Novel Approaches in Landslide Monitoring and Data Analysis

Significant progress has been made in the last few years that has expanded the knowledge of landslide processes. It is, therefore, necessary to summarize, share and disseminate the latest knowledge and expertise. This Special Issue brings together novel research focused on landslide monitoring, modelling and data analysis

Recommendations for the quantitative analysis of landslide risk

This paper presents recommended methodologies for the quantitative analysis of landslide hazard, vulnerability and risk at different spatial scales (site-specific, local, regional and national), as well as for the verification and validation of the results. The methodologies described focus on the evaluation of the probabilities of occurrence of different landslide types with certain characteristics. Methods used to determine the spatial distribution of landslide intensity, the characterisation of the elements at risk, the assessment of the potential degree of damage and the quantification of the vulnerability of the elements at risk, and those used to perform the quantitative risk analysis are also described. The paper is intended for use by scientists and practising engineers, geologists and other landslide experts.JRC.H.5-Land Resources Managemen

Landslide susceptibility maps of Italy: lesson learnt from dealing with multiple landslide classes and the uneven spatial distribution of the national inventory

Landslide susceptibility corresponds to the probability of landslide occurrence across a given geographic space. This probability is usually estimated by using a binary classifier which is informed of landslide presence/absence data and associated landscape characteristics. Here, we consider the Italian national landslide inventory to repare slope-unit based landslide susceptibility maps. These maps are prepared for the eight types of mass movements existing in the inventory, (Complex, Deep Seated Gravitational Slope Deformation, Diffused Fall, Fall, Rapid Flow, Shallow, Slow Flow, Translational) and build one susceptibility map for each type. The analysis – carried out by using a Bayeian version of a Generalized Additive Model with a multiple intercept for each Italian region – revealed that the inventory may have been compiled with different levels of detail. This would be consistent with the datases being assembled from twenty sub– inventories, each prepared by different administrations of the Italian regions. As a result, this spatial inhonomegenity may lead to a biased national–scale susceptibility maps. On the basis of these considerations, we further analyzed the national database to confirm or reject the varying quality hypothesis suggested by the multiple intercepts results. For each landslide type, we then tried to build unbiased susceptibility models by removing regions with a poor landslide inventory from the calibration stage, and used them only as a prediction target of a simulation routine. We analyzed the resulting eight maps finding out a congruent dominant pattern in the Alpine and Apennine sectors. The whole procedure is implemented in R–INLA. This allowed to examine fixed(linear) and random (nonlinear) effects from an interpretative standpoint and produced a full prediction equipped with an estimated uncertainty. We propose this overall modeling pipeline for any landslide datasets where a significant mapping bias may influence the susceptibility pattern over space.<br/

Spatial prediction of landslide susceptibility/intensity through advanced statistical approaches implementation: applications to the Cinque Terre (Eastern Liguria, Italy)

