A team of international researchers has employed an integrated approach to uncover the mysteries of the Eastern Mausoleum of Qin State, an ancient royal burial site from China's Warring States period.

By combining satellite imagery and electromagnetic ground surveys, the study offers a fresh perspective on the burial practices and cultural heritage of ancient China, while simultaneously pushing the boundaries of non-invasive archaeological research.

The study was published in the Heritage Science on October 14, 2024.

Satellite data from sources like Corona and SDGSAT-1 helped identify key features from space, while ground-based electromagnetic (EM) tools were employed to detect underground structures. Vegetation and soil anomalies were detected using indices like NDVI (vegetation health) and NDMI (moisture levels). These combined methods allowed for a more comprehensive view of both the surface and subsurface features of the site.

Led by Prof. CHEN Fulong from the Aerospace Information Research Institute (AIR) under the Chinese Academy of Sciences, the research team found that remote sensing technology was highly effective in identifying soil and vegetation changes linked to buried archaeological features.

Using thermal infrared data from the SDGSAT-1 satellite, the team detected subtle temperature differences, suggesting hidden tomb passages. EM prospecting confirmed the existence of ancient structures like tomb chambers. This approach revealed the precision of ancient Chinese site-selection practices and demonstrated the effectiveness of integrated observation methods.

"The Eastern Mausoleum is a remarkable piece of our heritage, and with the integration of space and ground-based technologies, we have uncovered details that were previously invisible," said Prof. CHEN.

Field investigations confirmed many of the findings from satellite and EM data. Researchers explored the soil structure around the mausoleum and found distinct layers, with deeper layers showing signs of human intervention. This suggests that ancient builders used specific techniques, such as rammed earth, to stabilize tomb chambers and protect them from environmental damage.

A detailed analysis of the landscape showed that the Eastern Mausoleum followed traditional Chinese Feng Shui principles, such as "mountain behind, water in front." The tomb is located on an elevated loess terrace, offering protection from floods and reinforcing its symbolic and strategic importance. Rivers and natural drainage further supported the suitability of the site.

Their findings not only emphasize the archaeological significance of the site but also demonstrate the effectiveness of space-ground observation methods in safeguarding cultural heritage sites.

"This approach could serve as a model for future archaeological studies, enabling us to study large, ancient sites without disturbing their integrity," said CHEN.

The field survey of the research team related to the rammed earth layers. (Image by AIR)