A Special ERT-3D Array Carried Out to Investigate the Subsoil of the Pyramid El Castillo, Chichen Itza, Mexico

Researchers identified a low-resistivity body beneath the Pyramid El Castillo at Chichen Itza, Mexico, suggesting the presence of a sinkhole filled with sweet water. This finding builds on previous ground-penetrating radar (GPR) studies that hinted at man-made tunnels in the limestone subsoil. To investigate this further, scientists employed a specialized 3D electrical resistivity tomography (ERT-3D) array, using 96 flat-surface electrodes arranged in a square geometry around the pyramid. This method allowed for 8,500 apparent resistivity observations across a depth of 25 meters, providing a detailed subsurface profile. The study highlights the potential of ERT-3D arrays to overcome challenges posed by traditional geophysical methods when applied to ancient structures, offering new insights into the hidden complexities of UNESCO World Heritage Sites.

Chavez, R. E., Tejero, A., Cifuentes, G., Argote, D. L., & Hernandez, J. E. (2015). A Special ERT-3D Array Carried Out to Investigate the Subsoil of the Pyramid El Castillo, Chichen Itza, Mexico. Near Surface Geoscience 2015 - 21st European Meeting of Environmental and Engineering Geophysics. https://doi.org/10.3997/2214-4609.201413794