Landslides are frequently responsible for considerable huge economic losses and casualties in mountainous regions especially nowadays as development expands into unstable hillslope areas under the pressures of increasing population size and urbanization (Di Martire et al. 2012). People are not the only vulnerable targets of landslides. Indeed, mass movements can easily lay waste to everything in their path, threatening human properties, infrastructures and natural environments. Italy is severely affected by landslide phenomena and it is one of the most European countries affected by this kind of phenomena. In this framework, Italy is particularly concerned with forecasting landslide effects (Calcaterra et al. 2003b), in compliance with the National Law n. 267/98, enforced after the devastating landslide event of Sarno (Campania, Southern Italy). According to the latest Superior Institute for the Environmental Protection and Research (ISPRA, 2018) report on "hydrogeological instability" of 2018, it emerges that the population exposed to landslides risk is more than 5 million and in particular almost half-million falls into very high hazard zones. The slope stability can be compromised by both natural and human-caused changes in the environment. The main reasons can be summarised into heavy rainfalls, earthquakes, rapid snow-melts, slope cut due to erosions, and variation in groundwater levels for the natural cases whilst slopes steepening through construction, quarrying, building of houses, and farming along the foot of mountainous zone correspond to the human component. This Ph.D. thesis was carried out in the Liguria region, inside the Cinque Terre National Park. This area was chosen due to its abundance of different types of landslides and its geological, geomorphological and urban characteristics. The Cinque Terre area can be considered as one of the most representative examples of human-modified landscape. Starting from the early centuries of the Middle Ages, local farmers have almost completely modified the original slope topography through the construction of dry-stone walls, creating an outstanding terraced coastal landscape (Terranova 1984, 1989; Terranova et al. 2006; Brandolini 2017). This territory is extremely dynamic since it is characterized by a complex geological and geomorphological setting, where many surficial geomorphic processes coexist, along with peculiar weather conditions (Cevasco et al. 2015). For this reason, part of this research focused on analyzing the disaster that hit the Cinque Terre on October, 25th, 2011. Multiple landslides took place in this occasion, triggering almost simultaneously hundreds of shallow landslides in the time-lapse of 5-6 hours, causing 13 victims, and severe structural and economic damage (Cevasco et al. 2012; D\u2019Amato Avanzi et al. 2013). Moreover, this artificial landscape experienced important land-use changes over the last century (Cevasco et al. 2014; Brandolini 2017), mostly related to the abandonment of agricultural activity. It is known that terraced landscapes, when no longer properly maintained, become more prone to erosion processes and mass movements (Lesschen et al. 2008; Brandolini et al. 2018a; Moreno-de-las-Heras et al. 2019; Seeger et al. 2019). Within the context of slope instability, the international community has been focusing for the last decade on recognising the landslide susceptibility/hazard of a given area of interest. Landslide susceptibility predicts "where" landslides are likely to occur, whereas, landslide hazard evaluates future spatial and temporal mass movement occurrence (Guzzetti et al., 1999). Although both definitions are incorrectly used as interchangeable. Such a recognition phase becomes crucial for land use planning activities aimed at the protection of people and infrastructures. In fact, only with proper risk assessment governments, regional institutions, and municipalities can prepare the appropriate countermeasures at different scales. Thus, landslide susceptibility is the keystone of a long chain of procedures that are actively implemented to manage landslide risk at all levels, especially in vulnerable areas such as Liguria. The methods implemented in this dissertation have the overall objective of evaluating advanced algorithms for modeling landslide susceptibility. The thesis has been structured in six chapters. The first chapter introduces and motivates the work conducted in the three years of the project by including information about the research objectives. The second chapter gives the basic concepts related to landslides, definition, classification and causes, landslide inventory, along with the derived products: susceptibility, hazard and risk zoning, with particular attention to the evaluation of landslide susceptibility. The objective of the third chapter is to define the different methodologies, algorithms and procedures applied during the research activity. The fourth chapter deals with the geographical, geological and geomorphological features of the study area. The fifth chapter provides information about the results of the applied methodologies to the study area: Machine Learning algorithms, runout method and Bayesian approach. Furthermore, critical discussions on the outcomes obtained are also described. The sixth chapter deals with the discussions and the conclusions of this research, critically analysing the role of such work in the general panorama of the scientific community and illustrating the possible future perspectives

On the use of explainable AI for susceptibility modeling: Examining the spatial pattern of SHAP values

Hydro-morphological processes (HMP, any natural phenomenon contained within the spectrum defined between debris flows and flash floods) are globally occurring natural hazards which pose great threats to our society, leading to fatalities and economical losses. For this reason, understanding the dynamics behind HMPs is needed to aid in hazard and risk assessment. In this work, we take advantage of an explainable deep learning model to extract global and local interpretations of the HMP occurrences across the whole Chinese territory. We use a deep neural network architecture and interpret the model results through the spatial pattern of SHAP values. In doing so, we can understand the model prediction on a hierarchical basis, looking at how the predictor set controls the overall susceptibility as well as doing the same at the level of the single mapping unit. Our model accurately predicts HMP occurrences with AUC values measured in a ten-fold cross-validation ranging between 0.83 and 0.86. This level of predictive performance attests for an excellent prediction skill. The main difference with respect to traditional statistical tools is that the latter usually lead to a clear interpretation at the expense of high performance, which is otherwise reached via machine/deep learning solutions, though at the expense of interpretation. The recent development of explainable AI is the key to combine both strengths. In this work, we explore this combination in the context of HMP susceptibility modeling. Specifically, we demonstrate the extent to which one can enter a new level of data-driven interpretation, supporting the decision-making process behind disaster risk mitigation and prevention actions

