Abstract
We considered a major factor of variability for the shakeability of long-period ground motion (LPGM) proposed by Yuzawa and Kudo (2011). The proposed empirical model can simply reproduce the response spectrum at a sediment site, combining the attenuation relation for the seismic basement and the site shakeability. However, the shakeability, evaluated as an average for different earthquakes, has a large standard deviation. It has large variability at around periods of 5 to 10 sec. We examined the factors that affect the variability for the shakeability, in order to improve the accuracy of the prediction of LPGM in the Kanto basin. As a result, we found that the period characteristics of the shakeability at each earthquake are dependent on the location of earthquake source. The major factor that affected the variability of the shakeability was the surface wave propagation in Kanto basin. In addition, we showed that the shakeability revaluated for limited regions improves the prediction accuracy of response spectrum of LPGM.
