Abstract
On March 20, 2005 the West off Fukuoka earthquake of MJ7.0 occurred at about 30km northwest of Fukuoka City. Although 6- on the JMA seismic intensity scale were reported at several points in Fukuoka, structural damage was not so devastating as expected from this intensity. Still, we have clear concentration of the damaged buildings in the central part of the city. Thus, we analyze the observed strong motion record in Fukuoka. First basic characteristics were summarized, and then the structural damage potential of these strong motions (=destructive ability) was evaluated using the damage ratio prediction model, in which we use a nonlinear response analysis method for a set of structures with different strengths (so-called Nagato-Kawase model). Then, the damage ratio distribution was calculated using the strong motion waveforms reproduced from the 1-dimensional ground models reflecting the shallow soil layers down to the engineering bedrock at every small districts. It turned out that the damage ratios also becomes large, as observed, in the areas where the bedrock depths are deep, namely in the northeastern side of the Kego fault. However, the simulated damage ratios are larger than the observed damage ratios so that we have a space for improvement in our simulation model of damage.