Rockfall Source Identification Using a Hybrid Gaussian Mixture-Ensemble Machine Learning Model and LiDAR Data

The availability of high-resolution laser scanning data and advanced machine learning algorithms has enabled an accurate potential rockfall source identification. However, the presence of other mass movements, such as landslides within the same region of interest, poses additional challenges to this task. Thus, this research presents a method based on an integration of Gaussian mixture model (GMM) and ensemble artificial neural network (bagging ANN [BANN]) for automatic detection of potential rockfall sources at Kinta Valley area, Malaysia. The GMM was utilised to determine slope angle thresholds of various geomorphological units. Different algorithms(ANN, support vector machine [SVM] and k nearest neighbour [kNN]) were individually tested with various ensemble models (bagging, voting and boosting). Grid search method was adopted to optimise the hyperparameters of the investigated base models. The proposed model achieves excellent results with success and prediction accuracies at 95% and 94%, respectively. In addition, this technique has achieved excellent accuracies (ROC = 95%) over other methods used. Moreover, the proposed model has achieved the optimal prediction accuracies (92%) on the basis of testing data, thereby indicating that the model can be generalised and replicated in different regions, and the proposed method can be applied to various landslide studies

PROBABILISTIC RISK MAPPING COUPLING BAYESIAN NETWORKS AND GIS, AND BAYESIAN MODEL CALIBRATION OF SUBMARINE LANDSLIDES.

A spatial and causal probabilistic methodology is introduced for risk assessment based on the coupling of a conceptual Bayesian Network (BN) model and GIS to generate risk maps. The proposed integration of these spatial events is referred to as BN+GIS, which features forward and inverse modeling, denoted in this work as spatial prognosis and spatial diagnosis, respectively. This approach is illustrated through two case studies: (1) environmental risk associated to oil and gas site developments implemented in the Barnett Shale Play in Texas, and (2) landslide susceptibility in the Elliott State Forest in the Oregon Coastal Range. This approach will equip stakeholders, such as land owners, operators, regulators, government officials, and other related organizations with a platform that can help them improve the assessment of future potential risk scenarios, and to identify likely consequences that would lead to undesirable states of environmental risks ahead of time. A sensitivity analysis was performed on BN+GIS to study the influence of some of the user-defined parameters on the model’s results, such as sample size, spatial interval of the systematic sampling methodology, and the prescribed diagnosis distribution used for decision making purposes. As an additional effort to portray the potential application of the Bayesian paradigm on risk assessment, a parameter estimation methodology is implemented using bathymetry data and CPT logs. This approach is illustrated through a study case, where information was mined from existent landslides to perform a Bayesian calibration on an infinite slope model. This approach allowed to estimate posterior probability distributions of physical parameters given a prescribed factor of safety, to assess the most likely depth of failure, and to identify the optimum amount of samples required to maximize the reliability of the inferences. This work focusses on providing a substantial contribution to improved policymaking and management through the use of integrated sources of evidence such as real data, model predictions and experts educated beliefs

Landslides

Landslides - Investigation and Monitoring offers a comprehensive overview of recent developments in the field of mass movements and landslide hazards. Chapter authors use in situ measurements, modeling, and remotely sensed data and methods to study landslides. This book provides a thorough overview of the latest efforts by international researchers on landslides and opens new possible research directions for further novel developments

Impact of DEM-derived factors and analytical hierarchy process on landslide susceptibility mapping in the region of Rożnów Lake, Poland

