Análise e processamento de dados de GPR de uma porção da barreira holocênica da planície costeira do Rio Grande do Sul - Brasil

Abstract

Ground Penetration Radar (GPR) is a geophysical method which uses electromagnetic energy transmission, reflection and reception to probe the subsurface. GPR data demands analysis and processing to create images. The main purpose of GPR data processing is to overcome the acquisition limitations using corrections and analyses to construct an understandable and reliable product. Accordingly, the present work aims at analyze and process GPR coastal data, and build a processing routine to improve image quality. The data set used for this work contains six GPR sections, which were acquired at the southern portion of the coastal barrier of Santa Vitória do Palmar – RS, Brazil, with NW-SE orientation (perpendicular to the coastal barrier). Those section have an average length of 500m and parallel spacing of 50m. During the acquisition was used the GSSI (geophysical Survey Systems, Inc.) 200MHz antenna for a common offset survey. In addition, topographic data were collected during the GPR survey. Different processing techniques were tested, and a selection was built based on the technique performance for the coastal data. A significant improvement was noticed when the following techniques were applied: band-pass filter, improving the signal to noise ratio; gain control, enhancing the signal amplitudes, which was attenuated by the geometrical spreading of the signal and topographic correction, responsible to correct reflectors’ positions by moving traces vertically. In conclusion, the processing routine used for the data set has improved significantly image quality, allowing a reliable and better interpretation.