Tatiana Sussel Gonçalves Mendes

Landslides induced by subsurface water infiltration represent a growing hazard in rapidly urbanizing regions, particularly where infrastructure is deficient. Leakage from potable water distribution systems can trigger slope instabilities that often remain undetected by conventional rainfall-based early warning systems. This study employs electrical resistivity tomography and three-dimensional resistivity imaging to identify leakage pathways and assess subsurface moisture conditions in a high-risk sector of Recife municipality, Northeastern Brazil. High-resolution 2D and 3D multigrad array surveys were conducted and converted into volumetric soil moisture estimates using empirical relationships. The results reveal a major infiltration zone and several shallow, spatially distributed leaks, with saturation levels frequently exceeding 30–40%, particularly in low-resistance soil layers as corroborated by standard penetration test data. Three-dimensional isosurface visualizations of moisture distribution further delineate critical saturation volumes. These findings highlight the utility of resistivity-based geophysical methods for detecting non-meteorological landslide triggers and support their integration into proactive risk monitoring strategies in vulnerable urban environments.

Os Centros de Referência da Assistência Social (CRAS) são considerados a porta de entrada do Sistema Único de Assistência Social (SUAS) no oferecimento da proteção social básica às famílias em situação de vulnerabilidade. Dada a importância do oferecimento destes serviços no território, o presente artigo analisa a exposição dos CRAS a riscos de inundação e de deslizamento. A partir da integração entre o Índice de Desenvolvimento dos CRAS (IDCras) e a Base Territorial Estatística de Áreas de Risco (BATER) foram analisados 2.277 CRAS localizados em 806 municípios brasileiros. A metodologia considerou a distância dos equipamentos às áreas de BATER, bem como uma análise qualitativa dos eixos do IDCras, que atribui pontuação à estrutura física, aos recursos humanos e aos serviços e benefícios de cada CRAS. A área-piloto do estudo foi a Bacia Hidrográfica do Rio Paraíba do Sul, região historicamente afetada por desastres. Os resultados evidenciaram que 12% (n = 273) do total de unidades do CRAS (n = 2277) estão inseridas na BATER e outros 6% (n = 136) estão inseridas no intervalo de 0,1 a 50 metros da BATER. Do total populacional, aproximadamente 5,5 milhões, 9,8% (528.173 pessoas) estão inseridas em áreas BATER. Destas, 28,63% (151.260) moradores não têm acesso ao lançamento de esgoto na rede geral. A análise qualitativa do IDCras revelou que os equipamentos expostos apresentam deficiências estruturais, como número insuficiente de salas ou capacidade limitada diante do número de pessoas atendidas, ainda que com boa qualificação em recursos humanos e serviços oferecidos. Esta análise evidencia que as deficiências estruturais pré-existentes potencializarão os desafios no atendimento à população em situações de emergência. A metodologia desenvolvida demonstra potencialidades de articulação intersetorial para a produção de conhecimento sobre riscos de desastres, e de utilização das bases de dados do IDCras e da BATER na geração de conhecimento para subsidiar a preparação do SUAS e do sistema de proteção e defesa civil na gestão de risco de desastres no Brasil.

Data-driven models are increasingly used for flood and landslide susceptibility mapping in rapidly urbanizing regions, particularly in the Global South. In this context, land use and land cover (LULC) is routinely adopted as a conditioning factor, although its geomorphological meaning and temporal consistency with hazard inventories are seldom evaluated. Information Value (IV) models have been widely applied to landslide susceptibility, but their use for flood susceptibility in complex coastal cities remains limited. This study evaluates IV-based flood and landslide susceptibility in Vitória, Brazil, a predominantly insular city characterized by sharp geomorphological contrasts and high population density. Two LULC datasets with different levels of urban detail were tested as conditioning factors alongside topographic and hydrological variables. Eighteen models were constructed for each hazard and validated using Area Under the Curve (AUC) metrics and expert judgement. Morphological attributes were the most important predictors: slope alone achieved an AUC of 0.90 for landslides, whereas elevation reached 0.71 for floods. The inclusion of LULC increased AUC values to 0.94–0.95 for landslides and 0.85–0.89 for floods, but also introduced spatial and temporal biases associated with stationary and coarsely classified land cover. Our findings highlight the limitations of incorporating LULC as a conditioning factor without temporal harmonization with hazard inventories or adequate urban class disaggregation. We argue that, in complex urban settings, LULC is more appropriately interpreted as a proxy for exposure and vulnerability than as a dominant predisposing factor, and that its use in predictive models should be critically assessed to avoid misleading conclusions.