El artículo analiza las desigualdades que se gestan y reproducen en las trayectorias educativas universitarias de los jóvenes ecuatorianos en España y Ecuador en el contexto de la crisis, centrándose en las estrategias vinculadas a la movilidad de estos jóvenes y sus familias y el papel que juegan las políticas públicas. Se examinan los recorridos de tres grupos de universitarios: las hijas e hijos de la migración de los 2000, los retornados a Ecuador y los que llegan a España gracias a las ayudas del gobierno ecuatoriano para realizar postgrados. Se parte de una metodología fundamentalmente cualitativa basada en entrevistas, grupos de discusión y una encuesta a los participantes desde España de la prueba de acceso para integrarse en universidades públicas ecuatorianas. Los hallazgos ponen de relieve los capitales que manejan unos y otros y las restricciones sociales y económicas que encuentran. Mientras el primer grupo intenta mantenerse en la universidad, aun degradando sus expectativas, en el segundo grupo se advierte que la educación forma parte de en una estrategia más amplia que descansa en las redes transnacionales tejidas durante más de una década de migración hacia España. Finalmente, los del tercero han seguido trayectorias heterogéneas ascendentes que incluyen el desplazamiento.El artículo analiza las desigualdades que se gestan y reproducen en las trayectorias educativas universitarias de los jóvenes ecuatorianos en España y Ecuador en el contexto de la crisis, centrándose en las estrategias vinculadas a la movilidad de estos jóvenes y sus familias y el papel que juegan las políticas públicas. Se examinan los recorridos de tres grupos de universitarios: las hijas e hijos de la migración de los 2000, los retornados a Ecuador y los que llegan a España gracias a las ayudas del gobierno ecuatoriano para realizar postgrados. Se parte de una metodología fundamentalmente cualitativa basada en entrevistas, grupos de discusión y una encuesta a los participantes desde España de la prueba de acceso para integrarse en universidades públicas ecuatorianas. Los hallazgos ponen de relieve los capitales que manejan unos y otros y las restricciones sociales y económicas que encuentran. Mientras el primer grupo intenta mantenerse en la universidad, aun degradando sus expectativas, en el segundo grupo se advierte que la educación forma parte de en una estrategia más amplia que descansa en las redes transnacionales tejidas durante más de una década de migración hacia España. Finalmente, los del tercero han seguido trayectorias heterogéneas ascendentes que incluyen el desplazamiento.El artículo analiza las desigualdades que se gestan y reproducen en las trayectorias educativas universitarias de los jóvenes ecuatorianos en España y Ecuador en el contexto de la crisis, centrándose en las estrategias vinculadas a la movilidad de estos jóvenes y sus familias y el papel que juegan las políticas públicas. Se examinan los recorridos de tres grupos de universitarios: las hijas e hijos de la migración de los 2000, los retornados a Ecuador y los que llegan a España gracias a las ayudas del gobierno ecuatoriano para realizar postgrados. Se parte de una metodología fundamentalmente cualitativa basada en entrevistas, grupos de discusión y una encuesta a los participantes desde España de la prueba de acceso para integrarse en universidades públicas ecuatorianas. Los hallazgos ponen de relieve los capitales que manejan unos y otros y las restricciones sociales y económicas que encuentran. Mientras el primer grupo intenta mantenerse en la universidad, aun degradando sus expectativas, en el segundo grupo se advierte que la educación forma parte de en una estrategia más amplia que descansa en las redes transnacionales tejidas durante más de una década de migración hacia España. Finalmente, los del tercero han seguido trayectorias heterogéneas ascendentes que incluyen el desplazamiento.El artículo analiza las desigualdades que se gestan y reproducen en las trayectorias educativas universitarias de los jóvenes ecuatorianos en España y Ecuador en el contexto de la crisis, centrándose en las estrategias vinculadas a la movilidad de estos jóvenes y sus familias y el papel que juegan las políticas públicas. Se examinan los recorridos de tres grupos de universitarios: las hijas e hijos de la migración de los 2000, los retornados a Ecuador y los que llegan a España gracias a las ayudas del gobierno ecuatoriano para realizar postgrados. Se parte de una metodología fundamentalmente cualitativa basada en entrevistas, grupos de discusión y una encuesta a los participantes desde España de la prueba de acceso para integrarse en universidades públicas