[SSS15-P06] Study on spectral decay characteristics in high frequency range of observed records during The 2016 Kumamoto Earthquakes
Keywords:The 2016 Kumamoto Earthquakes, Spectral decay characteristics, fmax filter, Kappa
In result, fmax’s of large earthquakes are estimated to be 7Hz to 10Hz and the larger earthquakes are, the smaller fmax’s tend to be. The power coefficient of fmax filter, s, of largest foreshock and mainshock of the 2016 Kumamoto Earthquake are larger than those of large earthquakes occurred in other region. From this result, a region dependency of spectral decay characteristic is suggested.
κ’s of large earthquakes are estimated to be 0.0466 to 0.0482. There are positive correlation between s as power coefficient of high-frequency decay of fmax filter and κ as spectral decay parameter and between fmax for the fmax filter and fE for parameter κ. fE is a frequency at which spectrum starts to decrease on log-linear scale. fE is a very important parameter for strong ground motion prediction, however fE has not been examined carefully enough in previous κ studies. It is confirmed that evaluated high frequency characteristics by fmax filter and those from spectral decay parameter, κ agree well with each other.