Examinando por Materia "Landslides"

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    Correlation of Morphometric Variables for Landslides in the Combeima River Basin, Colombia
    (Universidad EAFIT, 2020-06-19) Santa-Ramírez, Gabriel; Cuevas-González, Juan; Leal-Villamíl, Julián; Muñoz-Ramos, Jader; Universidad del Tolima
    This study was carried out in order to estimate the morphometric variables of the landslides found in Combeima river basin (Tolima, Colombia) and obtain possible statistical correlations. To obtain the morphometric characteristics of the landslides, we used a database with historical landslides, a RapidEye image from 2010 and an orthophotomosaic from 2009, where the landslides were visually identified. The morphometric characteristics were defined through a geographic information system and bivariate analyzes were ran between the morphometric variables to establish their correlations. The results allowed to identify 121 landslides, with an average area of 1,974.97 m2 and Birnbaum-Saunders type distribution. It was found that the slip area morphometric variable correlates with the total length (R2=0.9414), the length of the center line (R2=0.9368) and the width of the surface of rupture of this (R2=0.8915). These data could be used to infer the volume of the mass involved in the event and its potential effects . This result would allow the landslide area to be used as support in decision-making in the planning of the territory in the Combeima river basin.
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    Evaluación de la amenaza a movimientos en masa en función de la precipitación : un análisis con TRIGRS
    (Universidad EAFIT, 2025) Herazo Germán, Tulio Daniel; Ruiz Restrepo, Daniel
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    Evaluación de métodos heurísticos y estadísticos para zonificación de amenazas por movimientos en masa a escalas intermedias
    (Universidad EAFIT, 2021) Gamboa Ramírez, Marco Fidel; Bedoya Sanmiguel, Oscar Geovany
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    Influence of the ENSO on the spatial and temporal variability ocurrence of landslides triggered by rain in the Andean region
    (Universidad EAFIT, 2019-06-04) Naranjo Bedoya, Karolina; Aristizábal Giraldo, Edier Vicente; Morales Rodelo, José Alfred; Universidad Nacional de Colombia
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    Modeling the generation and propagation of rain-triggered landslides
    (Universidad EAFIT, 2025) Rodríguez Díaz, Andrés Camilo; Ruiz Restrepo, Daniel Felipe
    Slope stability is of great importance when the associated hazard implies a risk of human and economic losses. When a morphodynamic process materializes, there is a possibility that it may evolve into a debris and mudflow, especially when the mobilized mass is large and the phenomenon occurs in mountainous or steeply sloping terrain, where the soil mass may be channeled through watercourses or low-lying areas of the landform. Currently, the numerical modeling of such landslide phenomena is mainly performed using limit equilibrium or finite element methods. However, these approaches present major limitations when dealing with large deformations. For example, the finite element method is constrained when oscillations between tensile and compressive stresses are generated. In addition, the discretized elements must remain connected; otherwise, the analysis fails to converge. This research proposes to model the initiation and propagation of a rain-induced, large-deformation landslide. The modeling is structured in two stages: i) simulation of transient rainfall and infiltration using FEM (Finite Element Method), to generate conditions where convergence cannot be reached before failure; ii) export of the FEM results, mainly pore pressures and stress states for each element, to serve as initial conditions in an MPM (Material Point Method) environment, where the movement of the failed mass is modeled according to the characteristics defined for an idealized slope representing natural conditions. To achieve this objective, a review of the numerical and constitutive bases of the methods was carried out, together with a survey of previous research on the numerical modeling of large-deformation landslides using the two approaches mentioned above. Subsequently, the geometry of an idealized slope was defined to allow predictive modeling. For this purpose, rainfall data and terrain parameters were selected from existing information for the Greater Medellín area and the Aburrá Valley in Colombia. For the rainfall input, thresholds defined by the Early Warning System of Medellín and the Aburrá Valley (SIATA), a local hazard and risk monitoring agency, were used. A rainfall threshold can be defined, in simplified terms, as the boundary between rainfall events that can potentially trigger mass movements, usually combining data on antecedent and triggering rainfall (90-day and 7-day windows in the SIATA case). For this study, three particular threshold scenarios were selected, producing three different combinations of antecedent and triggering rainfall. Finally, conclusions are drawn regarding the adaptation of the two-stage modeling approach for this type of landslide. The methodology takes advantage of the computational efficiency of FEM for simulating the initiation of mass movement, and of MPM for modeling the subsequent propagation of the soil mass across the topography. The study highlights the potential benefits for risk management of using low-cost basic information (rainfall thresholds) as an alternative to traditional and more expensive monitoring instruments such as inclinometers and piezometers.
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    Prediction of landslide occurrence in urban areas located on volcanic ash soils in Pereira, Colombia
    (Springer Verlag, 2004-01-01) Rios, D.A.; Hermelin, M.; Universidad EAFIT. Departamento de Ciencias; Geología Ambiental y Tectónica
    As a result of the 25 January 1999 Armenia earthquake, the city of Pereira (400,000 inhabitants), located on a volcanic ash-covered alluvial fan in the western limit of the Central Cordillera (Colombia), suffered 250 slope movements. After a complete inventory, a monitoring process of unstable areas was designed, based on repeated topographic surveys, soil pore saturation levels and visual inspections. The participation of the communities was crucial and permitted the prediction of slope movements between 2 weeks and 3 months in advance and the evacuation of the inhabitants. Three specific examples are discussed. The method could be improved by excavating observation trenches and observing in detail local rainfall. In all cases, the strong involvement of the community was considered indispensable for the success of the process. © Springer-Verlag 2004.
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