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Every year, Brazil grapples with the destructive impact of landslides, typically during the summer season. The National Centre for Monitoring and Alerts of Natural Disasters (Cemaden) places significant emphasis on studying these phenomena to understand their processes and causes more deeply. One key challenge faced in this endeavour is the procurement of geotechnical properties of the soil in high-risk areas, with soil moisture being a crucial factor. Collecting point samples for acquiring these geotechnical parameters is not only costly but also limited in providing a comprehensive two-dimensional or three-dimensional coverage. Therefore, the primary aim of the proposed project is to validate the method of acquiring soil moisture data through geophysical surveys in both 2D and 3D scenarios. Data was gathered from soil moisture stations within Cemaden's network and various collected samples to confirm the results. To generate more controlled yet realistic conditions, a sequence of field infiltration experiments was conducted. The findings, related to the ability of the geoelectric method to define soil moisture, derived from this project form an invaluable foundation for future investigations spearheaded by the Geodynamics Group and its collaborating institutions. • This paper presents a series of experiments to understand the method of acquiring soil moisture through the DC method. [ABSTRACT FROM AUTHOR]

Climate change has increased the frequency of extreme weather events and, consequently, the number of occurrences of natural disasters. In Brazil, among these disasters, floods, flash floods, and landslides account for the highest number of deaths, the latter being the most lethal. Bearing in mind the importance of monitoring areas susceptible to disasters, the REMADEN/REDEGEO project of the National Center for Monitoring and Natural Disaster Alerts (Cemaden) has promoted the installation of a network of soil moisture sensors in regions with a long history of landslides. This network was used in the present paper as a base to develop a system for moisture forecasting in those critical zones. The time series of rainfall and moisture were used in an inversion algorithm to obtain the geotechnical parameters of the soil. Then the geotechnical model was used in a forward calculation with the rainfall prediction to obtain the soil moisture forecast. The landslide events of March 2020 and May 2022 in Guarujá and Recife, respectively, were used as study cases for the developed system. The obtained results indicate that the proposed methodology has the potential to be used as an important tool in the decision-making process for issuing landslide alerts. • This paper presents a novel system aimed at predicting soil moisture conditions based on rainfall forecast data. [ABSTRACT FROM AUTHOR]

Abstract Every year, especially in summer, Brazil suffers from floods and landslides triggered by intense rainfall. These landslides are responsible for many fatalities and material losses that greatly affect the local population. The municipality of Campos do Jordão, in São Paulo state, presents such a history of mass movements that have resulted in fatalities and financial losses. A map of the municipality's risk assessment shows that about 32% of the municipality's population lives in risky areas. For this reason, Campos do Jordão is currently one of the pilot areas being used in studies for understanding landslides and mitigation techniques. In this context, this paper presents the results of an integration of geophysical surveys of, and geotechnical information on, the area. The geophysical methods applied were electrical resistivity, induced polarization, and frequency-domain electromagnetics. The geotechnical data included standard penetration test soundings and soil characterization (using particle density and X-ray fluorescence methods). The main contribution of this work is to present results from the joint application of these methodologies. Results from one of the critical areas, where a school had suffered the impact of a mass movement, indicated the displacement and burial of the retaining wall, which was built in 2002, as well as the shape of the movement, which affected the foundations of the school. It was also possible to determine the critical geological structures involved in the slope dislocation, and the potential problems with the school's foundations. The combined application of geophysical and geotechnical methods to landslide research is not very common, and so this study aimed to provide a field-based example to demonstrate the potential utility of such an integrated approach. The aim was also to foster collaboration with studies of mass movements in Brazil and help create methodologies for investigating and understanding the phenomenon. Highlights • Association of the mechanical resistance with the obtained geoelectrical layers • Determination of the current location of the buried retaining wall built in 2002 • Determination of the displacement of 8 m of the wall and shape of this displacement • FDEM and Soil Characterization defined two different soils types in the school yard. [ABSTRACT FROM AUTHOR]