In this study we developed a new ground motion prediction equation (GMPE) of the seismic intensity measure to evaluate structural damage to houses and buildings for crustal earthquakes in Japan using strong ground motion records. The seismic intensity is calculated using 1-1.5 second 20% damped response spectra, which is the equivalent period and damping when houses and building are damaged severely. Causes of the large 1-1.5 second response are revealed by analyzing residuals between predicted values and the observed ones.
Results obtained in this study summarized as follows.
1) GMPEs with three types of distance, the hypocentral distance, the fault distance and the strong ground motion generation area (SMGA) distance were developed. The GMPE with the hypocentral distance underestimated near fault records.
2) We examined the influence of the velocity structure model and developed correction terms using deep sedimentary layers and shallow soft soils. The estimation accuracy was improved by applying correction terms.
3) We examined the inter-earthquakes variation. We found that the 1-1.5 responses of reverse faults are larger than those of strike-slip faults. The 1-1.5 responses of buried ruptures are larger than those of surface ruptures. Depth dependence was not clear.
4) We also examined the intra-earthquake variation. The directivity effect and non-linear response of shallow soft soils are causes of intra-earthquake variation.
In the future, we will examine the relationship between the 1-1.5 response and the velocity structure model in more detail. We will also consider how to use the GMPE developed in this study for the earthquake damage estimation.
