[SSS04-P23] Ground Motion Estimation by using Microtremor H/V Spectral Ratio
キーワード：H/V spectral ratio, site effect, correction factor, ground motion estimation, site characteristic
It has been proved that the H/V spectral ratio method, proposed by Nakamura (1989), is effective in estimating the site response of ground motion. Because the density of strong-motion stations is still insufficient to provide accurate ground motion distribution in a highly developed region. This study proposes a method by using microtremor H/V spectral ratio (HVSR) to correct the site effect and predict the ground motion of nearby sites. Considered two sites at a very close distance and assume that under the influence of the same earthquake, the source and path effect in observed seismic waves are almost the same, the difference ground motion between this two sites just control by their site characteristics, that is the different of their HVSR. So, the ratio of HVSR can be seen as a correction factor to estimate the ground motion of the sites around a strong-motion station. Here, we selected the Ilan plain of Taiwan as a test site, and the seismic records with PGA > 8 gal from 1993 to 2013 were collected to evaluate the error and stability of this method including the relative site distance, hypocenter distance, Vs30, and the spectral different. Finally, the scenarios of several historical events in the Ilan plain were simulated by using the site correction of microtremor HVSR. Consolidate the variations in ground motion for these events to evaluate the effect of site characteristics for ground motion distribution.