RELATIONSHIP BETWEEN GROUND STRUCTURE TO SEISMIC BEDROCK AND DEPENDENCY OF AMPLIFICATION FACTOR ON EARTHQUAKE MAGNITUDE

Abstract

An effect of not only subsurface structure but also deep ground structure on an amplification factor depended on earthquake magnitude is investigated by using records of KiK-net observation sites where information of ground structure to seismic bedrock is already obtained. Relationship between moment magnitude (M_w) of an earthquake and an amplification factor is examined at each observation site. The relation is not clear at observation sites with low fundamental frequency in transfer function. Since the transfer function at observation sites of thick sedimentary layer is amplified in broadband frequency range regardless of an earthquake magnitude, it is conceivable that the amplification factors at their sites are little dependent on earthquake magnitude.