Landslide Risk Assessment at Cultural Heritage Sites

Many cultural heritage sites such as castles, palaces, monasteries, temples and other important buildings have been constructed on or close to slopes. Once-stable slopes may become unstable over time through rock weathering, deformation by tectonic stress, and river erosion at the toe. Human activities such as mining, ground-water pumping, or irrigation may affect slope stability too. Some apparently stable slopes may be at risk of failing due to triggering factors such as earthquakes, or pore pressure rise during rain or snow melt. Sometimes slope creep can result in strength reduction in the potential shear zones and failure, even without strong triggering factors. This paper reports on activities for landslide risk assessments at three major cultural heritage sites in China (Lishan, Xian), Peru (Machu Picchu), and Japan (Unzen volcano). A series of studies have been conducted at these sites since 1991 as a part of the International Decade for Natural Disaster Reduction (IDNDR), the International Geoscience Programme (IGCP) and the International Programme on Landslides (IPL). The success of the landslide hazard assessment at the cultural heritage site in Xian, China greatly contributed to the establishment of ICL and IPL.