Gpr Survey Discovers Lost 1St Century Ad Roman Amphitheater

Abstract

A ground penetrating radar survey was conducted over a dirt parking lot and part of a farm at a site in the Tiber Valley, northeast of Rome. The site is situated next to a completely restored 1st century AD church and a partially reconstructed marketplace known as the Forum Novum. Using a 500 MHz radar antenna and closely spaced radar profiles, time slice and 3-D volume analysis of the reflection data using GPR-SLICE Software revealed a large oval reflection 45 meters along the major axis. This reflection is interpreted to be a Roman amphitheater that had gone undetected next to the reconstructed first century ruins. The time slices also revealed completely different top layer reflections from structures associated with destroyed mausoleum, which could also be seen by the naked eye as cropmarks. Archaeologists often reconstruct subsurface archaeology based on cropmarks. In this case however, radar was able to detect structures near the surface and a much different set of structures lying deeper using time slice analysis. Archaeologist from the University of Birmingham recently excavated one of the eight entrances into the amphitheater that was imaged in the data (see www.gpr-survey.com ). Excavations reveal that the amphitheater oval is nearly a meter thick and is composed of a cemented stone wall buried 60 cm below the ground surface.