在地質構造複雜的台灣，各類場址對於地震之放大效應影響極大，區域性的場址效應微分區為重要之研究。台灣東部地區，處於歐亞板塊與菲律賓海板塊交界帶，地震發生頻繁，本延續性計畫今年度將探討花東縱谷地區之場址效應微分區研究。花東縱谷北起於花蓮，南延至台東，介於中央山脈與海岸山脈間，為一南北延展之狹長谷地平原。由於無基盤岩層出露，甚難估計沖積層厚度，但可能超過數百公尺（楊榮堃，1990）。黃雋彥（2007）以微地動探討花東縱谷地區之主頻分佈，顯示花東縱谷地區呈現中段主頻較高，而往南北皆呈現較低現象，整體來說仍為北低南高趨勢。結果顯示花東縱谷地區之場址南北有不同的放大特性，值得我們進行探討。本研究主要目的為建立區域之場址效應微分區，因此除不同地震對區域性之場址放大倍率分佈外，微地動的主要頻率分佈將成為本研究微分區之重要參考，同時建立台灣花東縱谷地區之場址放大係數與土層係數之關係，作為防災應用及耐震設計之參考。 The improvement of structural seismic design, which needs a proper definition of seismic demands for different site conditions, can efficiently prevent the damage of structures from the earthquake excitations and is the best way for earthquake hazard mitigation. The Central Weather Bureau has installed a very dense ground-motion array in Taiwan. We used these earthquake data collected in the last decades to investigate the local site effects and its influence in the ground shaking for the East Taiwan (East Rift Valley). Based on the attenuation relationship, which was modified by the records of reference sites to eliminate the source and path effects by events, the site effects of each TSMIP station in the study area were discussed in terms of an amplification factor to the reference sites (hard sites). The ground motion amplification factors that incorporate more detailed information on site conditions can be used to remove bias and reduce the uncertainly of ground motion estimates from the attenuation relationship. All results will be provided for microzonation of site effect and improve the methodology for a better earthquake hazard mitigation purpose. 研究期間：9901 ~ 9912
