Characterization of the rio grande rise from elements of the terrestrial gravity field

Abstract

The aim of this paper is to investigate the structural characteristics of the Rio Grande Rise, South Atlantic, through the analysis of the elements of the terrestrial gravity field. We used sea surface height (SSH) data and calculated sea surface gradients (SSG) from the ERS1-GM, Geosat-GM and Seasat satellite missions. By analyzing the sea surface heights it was possible to identify larger structures, such as the rift of the rise, some fractures and large seamounts. Sea surface gradients provided greater details of the features characterized by the SSH and, additionally, of the entire area, also revealing several other structures related to short wavelengths. The positioning of the features identified by both SSH and SSG is fairly accurate. Factors such as the direction and the orientation of the satellite tracks and the presence of adjacent structures may influence the SSG response to a given tectonic feature, making it important to analyze both ascending and descending sets of tracks from several missions to obtain better results. The study also allowed us to identify possible structures with a characteristic response of seamounts on SSH descending tracks, which were not previously characterized in the literature and do not have a similar correspondent in topographic/bathymetric models.