We use the common earthquake datas of the two stations and very intensive microtremor measurement in HsinYi area to investigate and discuss the site effect of the two stations especially. Then compare our site effect map with and SunShan thickness and velocity maps for discussing the ground motion characters of the two sites and their possible reasons.
We find that using microtremor measurement can get a well fit in site effect and SunShan thickness maps；and we make sure that SunShan thickness controls the site TAP022’s low frequency（1∼2Hz）site effect, no matter what the earthquake’s energy pass this area, the horizontal component will enlarge especially about 1Hz.
This research also verifies that using microtremor measurement is a good geophysical method for estimating the site effect of alluvium. By the way we can apply those site effect estimation for seismic hazard analysis.
