台灣位處於板塊聚合帶，地震活動頻繁，其中花東縱谷位在菲律賓海板塊與歐亞板塊的碰撞縫合帶，在聚合的過程中產生兩條近似平行的斷層系統，一條是沿著縱谷西側高角度向西傾的中央山脈斷層，另一條則是沿著縱谷東側向東傾的縱谷斷層。池上斷層位於縱谷南段，是屬於相當活躍的逆衝潛移斷層，根據大地測量結果，其每年平均向西北滑移2~3公分，在歷史上也發生過兩起規模六以上的大規模地震，分別為1951年的花東地震序列及2003年的成功地震。
　　本研究藉由層析成像反演縱谷南段，來探討2003年成功地震前後速度構造的時空變化。利用最小阻尼法及3D波線追跡法計算出最佳解，以獲得地下速度構造，初步結果顯示，Vp的變化量比Vs和Vp/Vs比值更小，且Vs構造在成功地震主震過後表現出更明顯的速度變化，表示在主震前池上斷層的Vp/Vs比值開始增加，可能與裂隙密度變化及液體增加有關。在前人的研究中指出，高Vp/Vs比值可能和裂隙的生成及液體的侵入有關，裂隙增加會改變岩石體積並使液體侵入產生部分補償。
　　本研究不僅可以了解台灣東南部的孕震構造，更可以觀察強震序列中地下裂隙增生所引起的物理變化。藉由縱谷南段Vp/Vs比值的時空變化結果，可以評估該地區的地震危害性，並進一步探討斷層的地震活動與流變性的關係。未來若長期監測可應用於大規模地震預警研究。

　　Taiwan is located in the plate converge zone, in which the Longitudinal Valley(LV) is the suture zone between the Eurasian Plate and Philippine Sea Plate. The collision process yields two nearly parallel major fault systems: the Central Range fault (CRF) and the Longitudinal Valley fault(LVF). The Chihshang fault is a creeping thrust fault, which is located in the southern section of the LVF in eastern Taiwan. According to geodetic survey, this fault moves to northwest at a rate approximately 2–3 cm/yr. There were two significant earthquakes occurred nearby the Chihshang fault, the 1951 M7.1 Hualien-Taitung earthquake and the 2003 M6.4 Chengkung earthquake.
　　In this study, the spatial and temporal variations of velocity structure before and after 2003 Chengkung earthquake were obtained through the tomography inversion beneath the southern segment of the Longitudinal Valley. The damping least-square technique and 3D ray tracing scheme were adopted to calculate the most appropriate solution and obtain the velocity structures. The results showed that the Vp values exhibit less significant variations than the parameters Vs and Vp/Vs ratio. But the Vs structures show larger variation after the 2003 mainshock. These results imply that Vp/Vs ratios began to increase before the mainshock, at the hanging wall of the Chihshang fault, which may be related to the increasing density of microcracks and fluid. Previous studies has shown that high Vp/Vs ratio may lead to cracks generating and fluid migration, which can result in changing rock volume and produce partial compensation. Therefore, our results not only give better understanding the seismogenic structures in the ES Taiwan, but also allow us to detect variations of physical parameters caused by crack propagating in stratum during the strong earthquake sequence. Hence, this study shows that the results from temporal and spatial variation of Vp/Vs values in the southern segment of the LVF could allow us to assess the seismic hazard potential in this area, and further explore the relationship between the seismicity and the rheology of fault plane. Finally, long-term monitoring of fault activities will contribute to the research of future earthquake early warning.

