一般以地震訊號研究邊坡表層的構造變異，主要的研究方法是以頻譜比法計算出邊坡場址效應之頻譜圖後，再觀察構造變異產生前後顯著頻率的變化以及對應頻率振幅的改變。而Del Gaudio 於2007年的研究中藉由實際的地震觀測資料提出，邊坡的場址效應會隨著不同的方位角而有不同的放大效應，而根據他的研究結果，在某些特定地形和地質構造的邊坡上，可觀察到朝特定方向有集中放大的現象。本研究的目的是希望藉由觀察邊坡場址效應之方向性，找出地質構造產生變異時所對應之方向性在時間與空間上的變化。
本研究區為屏東縣士文水庫預定壩址，該地區共有三個強震測站，其中位於邊坡上之SW-1測站於莫拉克風災期間，周圍產生明顯的大型裂隙，因此選作為主要的研究場址。研究方法為將測站所接收到之地震加速度歷時以旋轉矩陣的公式計算出水平向不同方位角之加速度歷時並選取其尾波時段，藉由單站及雙站頻譜比法繪製出平均方位角頻譜圖後，找出該場址之顯著頻率區間並以該區間頻譜比之最大值所對應之方位角作為該次的場址效應方向，藉由觀察每筆地震紀錄之場址效應方向性，找出與裂隙產生前後所對應之變化。
從單站法的結果發現SW-1測站所在之場址顯著頻率約在2.3至4.3Hz之間，而場址效應之方向性主要為南北向，與邊坡傾向平行，而根據觀察每筆地震紀錄之方位角變化發現，在裂隙產生前方位角角度的分佈是相當的集中，標準差介於4.8~8.0度之間，裂隙產生後方位角角度的分佈則變得發散，標準差介於8.1~16.8度之間。根據Del Gaudio的研究結果推測，這可能是因為裂隙的產生使得邊坡場址的地質構造狀況產生變異，導致震動能量的分配情況改變便所造成的尾波複反射或散射狀況。因此對於測站鄰近地區之地下裂隙改變或是產生，本方法可以提供在不增加現地儀器設備之下的偵測功能。

Recent research has found that the maximum amplification direction of slope site response is oriented along local topographic features, and such directivity phenomena is caused by a combination of topographic, lithologic and geologic factors. The purpose of this study is to find the variation of the slope site response directivity which is dependent on the change of slope geologic condition by observing the spectrums of seismic coda wave which were recorded across the happen of changing event.

The seismograph set on the slope at planned Shin-Wen Reservoir site, southeastern Taiwan is chosen for this research because there was a fracture zone occurred near the station during Typhoon Morakot at 2009. By rotating the pair of horizontal seismograms and calculating with HVSR and SSR methods to get the directivity of slope site response. According to the results of each seismic record, it shows that the azimuths of directivities are distributed along about N0°E. However, the distribution of azimuths after the fracture occurred is much scattered than before the occurrence of fracture. This research suggest that the phenomena may cause by the occurrence of the fracture which had changed the slope physical condition of geological material. This method might be able to detect the existence of subsurface fracture near the station.

吳重儀 (2014)，近場址地震波頻譜與地下裂隙關聯分析研究，國立成功大學資源工程研究所碩士論文。
吳啟新 (2015)，裂隙狀態對震波場址效應影響分析，國立成功大學資源工程研究所博士論文。
林子翔 (2012)，以微地動量測方法研究順向坡之放大與極化效應，國立中央大學應用地質研究所碩士論文。
經濟部水利規劃試驗所 (2010)，士文水庫可行性規劃-強地動儀維護觀測及資料整理。
經濟部水利規劃試驗所 (2012)，地震波頻譜分析壩體共振頻率與參數變異之探討。
經濟部水利規劃試驗所 (2015)，後龍溪水資源環境觀測及調查計畫-強地動儀維護觀測及資料整理。
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