Dilatometric and Extensometric Monitoring of Rock Blocks Displacements Within Machu Picchu Archaeological Site, Peru

The area of archaeological site of Machu Picchu was affected by large-scale slope movement in the past. This event in the paleogeomorphological evolution of the area, along with intensive fluvial erosion and tectonic disturbance of the rocks, has been significantly affecting the evolution of the landscape. Unknown triggering impulse for such huge slope deformation and presence of several younger generations of slope movements were reasons for complex geological – geomorphological investigation aimed to verify the potential recent activity of deep-slope movement. In order to understand the mechanism and recent activity of the mass movements the monitoring net of dilatometric and extensometric measurements was established during 2002, after preliminary field investigation in 2001 and aerial photo interpretations. The results of the monitoring supported by the field investigation suggest that large-scale slope movement is doubtful in close future. Nevertheless, continuation of monitoring will be useful and from point of view of the long-term landscape evolution the area is in unstable position. The recent detected movements can be explained by individual movements of rock blocks or several other mechanism including subsurface erosion and local sinking and deformation of archaeological structures.