SOIL NONLINEARITY AND BEDROCK STRONG MOTIONS ESTIMATED FROM DOWNHOLE ARRAY RECORDS AT KASHIWAZAKI-KARIWA NUCLEAR POWER PLANT DURING THE 2007 NIIGATA-KEN CHUETSU-OKI

• DOI: 10.3130/aijs.73.1273
• Publication Date: 2009-09-30T05:59:58Z
• Authors: Kohji TOKIMATSU; Hiroshi ARAI; Kentaro MINOWA
• Keywords: Bedrock

Nonlinear soil properties as well bedrock outcrop strong motions are back-calculated using 4-depth downhole recorded at the Kashiwazaki-Kariwa nuclear power plant during 2007 Niigata-ken Chuetsu-oki earthquake. Adopted in inverse analysis genetic algorithms (GA) combined with a 1-D equivalent-linear response which strain-dependent damping ratios assumed frequency domain. The inversion results show that surface layer down to depth of 70 m exhibited nonlinear behavior shear modulus ratio about 0.01 and up 35%.