Mapeamento de áreas susceptíveis a escorregamentos no município de Caraguatatuba (SP) usando técnicas de sensoriamento remoto e SIG / Landslide susceptibility mapping in Caraguatatuba (SP) municipality using remote sensing and gis techniques

AUTOR(ES)
FONTE

IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia

DATA DE PUBLICAÇÃO

23/09/2003

RESUMO

The objective of the present research was the development of a quantitative approach for landslide susceptibility mapping using remote sensing and GIS techniques. In order to determine the best products for identifying landslide scars, six imagery fusion techniques (Brovey, HSV, PCA, IHS and two Wavelets) were evaluated and many geographical inference approaches were applied to obtain the landslide susceptibility map. The study area was Caraguatatuba municipality, São Paulo, Brazil, due to relatively recent catastrophic events of landslide that occurred there. ETM+ Landsat 7 (multispectral and PAN) and HRV Spot 4 (PAN) data were used for obtaining maps in the 1:100,000 scale. IHS fusion was the technique that better preserved the spatial/spectral quality and the photointerpretative potential from the studied imagery and thus it was used for identifying landslide scars of the study area. By Maxver classification and visual analysis a total of 497 landslide scars were mapped. From this total, 397 scars were utilized for ponder the environmental variables and thematic classes considered; the remaining 100 scars were kept apart for the validation phase of the obtained susceptibility maps. Boolean, Index Overlay, AHP and Conditional Probability were the used techniques of geographical inference. Boolean technique provided the worst result due the excessive generalization of the favorable areas of landsliding. Index Overlay and AHP provided intermediate similar results, mainly for the class Very High susceptibility of landslides (r2 = 62%). Conditional Probability was the better approach, providing a correlation of 95% for the Very High susceptibility class. Because their high slopes and shallow soils (Inceptisols), Serra-do-Mar medium hillsides were the more susceptible areas for the occurrence of landslides events.

ASSUNTO(S)

sensoriamento remoto escorregamentos fusão de dados mapeamento temático sensoriamento remoto sistemas de informações geográfica brasil caraguatatuba (sp) remote sensing sliding multisensor fusion thematic mapping remote sensing brazil caraguatatuba (town) geographic information systems

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