The destabilization and catastrophic failure of landslides triggered by retreating glaciers is an expected outcome of global climate change and poses a significant threat to inhabitants of glaciated ...mountain valleys around the globe. Of particular importance are the formation of landslide‐dammed lakes, outburst floods, and related sediment entrainment. Based on field observations and remote sensing of a deep‐seated landslide, located at the present‐day terminus of the Great Aletsch Glacier, we show that the spatiotemporal response of the landslide to glacier retreat is rapid, occurring within a decade. Our observations uniquely capture the critical period of increase in slope deformations, onset of failure, and show that measured displacements at the crown and toe regions of the landslide demonstrate a feedback mechanism between glacier ice reduction and response of the entire landslide body. These observations shed new light on the geomorphological processes of landslide response in paraglacial environments, which were previously understood to occur over significantly longer time periods.
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Climate change affects glaciated areas worldwide. Hazards associated with catastrophic landslides in recently de‐glaciated valleys increasingly affect human society and critical infrastructure. Our study provides new insights in the interaction between deglaciation and rock slope response and is important for both scientific and practical reasons. We show that critically unstable slopes are sensitive to glacier ice loss, the slope response is significantly faster than previously reported, and landslide response brought on by rapid deglaciation may be enhanced as a result of climate change.
Key Points
Critically stressed slopes are highly sensitive to glacier ice volume loss
Landslide response is rapid upon reaching a threshold of glacier ice loss
Rapid deglaciation due to climate warming may enhance occurrence of slope destabilization
The highly fissile lithology of the rockwalls and the diversity of mass‐wasting processes provide a specific character to the active talus slopes of the northern Gaspé Peninsula since deglaciation. ...At a regional scale, the geology of the rockwalls, the patterns and modalities of deglaciation and the evolution towards a cold temperate morphoclimatic regime in a maritime context still influence the geomorphological dynamics of scree slopes today. At a local scale, the south–north orientation of the main coastal valleys influences insolation and exposure to prevailing winds, which in turn influence the snow cover regime and the occurrence of freeze–thaw cycles. The statistical analyses carried out from the mapping of 43 talus slopes and their geometric variables allowed the identification of significant environmental factors for the characterization of the dominant geomorphic processes: snow avalanches, frost‐coasted clast flows, debris flows and rockfalls. Slope aspect appears to be a key parameter in the nature of the processes acting on the talus slopes. East‐ and north‐facing talus slopes are generally covered by a significant snowpack in winter and the dominant processes are snow avalanches and debris flows. West‐ and south‐facing talus slopes face prevailing winds and insolation and are subject to frost‐coated clast flows, the main driver for forest regression, and rockfalls. However, the evolution of scree slopes in forested environments remains extremely complex due to the multiscale components that affect their evolution in the short, medium and long term.
Statistical analyses carried out from 43 talus slopes and their geometric variables allowed the identification of environmental drivers for geomorphic processes. Slope aspect appears to be a key parameter in the nature of the processes acting on scree slopes: East‐ and North‐facing slopes are covered by a significant snowpack in winter, and the dominant processes are snow avalanches and debris flows. West‐ and South‐facing slopes face prevailing winds and insolation and are subject to frost‐coated clast flows and rockfalls.
Loess regions face significant challenges in quantifying hydrological processes and assessing geological environmental risks due to the prevalent development of preferential pathways and the ...limitations of existing monitoring technologies. To advance this knowledge, this study presents an improved electrical resistivity tomography (ERT) device, specifically designed for loess moisture observations. By refining the testing principle, power supply mode, and data collection method within the existing ERT framework, the new device offers unmanned operation, automatic data acquisition, remote transmission, and cost efficiency. It effectively tracks water movement and groundwater level fluctuations across various hydrological conditions, supporting long-term online monitoring of hydrological processes of loess slopes. Through the analysis of monitoring data and classification of 12 observed preferential flow types, water movement in loess systems can be generalized into four general patterns: uniform infiltration, preferential infiltration, inflowing diffusion, and lateral flow. This generalized scheme provides a simplified modeling approach for other researchers to quantify slope hydrodynamics and to assess geological safety risks involving preferential flow. Based on these insights and field investigations, a conceptual framework is proposed to elucidate the seepage-structure synergistic initiating mechanism of loess landslides. This framework suggests that water entry and movement patterns within the slope depend on the slope geological structure related to preferential pathways and the prevailing hydrological scenarios. Landslide occurs as the result of the progressive failure and reciprocal evolution between the slope hydrological environments and geological structure, which may also pose potential eco-hydrological risks. The outcome advances the development of slope hydrological monitoring technology and enhances the understanding of water movement laws and the associated geological environmental risks in loess slope systems, which is of vital importance to the early warning methods of loess landslides that account for preferential flow and for theoretical modeling of preferential flow in related disciplines.
