Characterization of the Karstic Process in an Urban Environment Using GPR Surveys

In this work the authors present an analysis of the applicability of ground penetrating radar (GPR) to karstic hazard evaluation in urban areas by means of several case studies. The main objective is to characterize the origin of pathologies in buildings and other facilities, and of subsidence processes, and to identify their causative phenomena in the subsoil. This study involves the analysis of resolution, penetration characteristics and noise affecting GPR signals in urban areas. The analyzed case studies are located in the Central Ebro Basin (NE Spain), where the main hazards are related to mantled karst (solution of evaporites below alluvial deposits). The studied examples show that in areas affected by karst activity with medium to high subsidence rates, interpretation of GPR profiles allows defining collapses, subsidence, surficial repairs (either historical or recent) and underground cavities.