一筆地震紀錄資料中包含震源機制效應、傳遞路徑效應以及接收站周圍的地層場址效應，三者在頻率域下的乘積則構成一完整地震訊號。不同的地震事件會造成相對應的震源與路徑效應，但在單一地質狀態沒有太大改變的地震測站中，場址之顯著頻率則會維持不變，因此，觀察濾除震源及路徑效應後的訊號特徵可以了解鄰近的地質結構狀態。Panzera and Lombardo et al. (2013) 將影響場址效應之因子分成三類，(1)地形形態特徵 (2)沉積層速度構造與幾何 (3)地下水、崩塌堆積、不連續面構造與地下洞窟等，過去較多的研究著重在前二者，而分析地下特定構造之共振頻率相關研究近日亦成為一新鮮主題，然而本研究更將地震場址效應應用於地質結構變異之動態分析。

本研究分成三個主要部分，(1)邊坡裂隙效應，在屏東縣春日鄉研究區中，一邊坡經過莫拉克風災後產生長52m深5m之裂隙，比較其災前與災後之地震場址效應，推估該不連續面之顯著頻率為14.5–17.5Hz。(2)斷層錯動效應，蒐集車籠埔斷層周圍測站長時期(1995–2010)資料，分析其在921地震前與後之共振頻率變異，結果顯示近斷層測站在集集地震後變異較為明顯，並在9年內漸漸恢復至初始狀態。(3)使用強震站中背景訊號分析斷層效應，將地震測站中P波前之空白訊號部分作為環境噪訊，討論其能夠反映構造場址效應之能力及穩定性，結果顯示該訊號亦能反映出共振頻率，但多數資料受限於不足的訊噪比，實用性仍有待討論。透過本文之討論，提供使用地震場址效應偵測不連續面構造狀態之參考，並增加直接利用地震訊號評估災害潛勢之可能性。

An earthquake signal contains data of the source, transmission path, and site effect around the receiving station. Convolution of the three effects could constitute a complete seismogram. Different seismic events might cause corresponding source and path effects, but for a single station that sees little change in its geological substructures, the significant frequency will generally remain unchanged. Therefore, obtaining the signal features that filter out source and path elements could aid understanding of local geological structures. Panzera and Lombardo et al. (2013) sort the factors that contribute to the site effect into three major categories: (a) effects linked to topographic and morphologic features; (b) effects linked to typology and geometry of sediments; and (c) effects linked to the presence of water, landslides, structural discontinuities, and cavities. Most previous researchers focused on the first two factors. Additionally, analyzing the seismic resonance frequency associated with the presence of specific subsurface structures has recently become topic of interest. However, to increase the applicability of the site effect, this study aims to determine the resonance frequencies related to structural variations.
This study is divided into three main sections. (1) Crack effects on a slope are investigated in Chunrih Township, Pingtung County, where a 52 m long, 5 m deep crack was produced by the 2009 typhoon Morakot. Analysis results show a notable band at 14.5–17.5 Hz after the disaster. (2) The fault movement effect is investigated using long-period earthquake data (1995–2010) from the stations around Chelungpu fault, analyzing the change of resonance frequency after the Chi-Chi earthquake. Stations neighboring the fault show significant disturbances, and station TCU129 shows a gradual shift back to the original state over nine years. (3) The applicability of computing site response from the background noise at earthquake stations is assessed. Results show this signal could reflect peak frequencies as S-wave bands, but most data are limited by an insufficient SNR, thus practicalities need further discussion. This study has demonstrated the potential of these methods in assessing the states of near-field discontinuities directly using earthquake data.

Baratta, M. (1910). La catastrofe sismica Calabro-Messinese (28 dicembre 1908). Società Geografica Italiana, Rom, 458 p.
Bardet, J. P., Ichii, K, and Lin, C. H. (2000). EERA, a computer program for Equivalentlinear Earthquake site Response Analyses of layered soil deposits. University of Southern California, Department of Civil Engineering, User’s Manual, 38p.
