Application of 3D GPR attribute technology in archaeological investigations

Ground penetrating radar （GPR） attribute technology has been applied to many aspects in recent years but there are very few examples in the field of archaeology. Especially how can we extract effective attributes from the two- or three-dimensional radar data so that we can map and describe numerous archaeological targets in a large cultural site？ In this paper, we applied GPR attribute technology to investigate the ancient Nanzhao castle-site in Tengchong, Yunnan Province. In order to get better archaeological target （the ancient wall, the ancient kiln site, and the ancient tomb） analysis and description, we collated the GPR data by collected standardization and then put them to the seismic data processing and interpretation workstation. The data was processed, including a variety of GPR attribute extraction, analysis, and optimization and combined with the archaeological drilling data. We choose the RMS Amplitude, Average Peak Amplitude, Instantaneous Phase, and Maximum Peak Time to interpret three archaeological targets. By comparative analysis, we have clarified that we should use different attributes to interpret different archaeological targets and the results of attribute analysis after horizon tracking is much better than the results based on a time slice.

Archaeological investigation by geotomo-graphy: structure of the foundation of Yingxian timber pagoda

It is significant to take a non-destructive inspection, one of advanced techniques, for detecting the internal structure and the present status of ancient cultural relics. The results detected by geotomography in Yingxian timber pagoda, Shanxi Province, are presented in this paper. The embankment in the stepped foundation shows a three circular structure in horizontal: the circular platform core is hard, homogenous and unharmed, out of which there are some radial collapsed grooves. The middle circle with a thickness of 2 to 4 m is a compacted layer and its loading capacity decreases then. The outer protective layer has a larger porosity and a weak loading capacity. An abnormal body is found out in the core, which has a circular shape and a reverse high-absorption coefficient in the shallow part, but appears a long-band shape and a low-absorption coefficient in the deep part. It might be a disturbance caused by artificial activities: the shallow part is probably a channel filled with loosen soil and the deep part is a hidden cave. It is found that the foundation of the courtyard is homogenous and integrated. Two soft and weakened areas in the north are related to the long-term run-off and drainage of groundwater. The inclination of the timber pagoda to the northwest and northeast relates to several factors, such as the inherited subsidence of the northern foundation, the lower loading capacity of the outer stepped foundation, seismic activity and timber deformation.No.2 FENG R.et al.: ARCHAEOLOGICAL INVESTIGATION BY GEOTOMOGRAPHY