抄録
A strong earthquake with JMA (Japan Meteorological Agency) magnitude of 6.8 occurred with its epicenter located in Chuetsu-oki in Niigata Prefecture, on July 16 2007. This earthquake caused extensive damage, completely destroying about 1,000 homes, triggering 105 landslide disasters, and damaging 1,090 agricultural facilities and peripheral facilities of a nuclear power plant. The damage included a shield tunnel used as a drainage canal: damage unprecedented in Japan. This paper reports the results of a detailed survey of this damage, and describes dynamic response analysis carried out using near-source seismic waves. The cause of damage is considered to be the topographical effects of the shape of the mountain above the underground shield tunnel. In the future, it will be necessary to perform seismic design carefully in areas with similar topographical conditions.
