Abstract
The Niigataken tyuetu earthquake of magnitude 6.8 occurred on October 23, 2004, and the cause was considered. The relation between the excellence cycle of the ground compared with H/V and the thickness of the layer of the subsurface layer was clarified. It has been understood that the excellence of the alluvium corresponds to the second peak compared with H/V. Moreover, making the ground nonlinear was admitted from the seismic response analysis in the offing product terrace layer.
