Analytic hierarchy process applied to landslide susceptibility mapping of the North Branch of Argentino Lake, Argentina

In the present study, we achieved the susceptibility mapping to slope instability processes by the implementation of Analytic Hierarchy Process and Weighted Linear Combination methods, in the North Branch of Argentino Lake, Southern Patagonian Icefield. The strong retraction of the glaciers in the area has triggered paraglacial readjustments, producing instability processes that favor the generation of mass removal processes. The results obtained from optical satellite images show that the highest degrees of susceptibility (4 and 5) are located on the western slopes of the Upsala Channel, Bertacchi and Cono Tributary Glaciers, and the Moyano and Norte Valleys, respectively. These slopes coincide with the geographic location of previous events surveyed by the inventory of unstable areas of the zone. Low degrees of susceptibility are found on the downhill valleys, outcrops rock and glaciers. The Consistency Ratio was 0.069, indicating that being less than 0.1 the study is reliable. The study sheds light on the knowledge of slopes and valleys that are more susceptible to processes of instability in mountainous areas, which would make it possible to prevent possible hazards associated with these events.Fil: Moragues, Silvana Noelia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lenzano, María Gabriela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lanfri, Mario. Comision Nacional de Actividades Espaciales. Gerencia de Coordinacion.; ArgentinaFil: Moreiras, Stella Maris. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Lenzano, Luis Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; Argentin

Risk management in Norwegian avalanche rescue operations. Managing uncertainty, complexity, overcommitment and the long-term monitoring of accident risk

PhD thesis in Risk management and societal safetyIntroduction: Avalanche incidents commonly take place in adverse environmental conditions, and the expected survival time of avalanche victims is short. These situations require an immediate rescue response, which may pose a serious challenge to the safety of both rescuers and avalanche victims. Historically, the Norwegian rescue service has experienced few serious accidents, but undesirable incidents where rescuers are dangerously exposed in avalanche runout zones seem more frequent. Risk management in the avalanche rescue service is multifaceted, influenced by its multi-organizational structure. Individuals acting in this socio-technical rescue system are easily caught between two imperatives: saving lives and staying alive. The aim of risk management is to maintain equilibrium in rescue commitment. This project analysed whether the Norwegian avalanche rescue system is correctly balanced to withstand the extra load of common risk influencing factors in rescue operations. Aim: The fundamental aim of this thesis was to contribute to new knowledge on factors that are important for risk management and performance in the Norwegian avalanche rescue service. Methods: Mixed methods research was applied to answer the specific research questions. This implied multiple research activities in a combination of quantitative and qualitative methodologies. Study number 1 was a retrospective study to characterize Norwegian avalanche incidents and rescue response (Paper I). A comprehensive study comprising avalanche rescue statistics, cross-case analysis, factor analysis and risk modelling was conducted to gain insight into avalanche rescue performance (Paper II). In a phenomenological study to explore the concept of overcommitment, nine air ambulance crews from five bases took part in focus group interviews (Papers III and IV). Lastly, a systemic safety analysis was conducted in two separate seminars, supported by the insight of six experts in Norwegian avalanche rescue operations (Paper V). The thesis itself is a cross-paper synthesis of results. Results: The studies returned results which contribute to justified beliefs about patient and rescuer safety in Norwegian avalanche rescue operations. Conclusion: A synthesis of results from the various studies indicates that the Norwegian rescue service is vulnerable to common risk sources in rescue operations, affecting the safety of both rescuers and patients. The avalanche rescue system could benefit from a focus on the integrity of already established safety barriers. This implies an interorganizational effort to identify and reach common goals and system requirements. This thesis may serve as input to discussions on risk acceptance levels in the rescue service, the applicability and validity of control algorithms in rescue management and how to adjust the degree of commitment in various rescue missions

ELECTRONIC REGIONAL RISK ATLAS: DEVELOPMENT, STRUCTURE AND APPLICATION PRACTICE IN REPUBLIC OF ARMENIA

Initially ERRA was developed as a web-service presenting natural (landslides, flooding, earthquake, wildfire, strong winds) and man-made hazards and risks

