modelling and inversion in similar underground contexts. Results of the paper show the effectiveness of the proposed surveys in the delineation of genesis and actual structure of the cave. The paper also proposes a methodological approach that can be adopted in similar contexts to enhance the understanding of speleogenesis.

The Rhoen Mountains, a relict periglacial landscape in central Germany, feature a wide range of openwork block accumulations. Although located in a temperate climate, those have characteristics comparable with cold regions of higher altitude or latitude such as arctic-alpine species, longer lasting snow patches or the discussed existence of summer or even year-round ice lenses in one of the largest of these landforms in the Central German Uplands. This study aims for a characterization of the microclimatic conditions of two neighbouring block accumulations. Therefore, temperatures were registered by data loggers along profiles, and snow dynamics were monitored using time-lapse cameras and terrestrial laser scans. These observations are finally compared with geophysical measurements to address the question of potential isolated low-altitude permafrost occurrences. Mean ground surface temperatures show an inverse thermal gradient along the Schafstein block accumulation. Furrows were identified as the cold spots in winter, whereas snow melt holes are signs of a chimney effect. In summer, cold air flows out at ventilation holes along the front causing temperatures of up to 25°C below air temperatures, although no clear signs of permafrost were detected. Temperature correlations reveal periods indicative of a recurring internal summer air circulation. Coarse blocky substrate also favours ground cooling of the smaller Mathesberg block accumulation compared with its surroundings. Winter temperatures are influenced by a persistent snowbank forming due to drifting and blowing snow at the leeward edge of a plateau as little amounts of snow are sufficient to be redistributed by westerlies. The prolonged melt of the snowbank might have had or still has a local hydrological and geomorphological impact. Uncertainties remain regarding the behaviour of the microclimate of block accumulations in a warming climate. Being ‘cold spots’ of high ecological value further investigations are suggested.

Slow-moving landslides play important roles in the landscape evolution and hazards planning. Studies along some strike-slip faults have shown that the geological structures and bed-rock lithology significantly contribute the distribution of slow-moving landslides. However, controls on the distribution of slow-moving landslides are poorly constrained in active orogenic regions, hindering our understanding of its role in the rapid orogenic process. The Hazara Kashmir Syntaxis in Pakistan is such a prominent geological structure of lesser Himalaya, where the inventory of slow-moving landslides is scarce. Here, we attempt the interferometric synthetic aperture radar phase-gradient stacking coupled with a deep-learning system to provide the first slow-moving landslides inventory (1066 presently active landslides, 2016–2023) in the Hazara-Kashmir region. Along with optical imagery and field investigations, we analyse the impacts of fault structures, bed-rock lithology, topography along with spatial distribution of earthquake and precipitation on the distribution of these slow-moving landslides. We find that 33% of the detected slow-moving landslides are distributed within 1000 m to active faults, and show a decreasing trend moving away from fault zones. This pattern strongly suggests that the active thrusting faults in this region significantly controls the distribution of slow-moving landslides, while topography and precipitation show less impacts. Our study reveals the spatial distribution of slow-moving landslides in a tectonic complex region with rapid orogenic process, and thus shows potential implications in geomorphology modelling and hazards evaluation for many less-monitored, contemporary uplifting high-mountain regions.

Due to their genesis, volcanic rocks present some singularities that make their geotechnical characteristics significantly different from other, more common types of rock masses, such as sedimentary and metamorphic rocks. The formation mechanisms of volcanic rocks are varied, rapid and generally high energy. These processes give this type of rock geotechnical behaviour and geomechanical properties that are completely different from those of nonvolcanic materials, due to their high heterogeneity and anisotropy. In volcanic rock slopes, applying widely used geomechanical classifications to assess the quality of any rock mass present several challenges due to their distinctive and singular characteristics, which detract from their validity. For this reason, the Center for Studies and Experimentation of Public Works (CEDEX) of the Ministry of Public Works, under the agreement signed with the Ministry of Public Works and Transport of the Government of the Canary Islands, carried out during 2017 and 2018 an exhaustive analysis and reviews of existing geomechanical classifications and their applications to volcanic terrains. They developed a new geomechanical classification called VSR (volcanic slope rating), based on data obtained from 85 slopes across the Canary Islands, which allowed for the estimation of the stability of volcanic rock slopes by evaluating seven geotechnical parameters. This article presents the work conducted to review and calibrate this tool, based on the study of 94 slopes of different lithotypes throughout the Canary Islands (lavas, pyroclasts, heterogeneous), culminating in the proposal of a new classification for pyroclastic massifs (with new parameters and different weightings) and the adjustment of the current classification for the other slopes (regarding the Surface Regularity parameter). Therefore, the VSR geomechanical classification was applied to assess the stability of these 94 slopes, revealing a strong fit for Types A and C (R² > 0.97), while the tool overestimated stability in Type B slopes, prompting a new classification proposal for this category.

