Example of study showing the value of a composite image of GPR reflection amplitude across a burial mound.
Goodman et al. (2006, 2009) presented advanced analysis of detailed GPR data collected over burial mounds in Japan. An example of a mound is shown in Fig. 1. Fig. 2 shows a typical GPR profile across the mound corrected for topography and antenna tilt. Fig. 3 shows a composite image of the strongest reflections on several time slice maps that shows a keyhole-shaped moat dug around the burial mound.
Fig. 1. Photograph of the interior of a burial mound in Japan. Entrance to burial chamber appears in photograph center. The mound has a relief of several meters and is surrounded by a keyhole-shaped moat that was impossible to detect without GPR.*
Fig. 2. GPR profile of a burial mound that has been corrected for topography and tilt of the antenna. Dashed lines perpendicular to surface show the ray paths used in tilt correction of antenna scans at the associated surface points. Bright red zone under and slightly offset to right of mound peak is the subsurface chamber void. *
Fig. 3. Composite image of GPR reflection amplitude across the burial mound. This is constructed by summing the strongest reflections from individual time-slice amplitude maps collected by different antennas between depths of 176 and 344 cm. The chamber void is near the center of the keyhole at its broadest. The keyhole-shaped moat was not visible at any one depth but became apparent when bright reflections from several depths were summed. **
* Goodman, D., Nishimura, Y., Hongo, H., and Higashi, N., 2006, Correcting for topography and the tilt of ground-penetrating radar antennae: Archaeological Prospection, v. 13, no. 2, p. 157-161
** Goodman, D., Piro, S., Nishimura, Y., Schneider, K., Hongo, H., Higashi, N., Steinberg, J., and Diamiata, B., 2009, GPR Archaeometry, in Jol, H. M., ed., Ground Penetrating Radar Theory and Applications Amsterdam, Elsevier, p. 479-508.