ecuatorianas. Los hallazgos ponen de relieve los capitales que manejan unos y otros y las restricciones sociales y económicas que encuentran. Mientras el primer grupo intenta mantenerse en la universidad, aun degradando sus expectativas, en el segundo grupo se advierte que la educación forma parte de en una estrategia más amplia que descansa en las redes transnacionales tejidas durante más de una década de migración hacia España. Finalmente, los del tercero han seguido trayectorias heterogéneas ascendentes que incluyen el desplazamiento.El artículo analiza las desigualdades que se gestan y reproducen en las trayectorias educativas universitarias de los jóvenes ecuatorianos en España y Ecuador en el contexto de la crisis, centrándose en las estrategias vinculadas a la movilidad de estos jóvenes y sus familias y el papel que juegan las políticas públicas. Se examinan los recorridos de tres grupos de universitarios: las hijas e hijos de la migración de los 2000, los retornados a Ecuador y los que llegan a España gracias a las ayudas del gobierno ecuatoriano para realizar postgrados. Se parte de una metodología fundamentalmente cualitativa basada en entrevistas, grupos de discusión y una encuesta a los participantes desde España de la prueba de acceso para integrarse en universidades públicas ecuatorianas. Los hallazgos ponen de relieve los capitales que manejan unos y otros y las restricciones sociales y económicas que encuentran. Mientras el primer grupo intenta mantenerse en la universidad, aun degradando sus expectativas, en el segundo grupo se advierte que la educación forma parte de en una estrategia más amplia que descansa en las redes transnacionales tejidas durante más de una década de migración hacia España. Finalmente, los del tercero han seguido trayectorias heterogéneas ascendentes que incluyen el desplazamiento.El artículo analiza las desigualdades que se gestan y reproducen en las trayectorias educativas universitarias de los jóvenes ecuatorianos en España y Ecuador en el contexto de la crisis, centrándose en las estrategias vinculadas a la movilidad de estos jóvenes y sus familias y el papel que juegan las políticas públicas. Se examinan los recorridos de tres grupos de universitarios: las hijas e hijos de la migración de los 2000, los retornados a Ecuador y los que llegan a España gracias a las ayudas del gobierno ecuatoriano para realizar postgrados. Se parte de una metodología fundamentalmente cualitativa basada en entrevistas, grupos de discusión y una encuesta a los participantes desde España de la prueba de acceso para integrarse en universidades públicas ecuatorianas. Los hallazgos ponen de relieve los capitales que manejan unos y otros y las restricciones sociales y económicas que encuentran. Mientras el primer grupo intenta mantenerse en la universidad, aun degradando sus expectativas, en el segundo grupo se advierte que la educación forma parte de en una estrategia más amplia que descansa en las redes transnacionales tejidas durante más de una década de migración hacia España. Finalmente, los del tercero han seguido trayectorias heterogéneas ascendentes que incluyen el desplazamiento.In the paper we analyze the inequalities that emerge from and are reproduced in Ecuadorian's higher education trajectories in the context of economic crises. We focus on the strategies that these youth and their families employ for social mobility as well as the role of public policy in these processes. We examine the trajectories of three groups: sons and daughters of the 2000 migration wave from Ecuador to Spain who study at universities in Spain, those who have returned to Ecuador for their studies, and Ecuadorians who move to Spain in order to carry out postgraduate studies, some of them funded by scholarships from the Ecuadorian government. The research project employed a qualitative methodology based on interviews, focus groups and a survey with Ecuadorians in Spain who took the entrance exam for admittance into Ecuador's public university system. Our findings highlight the varied forms of capitals that these diverse students employ, as well as the social and economic constraints that they encounter. In a period of economic crisis in Spain, the first group of students must often downgrade their expectations in order to continue their studies. Their experience contrasts starkly with Ecuadorians undertaking postgraduate studies in Spain, whose heterogenous trajectories are upwardly and geographically mobile. The case of the return university students to Ecuador shows us that education is inserted into a broader strategy that depends on transnational networks shaped over more than a decade of Ecuador-Spain migration