Barnaba, C., and Vuan, A. (2012). Local Site Response in an Alpine Valley from Recorded Earthquakes and Ambient Noise Analysis. B. Seismol. Soc. Am., 102(5), 2225-2231. doi: 10.1785/0120120092
Barnaba, C., Priolo, E., Vuan, A., and Romanelli, M. (2007). Site effect of the strong-motion site at Tolmezzo-Ambiesta dam in Northeastern Italy. B. Seismol. Soc. Am., 97(1B), 339-346.
Beresnev, I. A., Wen, K. L., and Yeh, Y. T. (1995). Nonlinear Soil Amplification - Its Corroboration In Taiwan. B. Seismol. Soc. Am., 85(2), 496-515.
Borcherdt, R. D. (1970). Effects Of Local Geology On Ground Motion Near San Francisco Bay. B. Seismol. Soc. Am., 60(1), 29-61.
Castro, R. R., Mucciarelli, M., Pacor, F., and Petrungaro, C. (1997). S-wave site-response estimates using horizontal-to-vertical spectral ratios. B. Seismol. Soc. Am., 87(1), 256-260.
Chen, K. H., Furumura, T., Rubinstein, J., and Rau, R.-J. (2011). Observations of changes in waveform character induced by the 1999 M(w)7.6 Chi-Chi earthquake. Geophys. Res. Lett., 38. doi: 10.1029/2011gl049841
Chen, K. C., Wang, J. H., Kim, K. H., and Leu, P. L. (2014). Strong Ground Motions Generated by the February 11, 2014 Tatunshan Earthquake in the Taipei Metropolitan Area. Terr. Atmos. Ocean. Sci., 25(5), 709-718. doi: 10.3319/tao.2014.05.27.01(t)
Chuang, S. Y., Chen H. C., Ching K. E., Rau R. J., and Hou C. S. (2008). Crustal Deformation in Central Taiwan Before and After the 1999 Chi-Chi Earthquake from GPS Observations, 1996-2006. Special Publication of the Central Geological Survey, 20, 63-80.
Cornou, C., Bard, P. Y., and Dietrich, M. (2003). Contribution of dense array analysis to the identification and quantification of basin-edge-induced waves, part II: Application to Grenoble basin (French Alps). B. Seismol. Soc. Am., 93(6), 2624-2648. doi: 10.1785/0120020140
Dilley, M. (2005). Natural disaster hotspots: A global risk analysis (Vol. 5): World Bank Publications.
Field, E., and Jacob, K. (1993). The Theoretical Response Of Sedimentary Layers To Ambient Seismic Noise. Geophys. Res. Lett., 20(24), 2925-2928. doi: 10.1029/93gl03054
Fletcher, J. B., and Wen, K. L. (2005). Strong ground motion in the Taipei basin from the 1999 Chi-Chi, Taiwan, earthquake. B. Seismol. Soc. Am., 95(4), 1428-1446. doi: 10.1785/0120040022
Gallipoli, M. R., and Mucciarelli, M. (2009). Comparison of Site Classification from VS30, VS10, and HVSR in Italy. B. Seismol. Soc. Am., 99(1), 340-351. doi: 10.1785/0120080083
Gosar, A. (2007). Microtrernor HVSR study for assessing site effects in the Bovec basin (NW Slovenia) related to 1998 M,5.6 and 2004 Mw5.2 earthquakes. Eng. Geol., 91(2-4), 178-193. doi: 10.1016/j.enggeo.2007.01.008
Huang, H. C. (2002). Characteristics of earthquake ground motions and the H/V of microtremors in the southwestern part of Taiwan. Earthq. Eng. Struct. D., 31(10), 1815-1829. doi: 10.1002/eqe.191
Huang, H. C., and Teng, T. L. (1999). An evaluation on H/V ratio vs. spectral ratio for site-response estimation using the 1994 Northridge earthquake sequences. Pure. Appl. Geophys., 156(4), 631-649. doi: 10.1007/s000240050316
Huang, M. W., Wang, J. H., Hsieh, H. H., and Wen, K. L. (2009). High frequency site amplification evaluated from Borehole data in the Taipei Basin. J. seismol., 13(4), 601-611. doi: 10.1007/s10950-009-9153-3
Huang, Yu-Chih. (2003). Site Effect and Near Surface S Wave Velocity Structure in Lan-Yang Plain. Master Thesis, National Central University, Taoyuan County.
