Análise da vulnerabilidade a deslizamentos no espaço urbano de Manaus

Abstract

The global climate currently presents significant modifications in its cycles, with the intensification of occurrences of natural disasters such as landslides, floods and extreme droughts, among others. According to a survey by the National Center for Monitoring and Alerts of Natural Disasters (CEAMADEN), in Brazil, the occurrence of these phenomena, in 2023, reached the record of 1,161 cases, and in the ranking of affected municipalities, Manaus was in first place, with 23 occurrences. The city of Manaus is in a tropical region where the high incidence of precipitation is one of the relevant climatic factors in the environmental responses of the region. Thus, the main disaster events in the municipality are related to, flooding, flooding and landslides. Considering this local scenario, the study aimed to understand the dynamics of the phenomena of urban landslides based on the data of the records of the last 20 years, under the responsibility of the Municipal Civil Defense of Manaus, relating the occurrences to a set of socio-environmental characteristics aimed at generating an interpretation of the patterns of spatial variability of the dynamics of this type of natural disaster. To arrive at a spatial interpretation of the phenomenon of landslides, geoprocessing techniques were used. For this, the records of occurrences of landslides were related to a set of specialized variables formed by data with the level of the underground aquifer, the slope of the relief, the use and occupation of the urban space, the demographic mesh according to the Brazilian Institute of Geography and Statistics - IBGE, the pluviometry with data from the National Institute of Meteorology - INMET, the National Center for Monitoring and Warnings of Natural Disasters, and the Brazilian Geological Service - SBG. In addition to this information were also characterized the parameters of the urban soil of Manaus obtained by the Geological Service of Brazil which has information from the reports of resistance to penetration of the sampler (NSPT) of the soil survey companies. The information coming from point analyses, the data surfaces were generated with the resource of the kriging, in this way the coverage of information for the study area was obtained. The modeling was developed according to the hierarchical analysis AHP, which is a mathematical method related to the factors seen in a study and that sets up values of weights in the criteria for each parameter. The variables analyzed were weighted following this systematic to elaborate the spatialization of the zones of vulnerability in Manaus. The product of this investigation is a matrix of socioenvironmental vulnerability confirmed by occurrence records, maps holding the geolocation of the records and its correlation with precipitation and local characteristics. Thus, the model developed with the validation of the records provides through precipitation the characterization of the regions of vulnerabilities. Therefore, the set of this modeling in relation to precipitation provides probabilities of the risk and instructs the delimited zones of the city to guide the public bodies mechanisms of resilience to the impact of the phenomenon on society.