This work presents a methodological approach for developing a 3D Virtual Reality model of a landslide in the urban area of the municipality of Petrópolis, State of Rio de Janeiro, Brazil. The 3D virtual reality model was generated from data obtained by Unmanned Aerial Vehicle, 3D modeling, and data integration in an immersive and interactive geovisualization environment. Some images from before the event were used to reconstruct the buildings on the hillside, and 3D modeling was carried out using parametric rules. The generated model can be used in a virtual reality room (for a team experience) or with virtual reality glasses (for an individual experience). Although the Virtual Reality models do not replace fieldwork, they aid in understanding the landslide triggering process and analysing the impact caused and have the potential to be used in educational projects for disaster prevention and risk reduction.

Introduction. Landslides occur when slope stability is compromised by natural factors, such as intense rainfall, and human factors, such as irregular occupation. Climate variations have made extreme precipitation events more frequent and severe, increasing the social, economic, and environmental impacts of disasters. Objective. This study evaluates the effectiveness of the Automatic Rainfall Half-Life Cluster System (ARHCS) for monitoring landslides in Jaboatão dos Guararapes comparing its alerts to those issued by National Center for Monitoring and Early Warning of Natural Disasters (Centro Nacional de Monitoramento e Alertas de Desastres Naturais, Cemaden). Methodology. ARHCS uses the concept of rainfall half-life to estimate soil saturation potential and incorporates cluster analysis and data inversion to define alert thresholds. The comparison with Cemaden’s alerts was conducted for the year 2021. Results. The results indicated high compatibility between the systems, with ARHCS demonstrating greater accuracy in issuing alerts for “high” and “very high” risk levels, in addition to a low incidence of alerts without occurrences. Conclusion. These findings suggest that ARHCS can complement the existing alert system, especially in municipalities with limited monitoring infrastructure.

The study aims to estimate the environmental critical thresholds using statistical approaches to understand the landslide conditioning factors that can trigger landslides in the Continental Basaltic Provinces a landslide-prone area, using as reference the landslides that occurred in an extreme rainfall event. The study area is a region that was the scene of an extreme hydrological event in January 2017, with an accumulated volume of rain of 163.9 mm in 8 hours, causing a widespread event of shallow planar landslides with more than 400 scars detected. Hydrological, anthropic, geological, geomorphological, and topographical features of this region were analyzed considering landslides and non-landslides samples set, and their influence in the event was carried out using the Frequency Ratio method, followed by Pearson's Linear Correlation Coefficient and Linear Regression. The results showed that this process helped us to understand environmental critical thresholds based on classes of conditioning factors that have a greater influence on rainfall-triggered landslide occurrences and, consequently, higher predictive capacity in the landslide susceptibility models with the same geoenvironmental parameters which is a valuable insight for risk management.

