This paper presents a practical application of the use of Information and Communication Technologies (ICT) in disaster risk management in urban regions. The objective is to propose, based on a case study: The Chiquihuite hill landslide, one of how the information from the Hydrological Observatory of the UNAM can be used to improve disaster management generated by extreme rainfall. In this case study, the OH-IIUNAM data are used for the temporal and spatial analysis of the storms that occurred in the Metropolitan Zone of the Valley of Mexico between September 1st and 9th, 2021, together with the earthquake that occurred on September 7, the conjunction of both phenomena produced a landslide of the hill on September 10th, 2021, which caused great damage to homes and human losses. The temporal analysis found that the most important storms occurred between September 1st and 8th, with the storms of days 6th and 7th standing out in terms of intensity and accumulated precipitation. As for the spatial analysis, IDW interpolation was used to estimate the precipitation in the entire Mexico City from September 1st to 9th. It was found that the Chiquihuite hill area was one where the greatest amount of precipitation. | En este trabajo se presenta una aplicación práctica del uso de las tecnologías de la información y comunicación (TIC) en la gestión de riesgos de desastres debidos a precipitaciones extremas en regiones urbanas. El objetivo es plantear, a partir del caso de estudio del deslizamiento del cerro del Chiquihuite, una de las formas en las que se puede aprovechar la información del Observatorio Hidrológico del Instituto de Ingeniería de la Universidad Nacional Autónoma de México (OH-IIUNAM) para mejorar la gestión de desastres generadas por precipitaciones extremas. En el caso de estudio, se utilizan los datos del OH-IIUNAM para el análisis temporal y espacial de las tormentas que se presentaron en la Zona Metropolitana del Valle de México entre el 1 y 9 de septiembre de 2021; también se considera el sismo que ocurrió el 7 de septiembre del mismo año. La conjunción de ambos fenómenos produjo un deslizamiento del cerro el 10 de septiembre de 2021, que provocó grandes daños en las viviendas y pérdidas humanas. En el análisis temporal realizado se encontró que las tormentas más importantes ocurrieron entre los días 1 y 8 de septiembre, destacando las tormentas de los días 6 y 7 en intensidad y precipitación acumulada. En cuanto al análisis espacial, se utilizó la interpolación IDW (interpolación de distancia inversa ponderada) para estimar la precipitación en toda la Ciudad de México (CDMX) en el periodo del 1 al 9 de septiembre, encontrándose que la zona del cerro del Chiquihuite fue una de las áreas donde cayó mayor cantidad de agua de lluvia.

Fissures and paleosols are important factors affecting the slope stability of loess. However, the mechanism of water and air migration in the unsaturated zone of loess induced by fissures and paleosols remains unclear. In this study, discontinuous irrigation experiments were conducted using a sand tank and Marriott bottle. The soil- water content (SWC) patterns and pressure differences, under the influence of fissures and paleosols, were observed using the EC-5 moisture sensor and MPXV5010DP differential pressure sensor. The results showed that the fissures are the dominant channels of water infiltration and air exchange, while paleosols and closed soil boundary conditions can significantly impede the downward transport of water and air. During irrigation, SWC near the fissure and paleosol increased rapidly from less than 10–30%, reaching a maximum value of 35% above the paleosol. On the other hand, the maximum pressure difference in the upper part of the paleosol exceeded 1,000 Pa, which is significantly higher than that observed in the lower part. The stability of soil around fissures and paleosols decreased sharply due to high SWC and pressure differences, which may induce landslides after long-term irrigation. This study provides a theoretical basis for revealing the formation mechanism of landslides in loess irrigation areas and preventing landslide disasters.

The analysis of pre-existing landslides and landslide-prone hillslopes requires an estimation of maximum groundwater levels. Rapid increase in groundwater levels may be a dominant factor for evaluating the occurrence of landslides. System identification—use of mathematical tools and algorithms for building dynamic models from measured data—is adopted in this study. The fluid mass-balance equation is used to model groundwater-level fluctuations, and the model is analytically solved using the finite-difference method. Entropy-based classification (EBC) is used as a data-mining technique to identify the appropriate ranges of influencing variables. The landslide area at Wushe Reservoir, Nantou County, Taiwan, is chosen as a field test site for verification. The study generated 65,535 sets of numbers for the groundwater-level variables of the governing equation, which is judged by root mean square errors. By applying cross-validation methods and EBC, limited numbers of validation samples are used to find the range of each parameter. For these ranges, a heuristic method is employed to find the best results of each parameter for the prediction model of groundwater level. The ranges for governing factors are evaluated and the resulting performance is examined.

Groundwater-level rise plays an important role in the activation or reactivation of deep-seated landslides and so hydromechanical studies require a good knowledge of groundwater flows. Anisotropic and heterogeneous media combined with landslide deformation make classical hydrogeological investigations difficult. Hydrogeological investigations have recently focused on indirect hydrochemistry methods. This study aims at determining the groundwater conceptual model of the Séchilienne landslide and its hosting massif in the western Alps (France). The hydrogeological investigation is streamlined by combining three approaches: a one-time multi-tracer test survey during high-flow periods, a seasonal monitoring of the water stable-isotope content and electrical conductivity, and a hydrochemical survey during low-flow periods. The complexity of the hydrogeological setting of the Séchilienne massif leads to development of an original method to estimate the elevations of the spring recharge areas, based on topographical analyses and water stable-isotope contents of springs and precipitation. This study shows that the massif supporting the Séchilienne landslide is characterized by a dual-permeability behaviour typical of fractured-rock aquifers where conductive fractures play a major role in the drainage. There is a permeability contrast between the unstable zone and the intact rock mass supporting the landslide. This contrast leads to the definition of a shallow perched aquifer in the unstable zone and a deep aquifer in the intact massif hosting the landslide. The perched aquifer in the landslide is temporary, mainly discontinuous, and its extent and connectivity fluctuate according to the seasonal recharge.