APLICACIÓN DE MODELOS DIGITALES DE ELEVACIÓN BASADOS EN IMÁGENES SAR EN EL ESTUDIO DE LA GEOLOGÍA ESTRUCTURAL

PABLO EUILLADES; LEONARDO EUILLADES; MAURO BLANCO; GABRIEL ALEJANDRO CABRERA; JAN WITTE; JOSÉ LUIS BERGAMASCO

PETROTECNIA

Instituto Argentino del Petróleo y del Gas

Lugar: Buenos Aires. Argentina; Año: 2005 vol. XLVI p. 58 - 68

0031-6598

This work presents a technique named Synthetic Aperture Radar Interferometry (InSAR), used to construct a Digital Elevation Model (DEM). DEM application in structural geology studies is also addressed. The Area of Interest is located at the Sub-Andean section, south of Mendoza province. It is characterized by rough mountains oriented in north-south direction. Synthetic Aperture Radar is a side-looking spaceborne device. The scenes acquired are characterized by serious deformations due to topography, named foreshortening, layover and shadowing. The first two of them can be seen in the image as a shortening and inversion of the slopes facing the SAR antenna. Shadowing means that the slopes opposite to the antenna (with local slope greater than the off-nadir angle) lies in shadow, i.e. no signal coming from them returns to the SAR. To overcome that problems we combined an ascending interferometric pair (south-north) with a descending one (north-south), in order to obtain a DEM covering both east-facing slopes and west-facing ones. Seismic surveys data were used to correct remaining regional error trends. Moreover, seismic stakes were used in order to correct mistakes and regional deformations. The DEM (20m) spatial resolution, obtanied from the satellites ERS 1-2, it allow to calculate the strikes and dip on triangular cells related to nodes of DEM and afterwards graphic them in order to apply them into structural geology studies and models. From a geologic interpretation, stereoplots and a reliable selection of stratification data, it is possible to make applications such us, regional dips, structural trends, curvatures, vergence, and the construction of transectas of high resolution. An application of this method is presented to a real case of an anticline surface, where the results obtained are compared with others from a photo geology analysis. The proposed method constitutes a valuable low-cost tool to carry on quick structural studies over extensive areas.