A Comparison Study of the Dynamic Amplification Characteristics of the Major Domestic Seismic Observation Sites using Background Noise and S-wave Energy of Ground Motions from 15 Fukuoka Earthquakes Series

Abstract:

Observed ground motions are mainly composed of 3 main factors such as seismic source, seismic wave attenuation and site amplification. Among them, site amplification is also important factor and should be considered to estimate soil-structure dynamic interaction with more reliability. Though various estimation methods are suggested, this study used the method by Castro et. al.(1997) for estimating site amplification. This method has been extended to background noise, coda waves and S waves recently for estimating site amplification. This study applied the Castro et. al.(1997)'s method to the background noise. This study analysed more than 298 background noises from 15 macro earthquakes including main Fukuoka earthquake (2005/03/20, M=6.5) and then compared to results from S waves(2013), at 8 main domestic seismic stations. The results showed that most of the domestic seismic stations gave similar results to those from S waves(2013). Each station showed its own characteristics of site amplification property in low, high and specific resonance frequency ranges. Comparison of this study to other studies can give us much information about dynamic amplification of domestic sites characteristics and site classification.