Hudson, M., Idriss, I. M, and Beikae, M. (1994). A computer program to evaluate the seismic response of soil structures using finite element procedures and incorporating a compliant base. Center for Geotechnical Modeling, Department of Civil and Environmental Engineering(University of California Davis), Davis California.
Kohler, A., Ohrnberger, M., Scherbaum, F., Stange, S., and Kind, F. (2004). Ambient vibration measurements in the Southern Rhine Graben close to Basle. Ann. Geophys-Italy, 47(6), 1771-1781.
Kramer, S. L. (1996). Geotechnical Earthquake Engineering. Prentice Hall, New Jersey.
LeBrun, B., Hatzfeld, D., and Bard, P. Y. (2001). Site effect study in urban area: Experimental results in Grenoble (France). Pure. Appl. Geophys., 158(12), 2543-2557. doi: 10.1007/pl00001185
Lee, C. T., Cheng, C. T., Liao, C. W., and Tsai, Y. B. (2001). Site classification of Taiwan free-field strong-motion stations. B. Seismol. Soc. Am., 91(5), 1283-1297.
Lee, M. K. W., and Finn, W. D. L. (1978). DESDRA-2 Dynamic effective stress response analysis of soil deposits with energy transmitting boundary including assessment of liquefaction potential. Soil Mechanics Series n. 38, University of British Colombia(Vancouver).
Lee, S. J., Ma, K. F., and Chen, H. W. (2006a). Three-dimensional dense strong motion waveform inversion for the rupture process of the 1999 Chi-Chi, Taiwan, earthquake. J. Geophys. Res.-Sol. Ea., 111(B11), B11308. doi: 10.1029/2005JB004097
Lee, S.-J., Ma, K.-F., and Chen, H.-W. (2006b). Three-dimensional dense strong motion waveform inversion for the rupture process of the 1999 Chi-Chi, Taiwan, earthquake. J. Geophys. Res.-Sol. Ea., 111(B11). doi: 10.1029/2005jb004097
Lermo, J., and Chavez-Garcia, F. J. (1993). Site effect evaluation using spectral ratios with only one station. B. Seismol. Soc. Am., 83(5), 1574-1594.
Lin, Che-Min. (2009). Shallow velocity structure, site effect and 3D seismic wave simulation of the western plain of Taiwan. PhD Thesis, National Central University, Taoyuan County.
