Mapa de suscetibilidade a deslizamentos da regiÃo metropolitana de Recife

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The use of Remote Sensing and Geographical Information Systems (SIG) tools constitute alternative technologies of decreasing cost along the last decade, allowing planners of all government spheres in the process of more appropriate and efficiently planning the use of the soil and of the environment protection. The evaluation and the spatialization of the natural susceptibility to mass movements (sliding) are important tools in the measurement, giving to the public manager a new kowledge regarding possible problems in areas heavily occupied, or in the occupation phase. The Metropolitan Area of Recife (RMR), northeast Brazil, for many years lives together with the hills and slopes collapsing issues, where a high portion of the population lives, the majority consisting of low income people. These collapses caused dozens of deads and wounded persons along the 1980 and 1990 decades. It is important that the government agencies should effectively use these tools to properly locate the areas susceptible to collapsing, facilitating the administration. The methodology here proposed aims to reduce the costs of the elaboration of susceptibility maps, using geoprocessing tools and such remote sensing tools as SRTM radar images (Shutlle Radar Topographic Mission), Landsat satellite images, Geocover and CBERS, and other information available via Internet. Regarding SRTM images, they can extract relatively important information concerning planimetry, orientation of hillsides and horizontal and vertical profiles, satellite images concerning the use of the soil and geomorphology. Such information, inserted in SIGâs (Geographical Information Systems), allow the reclassification and updating of these parameters. They allow those operations to be repeated several times, in the search of the adjustment to the wanted model. These data were obtained after the processing of the data of SUDENE topographical sheets (Superintendency of Development of the Northeast) and of SRTM, the maps of hillsides (horizontal and vertical) profiles, and also the level curves that made it possible to generate the topographical map of the area. Using the method of the algebra of maps (overlap of several themes), it was possible to generate the susceptibility map to sliding, quite reliable, when compared with the mapping of existent risky areas. The newly obtained map, when compared with the one produced by Alheiros (1998), got 71,72% of similarity among the areas of susceptibility classes. Though, when compared with the risk map elaborated for the municipal district of Recife, the value arrives to 79, 42%. The values among the several susceptibility classes in RMR show, respectively, that 49,68% of the RMR area present low susceptibility to the sliding events, 47,80% average susceptibility and 2,51% high susceptibility to the sliding, with variations depending on the used topographical data (if it was extracted from the SUDENE topographical sheets or of the SRTM radar)

ASSUNTO(S)

suscetibilidade movimentos de massa riscos geolÃgicos geoprocessamento regiÃo metropolitana do recife geographical information systems deslizamentos susceptibility geociencias metropolitan area of recife geoprocessing

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