Insight on the use of canonical correlation to predict site amplification: application to the Japanese KiK-net network

Abstract

Site specific seismic hazard assessment needs a ground motion amplification model of the investigated region. This model allows to highlight areas that can be strongly affected by earthquake ground motion, which is a crucial information for earthquake mitigation. Site response can be investigated by using technique such as standard spectral ratio, empirical spectral modelling or indirectly through analysis of horizontals-to-vertical spectral ratio (HVSR). The first two techniques are the most powerful, as they allow to retrieve the amplification function of the investigated site by using earthquake recordings, but they require a long observation time to record a sufficient number of events. The HVSR method is instead a simplified method based on the ambient vibration recordings or earthquake recordings. The HVSR is generally used to retrieve mainly the fundamental frequency of the site, while its amplitude as a function of frequency is not considered as directly representative of the site amplification. Here, we apply a method based on the statistical technique of the canonical correlation (CC) to link the amplitudes of HVSR and the earthquake site response. We test this approach on the measured amplification functions at 428 seismic stations of the Japanese KiK-net network. We show that the estimated CC coefficients can be used to reconstruct the expected amplification function at sites where only HVSR is available.