An attempt is made in this study to advance the understanding of the sand movement on Mars by studying the bedform migration at Gale, Jezero and Pasteur craters. The study on the grain size distribution at Gale Crater using Curiosity rover (MAHLI and APXS) observations reveals that the grains with smaller diameters (~50–150 μ) are more prone to migration and vice-versa, which gives an idea of the necessary requirements that initiate bedform migration. The chemical analysis of the surface materials at the Gale crater revealed elevated concentrations of P₂O₅, SO₃, Cl and Zn in soil compared to sand and active transportation processes for sand but not soil. The comprehensive chemical makeup of the Martian soil (inactive bedforms) and sand (active bedforms) is characterized by its basaltic nature, with enriched volatile elements such as sulphur, chlorine and zinc, and the presence of minerals like plagioclase, pyroxene and olivine due to the cohesive nature of inactive bedforms. Physical weathering and wind flow velocity play a pivotal role in the formation of different sedimentary bodies, impacting grain size distribution and mineralogy. The effect of dust-lifting on surface features is studied by analysing Perseverance-MEDA observations at the Jezero crater to understand the short-term changes in the bedform. These events are found to involve the redistribution of only a small amount of materials and, thereby, changing surface features on Mars over a short period. To detect the bedform migration in the Pasteur crater, several HiRISE images acquired over different time intervals were used. The changes in the ripple crest (~0.29–1.18 m/Earth year) and dune slip face suggest new grain flow events. In the Pasteur crater, extensive changes in sand deposits near the dunes signify a widespread bedform migration. The stronger north-westerly and north-easterly winds dominate these changes. Thus, the bedform migration in the three tropical craters exhibits significant variability driven by localized aeolian processes. This variability is crucial for understanding Mars' geological history, current surface dynamics and eventually, helps in planning future missions.

Saltating particle tracking (SPT) is an essential visualized channel to understand the dynamics of aeolian saltation at sand particle size scale, while the published SPTs could have low recall or accuracy rate and misestimate further saltation intensity. Hence, a Kalman filter-Hungarian algorithm with a postprocessor (KF-H-k) was proposed, where the Kalman filter was employed for predicting particle motion, and the Hungarian algorithm for optimizing global assignment, as well as the postprocessor with k-means cluster for correcting the erroneous recovered tracks by Kalman filter-Hungarian algorithm. The new SPT was validated in a digital high-speed video with various particle concentrations from a wind tunnel experiment. It demonstrated that compared with the previous SPTs, KF-H-k kept the highest and most stable accuracy (85% ~ 93%), the best spatial resolution, the moderate recall rate (50% ~ 70%) and time cost. The present work offers a new hybrid scheme for tracking sand particles accurately but alsodatasets for automatically identifying saltating tracks via machine learning models, very critical for insight into new hypothesis on sand ripple formation.

Earthworks such as earthen berms have been constructed across the western US since the late 1800s to mitigate erosion in landscapes where water is both the dominant driver of erosion and the limiting resource for biota. Berms alter hydrologic, geomorphic and ecologic processes by intercepting runoff and altering patterns of water availability in the landscape. Understanding site-specific changes in process dynamics requires accurate mapping of berm locations and knowledge of their condition. This paper presents an automated, object-based framework for identifying earthen berms from 1 m LiDAR-derived digital elevation models in the western US rangelands. Geomorphon, a computer vision tool, was used to classify landforms and identify berm-like landforms, including summits and ridges. Ten geomorphic and geometric attributes associated with each potential berm object were used to develop a machine-learning model for distinguishing berms from natural summits and ridges. The model was trained and applied to independent test sites to identify and map berms. The mapped berms were compared with manually identified reference berms for accuracy assessment. The identification results achieved 79% to 87% recall, 82% to 92% precision and 81% to 89% F-measure. We also explored the influence of training sample selection on model performance and conducted an analysis of attribute relative importance. The automated framework has the potential to be scaled up to larger areas in semi-arid environments.

In this study, we present a synthetic model summarising the main sedimentary and morphologic factors that drive spatial–temporal variations in bank stability through an exemplar macrotidal estuary. In contrast to previous studies that tend to only consider localised variations in the stability of small-scale banks, here the focus is on understanding the bank stability patterns at the scale of the whole Severn Estuary (UK). The results show that during falling tides, the bank sediments persist in a near-saturated state giving elevated bank pore pressures that coincide in time with declines in the hydrostatic confining pressure, leading to destabilisation of the bank. In contrast, bank stabilisation predominantly occurs during rising tides when the hydrostatic confining pressure is able to dominate over the destabilisation processes. Cohesive macrotidal estuaries similar to the Severn Estuary, tend to present a generalised decrease in the instability moving from the outer estuary where the tidal oscillations are more significant, to the inner part of the system where such oscillations are reduced and coupled with less high banks.

Controlled experiments on natural forms involve a traditional view of explanation that prioritizes control, manipulation and replication over more nuanced understanding of the phenomena under investigation. This is an issue if the phenomenon, like tafoni, is historically contingent. In particular, the entanglement of the environment is explicitly severed in controlled experiments. The failure to adequately reproduce the ordered forms associated with tafoni in laboratory experiments suggests that simulation and field case studies could provide a more informative route to understanding tafoni. This will, however, require a more systematic recognition of how such research enables researchers to understand the initial conditions of weathering and modes of development to tafoni observed.