National-Scale Rainfall-Triggered Landslide Susceptibility and Exposure in Nepal

Nepal is one of the most landslide-prone countries in the world, with year-on-year impacts resulting in loss of life and imposing a chronic impediment to sustainable livelihoods. Living with landslides is a daily reality for an increasing number of people, so establishing the nature of landslide hazard and risk is essential. Here we develop a model of landslide susceptibility for Nepal and use this to generate a nationwide geographical profile of exposure to rainfall-triggered landslides. We model landslide susceptibility using a fuzzy overlay approach based on freely-available topographic data, trained on an inventory of mapped landslides, and combine this with high resolution population and building data to describe the spatial distribution of exposure to landslides. We find that whilst landslide susceptibility is highest in the High Himalaya, exposure is highest within the Middle Hills, but this is highly spatially variable and skewed to on average relatively low values. Around 4 × 106 Nepalis (∼15\% of the population) live in areas considered to be at moderate or higher degree of exposure to landsliding (>0.25 of the maximum), and critically this number is highly sensitive to even small variations in landslide susceptibility. Our results show a complex relationship between landslides and buildings, that implies wider complexity in the association between physical exposure to landslides and poverty. This analysis for the first time brings into focus the geography of the landslide exposure and risk case load in Nepal, and demonstrates limitations of assessing future risk based on limited records of previous events

Susceptibility Assessment of Single Gully Debris Flow Based on AHP and Extension Method

Debris flow mainly happens in mountainous areas all around the world with deadly social and economic impacts. With the speedy development of the mountainous economy, the debris flow susceptibility evaluation in the mountainous areas is of crucial importance for the safety of mountainous life and economy. Yunnan province of China is one of the worst hitting areas by debris flow in the world. In this paper, debris flow susceptibility assessment of Datong and Taicun gully near the first bend of Jinsha River has been done with the help of site investigation and GIS and remote sensing techniques. Eight causative factors, including slope, topographic wetness index, sediments transport index, ground roughness, basin area, bending coefficient, source material, and normalised difference vegetation index, have been selected for debris flow susceptibility evaluation. Analytical hierarchy process combined with Extension method has been used to calculate the susceptibility level of Datong and Taicun gullies. The evaluation result shows that both the gullies have a moderate susceptibility to debris flow. The result suggests that all the ongoing engineering projects such as mining and road construction work should be done with all precautionary measures, and the excavated material should adequately store in the gullies. Doi: 10.28991/cej-2021-03091702 Full Text: PD

Forecasting long-term sediment yield from the upper North Fork Toutle River, Mount St. Helens, USA

The Toutle-Cowlitz River system experienced dramatic landscape disturbance during the catastrophic eruption of Mount St Helens on May 18, 1980. The eruption was triggered by a 2.5 km3 debris avalanche which buried the upper 60 km2 of the North Fork Toutle River catchment to an average depth of 45 m and obliterated the surface drainage network. Subsequent channel response on the debris avalanche, dominated by incision and widening, has delivered significant quantities of sediment to downstream reaches where resultant deposition has reduced channel capacity and heightened flood risk. Estimates of future sediment yield from the upper North Fork Toutle River are therefore required to inform development of sustainable options for long-term flood risk mitigation. Previous estimates have been based on extrapolation of post-eruption trends in sediment yield and channel network evolution, but the divergent predictions reported in a number of studies have clouded effective decision-making regarding long-term sediment management. This study therefore uses a numerical, landscape evolution model (CAESAR-Lisflood) to make long-term forecasts of sediment yield based on process simulation rather than extrapolation. A suite of forecasts of cumulative catchment sediment yields up to 2100 are produced using scenario-based model runs designed to account for uncertainty associated with the hydrological impacts of climate change and the model coefficient for lateral mobility. The forecasts fall in a narrow band +/-20% of the mean that lies between two previous estimates derived from the extrapolation of post-eruption trends. Importantly, predicted trends in future annual sediment yield are predominantly linear, although some limited decay is evident for runs in which modelled channel lateral mobility is lower. Sustained sediment production in the upper North Fork Toutle River is found to result from persistent bank erosion and channel widening. These findings cast doubt on the applicability of negative exponential decay functions based on the rate law to characterise post-disturbance sediment yield when lateral rather than vertical adjustments dominate channel evolution. Moreover, forecast trends in future sediment yield suggest that it may not be possible to manage future sediment-related flood risk along the lower Cowlitz solely by retaining sediment in the upper North Fork Toutle River catchment

A hybrid computational intelligence approach to groundwater spring potential mapping

