Ground penetrating radar applied to monumental stone conservation: application to the rock necropolis of San Vítor de Barxacova in NW Spain

Abstract

This paper deals with the application of the Ground Penetrating Radar (GPR) method in the assessment of stone monuments. Compilation of published works and a discussion of their main findings are first addressed. Next, to show the potential of the method, a case study is presented aiming to assess the state of conservation of the rock necropolis of San Vítor de Barxacova (Ourense, Spain) consisting of 56 anthropomorphic graves carved into the natural rock. Fieldwork was carried out using a GPR system equipped with a 2.3 GHz central frequency antenna. The main goal of this study is to provide an effective approach for the detection and localization of internal damages such as fractures and voids. New amplitude-based 2D and 3D imaging strategies are presented aiming to improve damage detection. A new approach was also developed to digitize the extracted information into a point cloud format, thus improving the possibilities for 3D visualization with the surrounding environment. Although a total of 39 graves were surveyed, only 13 graves are included in this paper due to their singularity and relevant results. The potential of using GPR tests for the assessment of the conservation state of monumental stone structures is also discussed.