GPR survey to confirm the location of ancient structures under the Valencian Cathedral (Spain)

This paper describes the ground-penetrating radar (GPR) survey performed in side the Cathedral of Valencia, Spain. It is part of historical studies per formed in the Cathedral in order to add information to old maps and documen ts in the Cathedral Archives and also to analyze the extent and importance of potentially destructive moisture areas that were appearing on the floor. The construction of the Cathedral of Valencia occurred in three stages, al l of which are well-documented in the Cathedral Archives with detailed draw ings, maps, and charts. The radar data were successful in locating crypts, ossuaries, sepulchers, and graves, and the location of ancient walls that e xisted before the final Cathedral expansion. Three cultural layers correspo nding to the three periods of construction were also identified correspondi ng to the Roman, Arabian and Middle Age Epochs. Measurements of relative su b-floor moisture were obtained by comparing dielectric permittivity changes and radar velocity differences between materials in humid and non-humid ar eas. (C) 2000 Elsevier Science B.V. All rights reserved.