Geological structures evaluated by means of scattering noise in ground penetrating radar images

摘要

Coastal geology in Barcelona City is formed by Quaternary sediments overlying Tertiary strata. The Quaternary plane is crossed by paleochannels and streams, all of them under the city structures and constructions. Boreholes demonstrate differences in the grain size distribution of the materials from the different geological structures. In this work, Ground-penetrating radar was proved as a tool to obtain quick information about these changes. The results from more than 20 km of GPR profiles in Barcelona city, seems to indicate that, depending on the relationship between the wavelength and grain size, GPR signal scattering increases significantly. Therefore, the analysis of the noise in GPR signals supplies information to determine the possible existence of geological changes in the quaternary deposits. Several tests and measures in well-known emplacements, as well as models and simulations, were used to determine the ability of this method in the study of the Barcelona plain shallow geology. Correlation between paleochannels and infilled streams and higher scattering noise is observed in this study. The analysis of the scattering effect on the amplitude of the radar data could help to locate paleochannels and subterranean infilled streams, being a valuable tool to improve the knowledge of the city subsoil.