致謝 I
中文摘要 III
Abstract V
目錄 VII
圖目錄 IX
表目錄 XIII
第 1 章 緒論 2
1-1 研究動機與目的 2
1-2 研究區域簡介 4
1-3 文獻回顧 8
第 2 章 研究方法 14
2-1 近似波線追蹤法 16
2-2 走時逆推 17
2-3 解析度矩陣(Resolution) 20
2-4 標準差(Standard Deviation) 20
2-5 導數加權總合(Derivative Weight Sum,DWS) 20
第 3 章 資料處理與初始模型檢驗 22
3-1 資料選取與處理 26
3-2 初始速度構造模型 27
3-3 初始模型格點 27
3-4 模型檢驗 28
3-4-1 棋盤格檢驗(Checkerboard text) 28
3-4-2 導數加權總合(Derivative Weight Sum，DWS) 32
3-4-3 標準差(Standard Deviation) 36
第 4 章 結果與討論 40
4-1 重定位結果 43
4-2 速度構造反演結果 47
4-3 速度剖面分析 54
4-4 中大型地震前後時空變化 67
第 5 章 結論 76
第 6 章 參考文獻 78
第 7 章 附錄 86
7-1 附錄一 86
7-2 附錄二 91
7-3 附錄三 93

Angelier, J., Chu, H.T., Lee, J.C., Hu, J.C.,( 2000). Active faulting and earthquake hazard: the case study of continuous monitoring of the Chihshang Fault, Taiwan. J. Geodyn. 29, 151–185.
Backus, G., & Gilbert, F. (1968). The resolving power of gross earth data. Geophysical Journal International, 16(2), 169-205.
Bürgmann, R., Schmidt, D., Nadeau, R. M., d'Alessio, M., Fielding, E., Manaker, D., ... & Murray, M. H. (2000). Earthquake potential along the northern Hayward fault, California. Science, 289(5482), 1178-1182.
Chen, W. S., & Wang, Y. (1988). Development of deep-sea fan systems in Coastal Range basin, eastern Taiwan. Acta Geologica Taiwanica, 26, 36-56.
Chen, H. H., and R. J. Rau, 2002: Earthquake Locations and Focal Mechanisms in an Active Arc-Continent Plate Boundary: the Chihshang Fault of Eastern Taiwan, EOS Trans. AGU, 83, Fall Meet. Suppl., Abs. T61-1277.
Chen, H.‐Y., S.‐B. Yu, L.‐C. Kuo, and C.‐C. Liu (2006), Coseismic and postseismic displacement of the 10 December 2003 (Mw 6.5) Chengkung earthquake, eastern Taiwan, Earth Planets Space, 58, 5– 21.
Ching, K. E., Rau, R. J., & Zeng, Y. (2007). Coseismic source model of the 2003 Mw 6.8 Chengkung earthquake, Taiwan, determined from GPS measurements. Journal of Geophysical Research: Solid Earth, 112(B6).
Chen, K. H., Nadeau, R. M., & Rau, R. J. (2008). Characteristic repeating earthquakes in an arc-continent collision boundary zone: The Chihshang fault of eastern Taiwan. Earth and Planetary Science Letters, 276(3-4), 262-272.
Christensen, N. I., & Mooney, W. D. (1995). Seismic velocity structure and composition of the continental crust: A global view. Journal of Geophysical Research: Solid Earth, 100(B6), 9761-9788.
Christensen, N. I. (1996). Poisson's ratio and crustal seismology. Journal of Geophysical Research: Solid Earth, 101(B2), 3139-3156.
Chuang, R. Y., Johnson, K. M., Kuo, Y. T., Wu, Y. M., Chang, C. H., & Kuo, L. C. (2014). Active back thrust in the eastern Taiwan suture revealed by the 2013 Rueisuei earthquake: Evidence for a doubly vergent orogenic wedge?. Geophysical Research Letters, 41(10), 3464-3470.
Domenico, S. N. (1984). Rock lithology and porosity determination from shear and compressional wave velocity. Geophysics, 49(8), 1188-1195.
Eastwood, R. L., & Castagna, J. P. (1983, January). Basis for interpretation of Vp/Vs ratios in complex lithologies. In SPWLA 24th Annual Logging Symposium. Society of Petrophysicists and Well-Log Analysts.
Eberhart‐Phillips, D. (1990). Three‐dimensional P and S velocity structure in the Coalinga region, California. Journal of Geophysical Research: Solid Earth, 95(B10), 15343-15363.
Hsu, T. L. (1962). Recent faulting in the Longitudinal Valley of eastern Taiwan. Proc. Geol. Soc. China Mem., 1, 95-102.
