ABSTRACT
In the 2004 Niigataken Chuetsu earthquake, a large number of houses were damaged by ground deformation. In particular, at the Takamachi housing complex in southeast Nagaoka City (as shown in Fig. 1), the ground deformed significantly in a fill area, and artificial fill slopes around the complex suffered considerable collapse. Damage to houses caused by ground deformation had been repeatedly observed in past earthquakes such as the 1978 Miyagiken-oki and the 1995 Hyogokennanbu earthquakes. Since flat land in Japan is limited, the cut and fill technique is widelly applied to the development of housing complexes. Consequently, it is important to investigate the correlation between damage to houses and the ground conditions of cut and fill areas. Artificial fill slopes in valleys and levees are also often reported to collapse in earthquakes. At the Takamachi housing complex, artificial fill slopes suffered significant collapse at four sites in the area surrounding the complex.
