Preliminary investigation on the preservation of Machu Picchu ruins: Discussions from topographical and geological aspects

Abstract

Machu Picchu is undoubtedly the most famous ruin of the Inca Empire. It is located northwest of Cuzco, the former capital of the Inca Empire, and east-southeast of Lima, the current capital of the Republic of Peru. The ruins are located on a narrow ridge (N15W) between Mt. Machu Picchu (elev. 3060m) on the south and Mt. Huayna Picchu (elev. 2660m) on the north. The site has been investigated by a Japanese mission comprised of experts in archeology, city planning, structural engineering and seismic engineering, seismology, geology and soil engineering. The results of topographical and geological investigations of the site indicate: 1. Construction of the ruins took advantage of topographical conditions and large-scale reconstruction is not feasible. 2. The base rock of the site consists of granite. In situ construction used materials from the local base rock. 3. Colluvial soils exist on the gentle slopes. Their current condition suggests that they were recently formed. 4. As long as there is not a great earthquake or especially heavy rainfall, there is little probability that serious damage will occur from the foundation.