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Introduction: Landslide-dammed lake outburst floods (LLOFs) are common natural disasters in high-mountain regions, posing serious safety threats to residents' livelihoods and properties and causing major damage to engineering facilities. Giant landslides and river damming events commonly occur in the Eastern Tibetan Plateau in southwestern China. Dam failure generate LLOFs that form outburst deposits (ODs). This phenomenon is particularly common in some giant ancient landslide-dammed lakes. Methods: This study conducted a detailed investigation of the sedimentary characteristics of large-scale landslide-dammed lake outburst deposits in the Diexi Reach of the Upper Minjiang River and Tangjiashan Reach of the Tongkou River Basin, West Sichuan Plateau, China. Meanwhile, typical evidence of highenergy ODs was recorded. Results and Discussion: The longitudinal distribution of these ODs is similar to an elongated fan-shaped terrace along the river channel, presenting a distinctive sedimentary disordered -- sub-ordered -- ordered sequence from upstream to downstream. Several typical units of "sedimentary facies" are developed in the OD profiles, such as boulder units deposited by high-energy outburst flood (OF) events and the gravel and sand units representing pulsating-flow sedimentary environments during the recession stage. The grain size frequency curves are bimodal, and the granularity accumulated curves are upward convex, which reflect that the detrital characteristics of the sediment source area are mainly composed of coarse gravel and boulders. This indicates that the coarse gravel sediment gradually become decreased from upstream to downstream. Moreover, the OD hydrodynamic intensity displays a gradual weakening, and sediment sorting is improved. From upstream to the downstream, the mean particle-size and sorting of the ODs gradually decrease. The skewness become larger, and the kurtosis of the ODs is distributed in all the types. In addition, the different combinations of quartz sand surface microtextures indicate the transformation from high-to low-energy impacts over a short distance, which is controlled by flood hydrodynamics and regime. Significance: These sedimentary characteristics of ODs explain the hydrodynamic changes during the propagation of OFs, and are also important records for distinguishing between ODs, and "normal" floods. [ABSTRACT FROM AUTHOR]

Introduction: Landslide-dammed lake outburst floods (LLOFs) are common natural disasters in high-mountain regions, posing serious safety threats to residents' livelihoods and properties and causing major damage to engineering facilities. Giant landslides and river damming events commonly occur in the Eastern Tibetan Plateau in southwestern China. Dam failure generate LLOFs that form outburst deposits (ODs). This phenomenon is particularly common in some giant ancient landslide-dammed lakes. Methods: This study conducted a detailed investigation of the sedimentary characteristics of large-scale landslide-dammed lake outburst deposits in the Diexi Reach of the Upper Minjiang River and Tangjiashan Reach of the Tongkou River Basin, West Sichuan Plateau, China. Meanwhile, typical evidence of high-energy ODs was recorded. Results and Discussion: The longitudinal distribution of these ODs is similar to an elongated fan-shaped terrace along the river channel, presenting a distinctive sedimentary disordered-sub-ordered-ordered sequence from upstream to downstream. Several typical units of "sedimentary facies" are developed in the OD profiles, such as boulder units deposited by high-energy outburst flood (OF) events and the gravel and sand units representing pulsating-flow sedimentary environments during the recession stage. The grain size frequency curves are bimodal, and the granularity accumulated curves are upward convex, which reflect that the detrital characteristics of the sediment source area are mainly composed of coarse gravel and boulders. This indicates that the coarse gravel sediment gradually become decreased from upstream to downstream. Moreover, the OD hydrodynamic intensity displays a gradual weakening, and sediment sorting is improved. From upstream to the downstream, the mean particle-size and sorting of the ODs gradually decrease. The skewness become larger, and the kurtosis of the ODs is distributed in all the types. In addition, the different combinations of quartz sand surface microtextures indicate the transformation from high-to low-energy impacts over a short distance, which is controlled by flood hydrodynamics and regime. Significance: These sedimentary characteristics of ODs explain the hydrodynamic changes during the propagation of OFs, and are also important records for distinguishing between ODs, and "normal" floods. [ABSTRACT FROM AUTHOR]

Outburst floods can affect the survival adaptability of fish. Although the survival adaptability of many fish species under low steady-flow conditions has been studied, research on the survival adaptability of fish species under large outburst flood conditions is lacking. This paper takes the 2018 Baige landslide dam as an example. A breach model was developed to calculate the outburst discharge of the landslide dam. The outburst flood hydrograph is simulated with the breach model, which shows that the difference between the peak discharge of the dam break simulation results and the measured data is 0.13x104 m³/s. In addition, the simulated hydrographs are the same as the measured hydrographs. Furthermore, a two-dimensional fish habitat model was used to analyse the adaptability of Schizothorax to survival during the breaching process. For the survival adaptability of Schizothorax, we observed that as the flow rate increased the weighted usable area (WUA) decreased, which indicated a decrease in the adaptability of Schizothorax survival. In contrast, as the flow rate decreased and the WUA increased, the survival adaptability of Schizothorax improved. In addition, the WUA of Schizothorax changed with the substrate of the riverbed; the smaller the channel suitability index (CSI) the greater the WUA. This study revealed the impact of outburst floods triggered by landslide dam failure on the survival adaptability of Schizothorax, and a method for assessing the impact of outburst floods on fish habitat adaptability is provided. [ABSTRACT FROM AUTHOR]

Machine learning (ML) is increasingly utilized in Landslide Susceptibility Mapping (LSM), though challenges remain in interpreting the predictions of ML models. To reveal the response relationship between landslide susceptibility and evaluation factors, an interpretability model was constructed to analyze how the results of the ML model are realized. This study focuses on Zhenba County in Shaanxi Province, China, employing both Random Forest (RF) and Support Vector Machine (SVM) to develop LSM models optimized through Random Search (RS). To enhance interpretability, the study incorporates techniques such as Partial Dependence Plot (PDP), Local Interpretable Model-Agnostic Explanations (LIMEs), and Shapley Additive Explanations (SHAP). The RS-optimized RF model demonstrated superior performance, achieving an Area Under the Curve (AUC) of 0.965. The interpretability model identified the NDVI and distance from road as important factors influencing landslides occurrence. NDVI plays a positive role in the occurrence of landslides in this region, and the landslide-prone areas are within 500 m from the road. These analyses indicate the importance of improved hyperparameter selection in enhancing model accuracy and performance. The interpretability model provides valuable insights into LSM, facilitating a deeper understanding of landslide formation mechanisms and guiding the formulation of effective prevention and control strategies. [ABSTRACT FROM AUTHOR]