SIMULATION OF STRONG GROUND MOTIONS USING EMPIRICAL SITE AMPLIFICATION AND PHASE CHARACTERISTICS

-MODIFICATION TO INCORPORATE CAUSALITY-

Abstract

  The strong motion simulation technique using site-dependent amplification and phase characteristics was originally proposed by Kowada et al. and its applicability has been extensively studied by the authors. One disadvantage of the method, however, was that it cannot generate a ground motion that satisfies causality conditions, meaning a ground motion with zero amplitude at the beginning of the time history. In this article, the authors revise the method by introducing a smoothing technique in the procedure to generate Green's functions. It was confirmed that the revised method can generate causal ground motions, which are in agreement with the observed ground motions during the 2003 Tokachi-oki earthquake.