The Paraíba do Sul River Basin is an important sediment deposit, and this fact, coupled with its strategic location, makes the Paraíba Valley an important source of non-metallic minerals. Although the legislation on mineral extraction is very detailed and restrictive, this factor does not fully guarantee compliance with these legal issues. The purpose of this study is therefore to carry out a spatial analysis of sand mining pits in the municipality of Caçapava, in the state of São Paulo, with regard to compliance with specific legislation. The proposed method consists of identifying and characterizing the mining areas that do not comply with the legal parameters using spatial analysis tools based on distance and intersection. The results show that there are areas that do not comply with the law because they do not meet the minimum distance from urbanized areas, are in environmental protection areas and floodplains. These facts, in addition to the well-known environmental impacts caused by mining activities, pose risks to water bodies and their surroundings. It is concluded that the proposed method is an important tool for constant monitoring of these areas and can help environmental inspection bodies make more restrictive and assertive decisions. Keywords: Sand Mining. Submerged Pit. Spatial Analysis. Environmental Impacts. RESUMO - A Bacia do Rio Paraíba do Sul é um importante depósito de sedimentos, e tal fato, somado a sua localização estratégica, transforma o Vale do Paraíba em uma importante fonte do mineral não-metálico. A região conta com normativos acerca da extração mineral bastante específicos e restritivos, o que leva os empreendimentos minerários a envidarem grandes esforços para o cumprimento das questões legais. Assim, o presente estudo tem como objetivo realizar uma análise espacial das cavas de mineração de areia no município de Caçapava, Estado de São Paulo, quanto às legislações ambientais. O método utilizado consistiu na identificação e caracterização das áreas de mineração quanto às questões legais utilizando ferramentas de análise espacial baseadas em distância e intersecção. Como resultados, pode-se verificar a presença de áreas com desconformidades no que se refere à distância mínima de áreas urbanizadas, incidência em áreas de proteção ambiental e zonas de várzea. Tais fatos, somados aos já conhecidos impactos ambientais causados pela atividade de mineração, agravam os riscos aos corpos d’água e sua vizinhança. Conclui-se que o método proposto é uma importante ferramenta para o monitoramento constante dessas áreas e que pode auxiliar órgãos ambientais fiscalizadores a tomadas de decisão mais assertivas. Palavras-chave: Mineração de Areia. Cava Submersa. Análise Espacial. Impacto Ambiental. ABSTRACT - The Paraíba do Sul River Basin is an important sediment deposit, and this fact, coupled with its strategic location, makes the Paraíba Valley an important source of aggregates. The region has very specific and restrictive regulations on mineral extraction, which leads mining companies to make great efforts to comply with legal issues. Thus, this study aims to carry out a spatial analysis of sand mining pits in the municipality of Caçapava, in the state of São Paulo, concerning environmental legislation. The method used consisted of identifying and characterizing the mining areas in terms of legal issues using spatial analysis tools based on distance and intersection. The results show the presence of areas with non-compliance in terms of minimum distance from urbanized areas, incidence in environmental protection areas and floodplain zones. These facts, added to the already known environmental impacts caused by mining activities, aggravate the risks to water bodies and their surroundings. It is concluded that the proposed method is an important tool for constant monitoring of these areas and can help environmental inspection bodies make more assertive decisions. Keywords: Sand Mining. Submerged Pit. Spatial Analysis. Environmental Impacts.

Designing ecological corridors studies are much more common than studies that evaluate the effectiveness and practicality of implementation. Thus, this study aimed to identify and discuss factors that can influence the implementation of ecological corridors designed from a multicriteria analysis. For this purpose, the ecological corridor implementation efforts of a Non-Governmental Organization (NGO) in an Atlantic Forest region were evaluated. The following information about the restoration projects was collected from the NGO database: georeferenced restoration polygons, restoration technique, project size, motivation, and land use tenure characteristics of the restoration site. Restoration polygons were spatially referenced to the planned corridor areas and classified according to land use and land cover, slope, distance to roads and occurrence in Permanent Preservation Areas. The NGO implemented 455.0 hectares of restoration, with only 10.7% within proposed corridors. NGO projects were concentrated on ecological restoration, which presents significant differences between ecological corridors. In practice, the implementation of restoration areas was primarily guided by the local characteristics of the landscape, project’s constraints and the will and interest of rural landowners in restoring their properties. This differs from its planning, in which social and economic aspects were not considered and only the environmental variables were taken into.