Lin, K. C., Hu, J. C., Ching, K. E., Angelier, J., Rau, R. J., Yu, S. B., and Huang, M. H. (2010). GPS crustal deformation, strain rate, and seismic activity after the 1999 Chi-Chi earthquake in Taiwan. J. Geophys. Res.-Sol. Ea., 115. doi: 10.1029/2009jb006417
Lombardo, G., and Rigano, R. (2006). Amplification of ground motion in fault and fracture zones: Observations from the Tremestieri fault, Mt. Etna (Italy). J. Volcanol. Geoth. Res., 153(3-4), 167-176. doi: 10.1016/j.jvolgeores.2005.10.014
Lombardo, G., and Rigano, R. (2007). Local seismic response in Catania (Italy): A test area in the northern part of the town. Eng. Geol., 94(1-2), 38-49. doi: 10.1016/j.enggeo.2007.06.008
Mak, S., Chan, L. S., Chandler, A. M., and Koo, R. C. H. (2004). Coda Q estimates in the Hong Kong region. J. Asian. Earth. Sci., 24(1), 127-136. doi: 10.1016/j.jseaes.2003.10.001
Meslem, A., Yamazaki, F., Maruyama, Y., Benouar, D., Laouami, N., and Benkaci, N. (2010). Site-Response Characteristics Evaluated from Strong Motion Records of the 2003 Boumerdes, Algeria, Earthquake. Earthq. Spectra., 26(3), 803-823. doi: 10.1193/1.3459158
Mittal, H., Kumar, A., and Kumar, A. (2013). Site Effects Estimation in Delhi from the Indian Strong Motion Instrumentation Network. Seismol. Res. Lett., 84(1), 33-41. doi: 10.1785/0220120058
Moisidi, M., Vallianatos, F., Soupios, P., and Kershaw, S. (2012). Spatial spectral variations of microtremors and electrical resistivity tomography surveys for fault determination in southwestern Crete, Greece. J. Geophys. Eng., 9(3), 261-270. doi: 10.1088/1742-2132/9/3/261
Moisidi, M., Vallianatos, F., Soupios, P., Kershaw, S., Rust, D., and Piscitelli, S. (2013). Modelling tectonic features of the Kissamos and Paleohora areas, Western Crete (Greece): combining geological and geophysical surveys. J. Geophys. Eng., 10(2). doi: 10.1088/1742-2132/10/2/025015
Nakamura, Y. (1989). A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface. Railway Technical Research Institute, Quarterly Reports, 30(1).
Panzera, F., Lombardo, G., D’Amico, S., and Galea, P. (2013). Speedy techniques to evaluate seismic site effects in particular geomorphologic conditions: faults, cavities, landslides and topographic irregularities. In S. D'Amico (Ed.), Engineering Seismology, Geotechnical and Structural Earthquake Engineering.
Parolai, S., Orunbaev, S., Bindi, D., Strollo, A., Usupaev, S., Picozzi, M., . . . Zschau, J. (2010). Site Effects Assessment in Bishkek (Kyrgyzstan) Using Earthquake and Noise Recording Data. B. Seismol. Soc. Am., 100(6), 3068-3082. doi: 10.1785/0120100044
Puglia, R., Ditommaso, R., Pacor, F., Mucciarelli, M., Luzi, L., and Bianca, M. (2011). Frequency variation in site response as observed from strong motion data of the L'Aquila (2009) seismic sequence. B. Earthq. Eng., 9(3), 869-892. doi: 10.1007/s10518-011-9266-2
Rautian, T. G., and Khalturin, V. I. (1978). USE OF CODA FOR DETERMINATION OF EARTHQUAKE SOURCE SPECTRUM. B. Seismol. Soc. Am., 68(4), 923-948.
Rubinstein, J. L., Uchida, N., and Beroza, G. C. (2007). Seismic velocity reductions caused by the 2003 Tokachi-Oki earthquake. J. Geophys. Res.-Sol. Ea., 112(B5). doi: 10.1029/2006jb004440
Sawazaki, K., Sato, H., Nakahara, H., and Nishimura, T. (2009). Time-Lapse Changes of Seismic Velocity in the Shallow Ground Caused by Strong Ground Motion Shock of the 2000 Western-Tottori Earthquake, Japan, as Revealed from Coda Deconvolution Analysis. B. Seismol. Soc. Am., 99(1), 352-366. doi: 10.1785/0120080058
Schnabel, B., Lysmer, J, and Seed, H. (1972). SHAKE: a computer program for earthquake response analysis of horizontally layered sites. Rep. E.E.R.C. 7212Earthq. Eng. Research Center, Univ. Califormia(Berkeley).
