SITE AMPLIFICATION ESTIMATED FROM EARTHQUAKE MOTION RECORDS WITH APPARENT INCIDENT ANGLE

Abstract

The site amplification factors due to deep sediments are evaluated using earthquake motion records observed in the Kanto Plain. The observed amplification factors almost agree with the one-dimensional amplification factors computed from the deep underground structure when the earthquake source is located beneath the basin. On the contrary, in case that the source is situated outside of the basin, the observed amplification is much larger than the computed one. This is because that the mechanisms of seismic basin response depend on the location of earthquake sources.