Predicting Within-Site Variability of Seismic Site Response Using a Geospatial Modeling Approach

The within-site variability of seismic site response describes the randomness in site response from earthquake to earthquake at a single site. Although the within-site variability of seismic site response can be quantified for seismic stations with certain number of earthquake recordings, it remains challenging to estimate the within-site variability of site response across a large region. This paper aims to provide a geospatial modeling framework for predicting the within-site variability using inexpensive statistical learning methods and geospatial proxies. We obtain the within-site variability data using a large number of earthquake recordings from 114 KiK-net vertical array sites. We examine the predictive power of 18 geospatial proxies associated with site stiffness, topography, basin, and saturation conditions in estimating the within-site variability of seismic site response. The results suggest that geospatial modeling shows promise for evaluating site response across broad regions.