Sgarlato, G., Lombardo, G., and Rigano, R. (2011). Evaluation of seismic site response nearby underground cavities using earthquake and ambient noise recordings: A case study in Catania area, Italy. Eng. Geol., 122(3-4), 281-291. doi: 10.1016/j.enggeo.2011.06.002
Shih, Ta. (2006). Consult the site effect of I-LAN. Master Thesis, National Chung Cheng University, Chiayi County.
Sokolov, V. Y., Loh, C.-H., and Jean, W.-Y. (2007). Application of horizontal-to-vertical (H/V) Fourier spectral ratio for analysis of site effect on rock (NEHRP-class B) sites in Taiwan. Soil. Dyn. Earthq. Eng., 27(4), 314-323. doi: 10.1016/j.soildyn.2006.09.001
Song, G. C., and Lin, W. H. (1993). Fangliao Geological Maps and Instructions: 1/50000 Geological Maps No. 67, Central Geological Survey, MOEA.
Steidl, J. H., Tumarkin, A. G., and Archuleta, R. J. (1996). What is a reference site? B. Seismol. Soc. Am., 86(6), 1733-1748.
Strollo, A., Richwalski, S. M., Parolai, S., Gallipoli, M. R., Mucciarelli, M., and Caputo, R. (2007). Site effects of the 2002 Molise earthquake, Italy: analysis of strong motion, ambient noise, and synthetic data from 2D modelling in San Giuliano di Puglia. B. Earthq. Eng., 5(3), 347-362. doi: 10.1007/s10518-007-9033-6
TevesCosta, P., Matias, L., and Bard, P. Y. (1996). Seismic behaviour estimation of thin alluvium layers using microtremor recordings. Soil. Dyn. Earthq. Eng., 15(3), 201-209. doi: 10.1016/0267-7261(95)00038-0
Tsuda, K., Koketsu, K., Hisada, Y., and Hayakawa, T. (2010). Inversion Analysis of Site Responses in the Kanto Basin Using Data from a Dense Strong Motion Seismograph Array. B. Seismol. Soc. Am., 100(3), 1276-1287. doi: 10.1785/0120090153
Tu C. S. (2005). Using microtremor measurement to study the site effect in the central Taiwan. Master Thesis, National Central University, Taoyuan County.
Wen, K. L., and Peng, H. Y. (1998). Site effect analysis in the Taipei basin: Results from TSMIP network data. Terr. Atmos. Ocean. Sci., 9(4), 691-704.
Wen, K. L., Yeh, Y. T., and Huang, W. G. (1992). EFFECTS OF AN ALLUVIAL BASIN ON STRONG GROUND MOTIONS. B. Seismol. Soc. Am., 82(2), 1124-1133.
Wood, H. O. (1908). Distribution of apparent intensity in San Francisco, in the California earthquake of April 18, 1906. Report of the State Earthquake Investigation Commission, Canergie Institute of Washington(Washington, D.C.), 1.
Wu, C., and Peng, Z. (2011). Temporal changes of site response during the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake. Earth. Plants. Space., 63(7), 791-795.
Wu, C., Peng, Z., and Ben-Zion, Y. (2009). Non-linearity and temporal changes of fault zone site response associated with strong ground motion. Geophys. J. Int., 176(1), 265-278. doi: 10.1111/j.1365-246X.2008.04005.x
Wu, C. S., Yu, T. T., and Peng, W. F. (2013). Analysis of site response variation resulting from fault movement: Observations from the Chelungpu fault in Taiwan. Paper presented at the EGU General Assembly Conference Abstracts.
Yeh, J. T. (2001). Analysis of Nonlinear Soil Response During the Chi-chi Earthquake Using Horizontal-to-Vertical Spectral Ratio Method. National Central University.
Yu, S. B., Kuo, L. C., Hsu, Y. J., Su, H. H., Liu, C. C., Hou, C. S., and Shin, T. C. (2001). Preseismic deformation and coseismic displacements associated with the 1999 Chi-Chi, Taiwan, earthquake. B. Seismol. Soc. Am., 91(5), 995-1012.