© 2019 by the authors. This study proposes a hybrid computational intelligence model that is a combination of alternating decision tree (ADTree) classifier and AdaBoost (AB) ensemble, namely "AB-ADTree", for groundwater spring potential mapping (GSPM) at the Chilgazi watershed in the Kurdistan province, Iran. Although ADTree and its ensembles have been widely used for environmental and ecological modeling, they have rarely been applied to GSPM. To that end, a groundwater spring inventory map and thirteen conditioning factors tested by the chi-square attribute evaluation (CSAE) technique were used to generate training and testing datasets for constructing and validating the proposed model. The performance of the proposed model was evaluated using statistical-index-based measures, such as positive predictive value (PPV), negative predictive value (NPV), sensitivity, specificity accuracy, root mean square error (RMSE), and the area under the receiver operating characteristic (ROC) curve (AUROC). The proposed hybrid model was also compared with five state-of-the-art benchmark soft computing models, including singleADTree, support vector machine (SVM), stochastic gradient descent (SGD), logistic model tree (LMT), logistic regression (LR), and random forest (RF). Results indicate that the proposed hybrid model significantly improved the predictive capability of the ADTree-based classifier (AUROC = 0.789). In addition, it was found that the hybrid model, AB-ADTree, (AUROC = 0.815), had the highest goodness-of-fit and prediction accuracy, followed by the LMT (AUROC = 0.803), RF (AUC = 0.803), SGD, and SVM (AUROC = 0.790) models. Indeed, this model is a powerful and robust technique for mapping of groundwater spring potential in the study area. Therefore, the proposed model is a promising tool to help planners, decision makers, managers, and governments in the management and planning of groundwater resources

Forecasting long-term sediment yield from the upper North Fork Toutle River, Mount St. Helens, USA

The Toutle-Cowlitz River system experienced dramatic landscape disturbance during the catastrophic eruption of Mount St Helens on May 18, 1980. The eruption was triggered by a 2.5 km3 debris avalanche which buried the upper 60 km2 of the North Fork Toutle River catchment to an average depth of 45 m and obliterated the surface drainage network. Subsequent channel response on the debris avalanche, dominated by incision and widening, has delivered significant quantities of sediment to downstream reaches where resultant deposition has reduced channel capacity and heightened flood risk. Estimates of future sediment yield from the upper North Fork Toutle River are therefore required to inform development of sustainable options for long-term flood risk mitigation. Previous estimates have been based on extrapolation of post-eruption trends in sediment yield and channel network evolution, but the divergent predictions reported in a number of studies have clouded effective decision-making regarding long-term sediment management. This study therefore uses a numerical, landscape evolution model (CAESAR-Lisflood) to make long-term forecasts of sediment yield based on process simulation rather than extrapolation. A suite of forecasts of cumulative catchment sediment yields up to 2100 are produced using scenario-based model runs designed to account for uncertainty associated with the hydrological impacts of climate change and the model coefficient for lateral mobility. The forecasts fall in a narrow band +/-20% of the mean that lies between two previous estimates derived from the extrapolation of post-eruption trends. Importantly, predicted trends in future annual sediment yield are predominantly linear, although some limited decay is evident for runs in which modelled channel lateral mobility is lower. Sustained sediment production in the upper North Fork Toutle River is found to result from persistent bank erosion and channel widening. These findings cast doubt on the applicability of negative exponential decay functions based on the rate law to characterise post-disturbance sediment yield when lateral rather than vertical adjustments dominate channel evolution. Moreover, forecast trends in future sediment yield suggest that it may not be possible to manage future sediment-related flood risk along the lower Cowlitz solely by retaining sediment in the upper North Fork Toutle River catchment

OPTIMIZING STOCHASTIC SUSCEPTIBILITY MODELLING FOR DEBRIS FLOW LANDSLIDES: MODEL EXPORTATION, STATISTICAL TECHNIQUES COMPARISON AND USE OF REMOTE SENSING DERIVED PREDICTORS. APPLICATIONS TO THE 2009 MESSINA EVENT.

Il presente lavoro di ricerca è stato sviluppato al fine di approfondire approcci metodologici nell'ambito della sucscettibilità da frana. In particolare, il tema centrale della ricerca è rappresentato dal tema specifico dell'esportazione spaziale di modelli di suscettibilità nell'area mediterranea. All'interno del topic specifico dell'esportazione di modelli predittivi spaziali sono state approfondite tematiche relative all'utilizzo di differenti algoritmi o di differenti sorgenti, derivate da DEM o da coperture satellitari.The present work has been developed in order to enhance current methodological approaches within the big picture of the landslide susceptibility. In particular, the central topic was the spatial exportation of landslide susceptibility models within the Mediterranean sector. Within the specific subject pertaining to the spatial exportation of predictive models, different algorithms as well as different data sources have been tested. Data sources experiments assessed the integration of DEM- and remotely sensed- derived parameters in order to improve the landslide prediction