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•An improved-ERT system is developed for long-term monitoring of slope hydrology.•The 12 preferential flow types observed in the loess slope landscapes are presented.•Four general patterns representing water flow in the loess system are proposed.•A framework for landslide seepage-structure synergistic processes is planned.
Mooring data collected on the continental slope of the South China Sea show that along‐slope deep sea bottom currents are generated when large spring internal tides (internal waves with tidal ...frequency) are observed, with the maximum velocity amplitude exceeding 0.15 m/s. The observations are consistent with predictions that near‐bottom breaking of internal waves can result in generation of along‐slope flows when these waves obliquely approach the slope. A linear internal tide model in one horizontal dimension with realistic topography and stratification is used to show that the breaking of internal tides is likely due to near‐critical reflection on the slope. Combining the mooring observations and the model simulation, an along‐slope near‐bottom transport of ~0.5 Sv is estimated. Along‐slope bottom flows caused by breaking internal waves potentially provide a significant way to deform continental slopes and affect deep water exchange between the marginal sea and open ocean.
Key Points
Internal tides are often obliquely incident to continental slopes
Internal tides break at near‐critical bottom slopes
Along‐slope deep currents can be generated by breaking internal tides
The heavy rainfall induced by global warming has increased the risk of landslides. Eco-friendly approaches, such as employing vegetation, prove effective in satisfying the requirements of both ...engineering and environmental considerations in slope engineering. The research aims to comprehensively assess and compare the environmental, economic, and slope stability of new stabilization methods, including vegetation cover, in comparison to conventional approaches such as anchorage and nailing. The research initially explored the stability of slopes in various geometries, identifying areas prone to slope failure. Subsequently, slope stabilization designs were implemented using three methods: vegetation, nailing, and anchoring. To enable a comprehensive comparison from environmental and economic perspectives, both life cycle assessment and life cost assessment were conducted. According to the results, employing vegetation proves effective in stabilizing slopes at lower heights, particularly up to 8 m, leading to a negative carbon emission attributed to photosynthesis, reaching up to −249 kg CO2. In the mid-angle range (30°≤ θ ≤ 60°), anchoring emits less carbon dioxide than nailing due to fewer elements. As the slope angle is increased, the nailing method becomes preferable to the anchoring method due to its use of materials and equipment with lower carbon emissions. During slope stabilization through nailing and anchoring, cement and steel emerge as the primary contributors to carbon emissions. Vegetation stands out as the most cost-effective slope stabilization option, with costs potentially reduced by 250% compared to conventional methods. Based on this research, vegetation emerges as an eco-friendly and cost-effective alternative for slope stabilization in particular conditions where plants effectively ensure stability. Decisions regarding the use of anchoring or nailing can be made based on environmental and economic aspects, considering the slope geometry.
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•Vegetation provides stability to a range of slope heights vs. angles and absorbs CO2.•Vegetation can be an alternative to conventional methods under certain conditions.•Nails emit less CO2 than anchors at steeper angles and higher heights.•A nailed slope is more cost-effective than an anchored slope in all geometries.•Cement and steel are the most CO2 emission sources of nailed and anchored slopes.
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•Optimal LS-factor formulas selected for soil erosion calculation using RUSLE.•Optimal L-factor and S-factor formulas calculate soil erosion with 5.55% RE.•RUSLE-Cal model constructed ...to auto-calculate soil erosion using five methods.•A suitability selection table of LS-factor provided to improve accuracy of RUSLE.
