Search

Landslides and debris flows caused significant threat to the China-Pakistan Economic Corridor. This study introduced the spatial pattern of the relevant mountainous hazards and assessed the hazards risks, predicted the development trends, and proposed the relevant countermeasures as well. 584 landslides, 116 collapses, and 1669 mudslides in total were identified, which mainly distributed in the mountainous areas in the northern part of the corridor. The hazards were divided into five grades: extremely high, high, medium, low, and extremely low and the northern area is highly dangerous. The vulnerability assessment was carried out with traffic, economy, and population as indicators, and then the risk assessment results were comprehensively obtained. In general, the risk is higher in the northern part and lower in the southeast. In the future, as the intensity of earthquakes increases, the area of high-susceptibility landslides will gradually increase from 0.01% to 1.4% of the studied area, and these hazards are mainly distributed between the northern segment of Aikenert fault and Kazitaert fault, the northern segment of Miya fault and the central region of Bulunkou fault. According to the trend that rainfall and temperature increase, the susceptibility of debris flows in most river basins has increased. It is recommended to strengthen basic data collection and detailed investigation of key disaster points, and carry out early risk assessment and monitoring and early warning, while formulating emergency plans, which serves the safe construction of major projects along the Belt and Road. [ABSTRACT FROM AUTHOR]

[Display omitted] • The synthetic quantitative evaluation index system of community risk management capacity to debris flows is constructed. • Critical indicators include disaster prevention investment proportion, emergency skills diversity, and installed power capacity. • Public preference for prevention-oriented risk management patterns. • A participatory disaster management synergies framework is developed by examining sociodemographic and ethnocultural coupling effects. Disaster management often serves as the primary defense against ecological damage and threats to social well-being resulting from natural disasters. However, the quantitative research on unified disaster risk management capacity assessment has not been scrutinized. Based on the time series structure, this study proposes a novel framework and risk management contribution models for exploiting a community risk management capacity to debris flows (CRMCD) assessment system. A comprehensively improved method was utilized for indicator selection by combining R hierarchical clustering (RHC) and coefficient of variation methods (CV). Entropy-weighted grey correlation analysis (EGCA) and geographic information system (GIS) methods are employed to assign weights and visualize the disaster management capacity of research areas. Three risk management contribution models are constructed according to the criterion layers defined by CRMCD: prevention-oriented, emergency-oriented, and recovery-oriented. Furthermore, a questionnaire was designed by introducing multi-ethnic cultural scenarios to assess public risk awareness, avoidance behaviors, and management demands. A total of 3,060 survey samples were conducted among ethnic minority communities in Sichuan that issued debris flow disaster declarations in 2022. Social welfare and public satisfaction were examined to validate the applicability of the CRMCD assessment system and risk management contribution model. The results identified key indices contributing to enhancing CRMCD: The proportion of financial investment in disaster prevention and public security, Professional skills diversity of emergency responders, and Installed power capacity. The multinomial logistic regression analysis revealed public preference for the prevention-oriented type in the risk management contribution model, and interviewees demonstrated a more positive response regarding motivation and participation in disaster prevention under this model. Kruskal-Wallis H significance analysis highlighted that ethnic minorities and elderly populations exhibited lower levels of disaster knowledge reserves, avoidance awareness, and propensity to purchase disaster insurance. Unexpectedly, respondents with higher household income and education levels paid less attention to seeking assistance from professional community organizations. Disaster early warning emerged as a priority for respondents interested in strengthening community disaster management initiatives. Overall, this study outlines a systematic methodology to establish an objective index system and summarize management models, which provide breakthroughs in developing participatory disaster management frameworks and resilience communities. [ABSTRACT FROM AUTHOR]

By considering the integrity of microcosmic and comprehensive geomorphological features, this article intends to develop a quantitative method for regional risk assessment of debris flow by analyzing the in-depth relations among hazard-forming environments, disaster factors and elements at risk. Taking the debris flows in the Longxi River Basin in China as a case study, an approach based on the hydrological response unit (HRU) is proposed by establishing both a model and system for regional risk assessment to analyze the hazard of debris flows and the exposure and vulnerability of elements at risk. The HRU-based approach consists of 11 disaster factors: topographic slope; relative elevation difference; lithology; channel gradient; fault; disturbed area; rainfall; and the type, location, fragility and economic value of the elements at risk. Specifically, a hazard integrated model is built by considering the hazard factors and their corresponding weights to evaluate the hazard level of debris flow. Through determining the type, quantity, distribution, economic value and fragility of hazard-affected objects in a region, methods are established to determine the exposure and vulnerability of different elements at risk. Validated by using a field study of actual debris flows, a debris-flow risk map is obtained, and the assessment results are in accordance with the actual disaster situation. The analyses show that the distributions of zones with high risk and above (i.e., where hazard densities and economic activities are considerably high) are closely correlated with the topographic and socioeconomic characteristics of the debris flow catchment. These findings suggest that the assessment results provide scientific support for planning measures to prevent or reduce debris flow hazards; thus, the presented method may serve as a pertinent guidance for regional risk assessment of debris flows in both the Longxi River Basin and beyond. • Hydrological response unit (HRU) can sufficiently describe the comprehensive characteristics of geomorphology and hazard-forming conditions related to debris flow. • A factor system was quantified and built to analyze the in-depth relations among natural environments, disaster factors and elements at risk. • An HRU-based and quantitative approach for evaluating regional risk debris-flow effectively improves the reasonability and applicability of risk assessment of debris flows. [ABSTRACT FROM AUTHOR]

