Vulnerability of Machu Picchu citadel 100 years after its scientific discovery

摘要

In the year 2011, Peru celebrates 100 years since Hiram Bingham discovered the citadel of Machu Picchu. The Inca citadel of Machu Picchu has become the most famous historical site in Peru; the site was declared as world cultural heritage by UNESCO in 1983 and also as one of the New Seven Wonders of the World in 2007. All of its constructions are made of stone masonry, and during almost four centuries the citadel endured and survived under a thick rain forest, until it was discovered in 1911. This paper attempts to describe mainly the seismic vulnerability by observing the structural conditions of historical stone buildings which are located in the citadel. The Andean region of Peru corresponds to a zone of low seismic activity however, these low intensity earthquakes could produce damage in the stone constructions. Moreover, the present structural conditions of some buildings lead one to think that these constructions have been subjected to the action of past earthquakes or other geodynamic actions. The characteristics of failures are discussed in this paper, through field survey, micro vibration measurements and dynamic analysis. The field survey on damage consisted of a detailed observation and evaluation of a group of selected buildings. Also, micro vibration measurements were performed on the ground and on some buildings to estimate their dynamic characteristics.