本研究以台北盆地五個測區以及宜蘭、花蓮各一測區之井下地震儀陣列資料為依據，將各個測站歷年所收到的地震記錄進行頻譜比的分析與比較，探討單站頻譜比法（H/V Ratio）之應用。 在台北盆地我們利用五股工業區污水處理場、蘆洲抽水站、板橋退輔會、板橋水利局以及松山菸廠五個井下地震儀陣列的資料，分別針對背景雜訊（pre-event）與主要能量（S波）之傅氏振幅譜，以及包含了背景雜訊與主要能量等整筆地震記錄之反應譜，進行地表單站頻譜比與地表測站除以井下各測站之雙站頻譜比的分析與比較，且由各測區之岩心柱狀圖，可觀察各測區地表單站頻譜比所反應之地層。 而另外兩測區宜蘭羅東以及花蓮大漢技術學院，由於其有地動加速度值較大之記錄，所以文中將其地動加速度值依據中央氣象局地震震度分級表之分類，觀察其地表單站頻譜比法在不同地動加速度時之變化。 分析比較以上所得之頻譜比值資料，可得到以下結論： 1.台北盆地之地表單站頻譜比不論在S波或是背景雜訊，主要反應出松山層之效應。 2. S波所得之地表單站頻譜比對於地層反應明顯，除了反應第一層外，亦存在其它層之反應，可應用來推求較深層之地下構造，但有時可能會忽略了淺層的地層效應。 3.微地動（pre-event）所得之地表單站頻譜比對於速度對比大之近地表地層有非常明顯之反應，故可將其應用於淺層地層場址效應之研究上，如工程整地，其對於地表之回填土層將會有很好的反應；此外，在地震少之地區，微地動之地表單站頻譜比法乃提供了一個在研究場址反應上快且有效的方法。 4.利用地表單站頻譜比法可看出強地動所造成之非線性效應，故可將之應用於非線性效應之研究上。 This study use the earthquake data recorded by seven downhole accelerometer arrays in Taiwan. Five of the downhole accelerometer arrays are located in Taipei basin and the other two are respectively in Ilan and Hualien areas. First, we cut 5 seconds noise (pre-event) and 10 seconds S-wave from these earthquake data. The seconds, using Fourier amplitude spectrum to transform the noise and S-wave time domain data into frequency domain data. Furthermore, we used response spectrum to calculate the whole data consist of noise and S-wave etc.. Finally, we calculate each site horizontal-to-vertical spectral ratios of surface station (0m H/V ratio) and spectral ratios of surface to different depths station pairs. Compare to the geological profile, we can find out the dominant frequency in the H/V ratio came from which soil layer. The ground motion data recorded by Lotung and Hualien downhole arrays are separated into three groups on the basis of CWB’s intensity scale. The variation of H/V ratio with respect to PGA levels are analyzed in this study. From the spectral ratio obtained through these downhole accelerometer array data, we can summarize the results as below: 1. The fundamental resonance frequencies of H/V ratios at surface stations in the Taipei basin show the response of Sungshan layer. 2. The fundamental resonance frequencies of S-wave H/V ratios at surface stations also can present deeper layer’s response. 3. In the case of high impedance contrast top soil layer, the amplitude and frequency from surface H/V ratio are consistent with that of layer response. 4. The H/V ratio of surface station can use to identify the non-linear soil response.