Mountain highways in China are located in various natural geographical areas with intense tectonic activity, steep topography and a high frequency of extreme precipitation events. These conditions make the highways vulnerable to the occurrence of multiple large debris flows simultaneously during heavy rainfall. To manage this hazard risk, a broader understanding of the hazard effects of debris flows and the vulnerability of highways is needed to reduce the losses resulting from these hazardous events. Accordingly, we analysed the effects of debris flow hazards on mountain highways and established an updated systematic indicator system to describe the vulnerability of highway infrastructure and movable hazard-affected objects. Next, we proposed a new integrated model of highway vulnerability based on the environmental sensibility, structural properties and functional effects of the highway infrastructure and on the exposure probability and quantity of movable hazard-affected objects. By analysing the characteristics of elements affected by debris flows, we developed a systematic and quantitative method of vulnerability assessment for mountain highways. Finally, this implemented method was applied to a case study in the Xiqu section of the Sichuan-Tibet Highway, an area seriously affected by debris flows during each rainy season. The hazard characteristics of disasters were analysed, and the affected highway sections were divided into four vulnerability levels. The analysis of the results indicated that the calculated vulnerability coincides with the actual effects of the disaster, which strongly suggests that the vulnerability assessment generated by the proposed method can serve as a pertinent guide for route selection, road rehabilitation and hazard mitigation of highways affected by debris flows in mountainous regions. [ABSTRACT FROM AUTHOR]

After the Wenchuan earthquake in China, debris flows have been more frequent. Multiple debris flows commonly occur in earthquake-affected areas during heavy rainfall, often causing losses of lives and property. We analyzed the dynamic movement of debris flows and proposed a quantitative method of debris flow hazard assessment, based on kinetic energy. Validated using field study of an actual debris flow disaster, these analyzes help determine the type, quantity, distribution, economic worth, and susceptibility of elements at risk. We established a method to determine vulnerability of elements at risk and we propose a systematic and quantitative method for local risk analysis of debris flows. We applied the proposed method to a debris flow in Qipan gully, which caused serious damages for Duwen Highway and Qipan settlements of Sichuan Province in 2013. With the support of a debris-flow movement numerical simulation, remote sensing, and GIS techniques, the proposed method analyzed disaster effects and divided the hazardous areas into three risk zones. Calculated risk zones coincided with the actual distribution and severity of damage of the event, suggesting that the risk assessment generated by the proposed method is consistent with results from the actual disaster. [ABSTRACT FROM AUTHOR]

Many mountain towns in China are located on the joint alluvial fans of multiple and adjacent past debris flows, making them vulnerable to large, multiple, and simultaneous debris flows during heavy rainfall. Without emergency management planning, such flows, often appearing with interconnecting and chain-reaction processes, can lead to extensive loss of life and property. In the Wenchuan earthquake-affected area, such disasters are common. We analyzed the compound effects of simultaneous debris flow events, and proposed three quantitative methods of debris risk assessment based on kinetic energy, flow depth, and inundation depth. Validated using a field study of actual debris flow disasters, these analyses are useful in determining the type, quantity, distribution, economic worth, and susceptibility of hazard-affected objects in a region. Subsequently, we established a method to determine the vulnerability of different hazard-affected objects, particularly concerning the susceptibility indexes of buildings or structures. By analyzing the elements underlying hazard formation conditions, damage potential, and the socio-economic conditions of mountain townships, we proposed a systematic and quantitative method for risk analysis of mountain townships. Finally, the proposed method was applied to a case study of Qingping Township, which was affected by 21 simultaneous debris flows triggered by a 50-year return period precipitation event. The proposed method analyzed the superposition and chain-reaction effects of disasters and divided the affected area of the township into three risk zones. The analysis indicated that the calculated risk zones coincide with the actual distribution and severity of damage in the debris flow event, which suggests that the risk assessment is consistent with results from the actual disaster. [ABSTRACT FROM AUTHOR]

The river-blocking effects of debris flows have become common in numerous catchments in response to climate and environmental changes, and these effects have caused multiple, overlapping, and interconnected chain reactions that have led to huge losses in alpine regions. Considering this issue, this article developed a quantitative method for the regional river-blocking hazard assessment of debris flows by analyzing the in-depth relations among river-blocking hazard formation processes, factors and evolution mechanisms. Taking the debris flows in the Parlung Zangbo Basin in China as a case study, a multidimensional analysis was performed to analyze the characteristics of the hazard sequence and its relationship with climate change, including changes in temperature and precipitation. Accordingly, a new step toward a more comprehensive hazard assessment is proposed by establishing both a model and a system for regional river-blocking hazard assessment to analyze the debris flow evolution processes and environmental dynamics. Specifically, the sources of loose material were quantitatively estimated by establishing mathematical models based on the geometrical characteristics of diverse moraines, and the debris flow runoff was scientifically determined by focusing on the analysis of moraine sources, the brittleness index of the sediment mass and the geomorphological connectivity. Next, through coupling with the hydrodynamic conditions of debris flows and river flows, methods were established to determine the blocking degree of debris flow hazards at the regional scale. Validated by a field study and a remote-sensing interpretation of actual debris flows, a debris-flow-induced river-blocking hazard map was obtained, and the assessment results were in accordance with the actual disaster situation. The analysis shows that the distribution of zones with high to very high levels of river blocking is closely correlated with the topographic characteristics and actual disaster sequences of debris flows. These findings suggest that the assessment results provide scientific support for engineering planning and hazard prevention in climate-sensitive areas; thus, the presented method may serve as pertinent guidance for regional river-blocking hazard assessments of debris flows in the Parlung Zangbo Basin and beyond. Unlabelled Image • River blocking by debris flow becomes sensitive to climate and environmental change. • Debris flow runoff was determined by dynamic source and morphological connectivity. • Relations in hazard-forming process were quantified by physical models and factors. • A new step is proposed to assess regional debris flow-induced river blocking hazard. [ABSTRACT FROM AUTHOR]