The slope length and slope steepness factor (LS-factor) formula in the Revised Universal Soil Loss Equation (RUSLE) has a considerable level of uncertainty due to the existence of multiple methods. In this study, four commonly used formulas for the slope length factor and two formulas for the slope gradient factor were chosen and combined based on their applicability to the specific research context. Based on the ModelBuilder in ArcGIS Pro 3.0, a RUSLE calculation model (RUSLE-Cal model) was constructed in the study, which can automatically calculate the soil erosion modulus using four commonly used RUSLE formulas and one combination formula. Taking the Fengyu River watershed in China as a case study, this research analyzes the uncertainty of different LS-factor formulas and validates the accuracy of RUSLE simulation results using measured sediment data. The optimal combination of LS-factor formulas is selected, and an in-depth analysis is conducted on the origins and suitability of each formula. The accuracy validation results indicate that, for the Fengyu River watershed, the optimal combination of L-factor and S-factor formulas were determined based on the slope gradient. Specifically, L1 formula was used when slope ≤ 10°, and L3 formula was used when slope greater than 10°. Similarly, S1 formula was used when slope ≤ 18°, and S2 formula was used when slope greater than 18°. The RUSLE model achieved the best simulation results with a relative error of 5.55%. The results of the uncertainty analysis indicate that the four formulas have a significant impact on the simulated soil erosion, with a RE ranging from −99.18% to 31.49%. Therefore, based on literature review and formula analysis, a suitability selection table for L-factor and S-factor formulas is provided, which can provide formula basis for the improvement of soil erosion in watershed models.
Landslides are a ubiquitous hazard in terrestrial environments with slopes, incurring human fatalities in urban settlements, along transport corridors and at sites of rural industry. Assessment of ...landslide risk requires high-quality landslide databases. Recently, global landslide databases have shown the extent to which landslides impact on society and identified areas most at risk. Previous global analysis has focused on rainfall-triggered landslides over short ∼ 5-year observation periods. This paper presents spatiotemporal analysis of a global dataset of fatal non-seismic landslides, covering the period from January 2004 to December 2016. The data show that in total 55 997 people were killed in 4862 distinct landslide events. The spatial distribution of landslides is heterogeneous, with Asia representing the dominant geographical area. There are high levels of interannual variation in the occurrence of landslides. Although more active years coincide with recognised patterns of regional rainfall driven by climate anomalies, climate modes (such as El Niño–Southern Oscillation) cannot yet be related to landsliding, requiring a landslide dataset of 30+ years. Our analysis demonstrates that landslide occurrence triggered by human activity is increasing, in particular in relation to construction, illegal mining and hill cutting. This supports notions that human disturbance may be more detrimental to future landslide incidence than climate.
Area‐slope scaling is an important tool for analysing geomorphic processes. In this study, we used hierarchical clustering to sort the area‐slope scaling data for both the numerical landscape created ...using the LandLab model and real landscapes. Random forest analysis was used to explore the effect of hierarchical clustering. We aimed to illustrate the heterogeneous features of area‐slope clustering and their influencing factors and to test whether they can be used to distinguish geomorphic domains. Our results showed that hierarchical clustering can easily detect the heterogeneous features of area‐slope scaling constrained by tectonic uplift and fluvial erodibility but not those constrained by the diffusion coefficient. The slope gradients over the inflection/transition zone of the colluvial and fluvial domains play a key role in identifying area‐slope scaling from different geomorphic domains. Case studies show that area‐slope scaling of clusters would be affected by different lithology and distance away from the trunk channel. In the high erosion circumstance, the fluvial process caused by tectonics leads to increasing slope gradients over whole geomorphic domains, as well as to retreating inflection between the colluvial and fluvial process domains. In low erosion circumstances or steady state, the fluvial process caused by nearby rivers cannot effectively change the slope gradients but can retreat the inflection. The real landscapes suggest that basins should be carefully selected for area‐slope scaling analysis to ensure that they are representative of the entire study area. Before geomorphological research, more basins of a specific research region need to be selected to conduct hierarchical clustering to select representative basins. Our study could be helpful in the identification of area‐slope domains, the extraction of geomorphic metrics and geomorphic process research.
A specific region with homogenous tectonic and climatic settings would have similar area‐slope scaling. Based on hierarchical clustering analysis, this study finds that hierarchical clustering can easily detect the heterogeneous features of area‐slope scaling constrained by tectonic uplift and fluvial erodibility but not detect those constrained by the diffusion coefficient. The slope gradients over the inflection /transition zone of the colluvial and fluvial domains play a key role in identifying area‐slope scaling from different geomorphic domains.
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