ABSTRACT
In the Great East Japan earthquake of 2011, long-term settlement in the alluvial clay ground was observed in Miyagi Prefecture. And, a similar settlement was also observed in Niigata Prefecture Chuetsu-Oki Earthquake of 2007. The ground investigation revealed that this alluvial clay ground is composed of structured clay. It is thought that long-term settlement is caused by deterioration of this structure. In addition, ground motion may be amplified in the structured clay ground. Therefore, centrifuge model tests were conducted to reveal the mechanism of long-term settlement due to earthquakes and seismic amplification of clay ground.