Ho, C. S. (1982). Tectonic evolution of Taiwan: explanatory text of the tectonic map of Taiwan (p. 126). Ministry of Economic Affairs, Republic of China.
Hu, J. C., Cheng, L. W., Chen, H. Y., Wu, Y. M., Lee, J. C., Chen, Y. G., ... & Yu, S. B. (2007). Coseismic deformation revealed by inversion of strong motion and GPS data: the 2003 Chengkung earthquake in eastern Taiwan. Geophysical Journal International, 169(2), 667-674.
Huang, H. H., Wu, Y. M., Song, X., Chang, C. H., Lee, S. J., Chang, T. M., & Hsieh, H. H. (2014). Joint Vp and Vs tomography of Taiwan: Implications for subduction-collision orogeny. Earth and Planetary Science Letters, 392, 177-191.
Kern, H. (1981). Temperature derivatives of compressional and shear wave velocities in crustal and mantle rocks at 6 kbar confining pressure. J. Geophys., 49, 47-56.
Kim, K. H., Chen, K. C., & Chiu, J. M. (2013). Three-dimensional structure of V p, V s and V p/V s beneath the active collision boundary of eastern Taiwan. Geophysical Journal International, 196(1), 78-95.
Kithas, B. A. (1976, January). Lithology, gas detection, and rock properties from acoustic logging systems. In SPWLA 17th Annual Logging Symposium. Society of Petrophysicists and Well-Log Analysts.
Kuochen, H., Wu, Y. M., Chang, C. H., Hu, J. C., and Chen, W. S. (2004) Relocation of the eastern Taiwan earthquakes and its tectonic implications, Terr. Atmos. Oceanic., 15, 647-666.
Kuochen, H., Wu, Y. M., Chen, Y. G., & Chen, R. Y. (2007). 2003 Mw6. 8 Chengkung earthquake and its related seismogenic structures. Journal of Asian Earth Sciences, 31(3), 332-339.
KuoChen, H., Wu, F. T., Jenkins, D. M., Mechie, J., Roecker, S. W., Wang, C. Y., & Huang, B. S. (2012a). Seismic evidence for the α‐β quartz transition beneath Taiwan from Vp/Vs tomography. Geophysical Research Letters, 39(22).
KuoChen, H., Wu, F. T., & Roecker, S. W. (2012b). Three‐dimensional P velocity structures of the lithosphere beneath Taiwan from the analysis of TAIGER and related seismic data sets. Journal of Geophysical Research: Solid Earth, 117(B6).
Lee, J. C., Angelier, J., Chu, H. T., Hu, J. C., & Jeng, F. S. (2001). Continuous monitoring of an active fault in a plate suture zone: a creepmeter study of the Chihshang Fault, eastern Taiwan. Tectonophysics, 333(1-2), 219-240.
Lee, J. C., Angelier, J., Chu, H. T., Hu, J. C., Jeng, F. S., and Rau, R. J. (2003) Active fault creep variations at Chihshang, Taiwan, revealed by creep meter monitoring, 1998-2001, Journal of Geophysical Research, 108, B11, 2528.
Lee, J. C., Chu, H. T., Angelier, J., Hu, J. C., Chen, H. Y., & Yu, S. B. (2006). Quantitative analysis of surface coseismic faulting and postseismic creep accompanying the 2003, Mw= 6.5, Chengkung earthquake in eastern Taiwan. Journal of Geophysical Research: Solid Earth, 111(B2).
Lin, J. Y., Hsu, S. K., Lin, A. T. S., Yeh, Y. C., & Lo, C. L. (2016). Vp/Vs distribution in the northern Taiwan area: Implications for the tectonic structures and rock property variations. Tectonophysics, 692, 181-190.
Matsubara, M., Yagi, Y., & Obara, K. (2005). Plate boundary slip associated with the 2003 Off‐Tokachi earthquake based on small repeating earthquake data. Geophysical Research Letters, 32(8).
Miller, S. L., & Stewart, R. R. (1990). Effects of lithology, porosity and shaliness on P-and S-wave velocities from sonic logs. Canadian Journal of Exploration Geophysics, 26(1-2), 94-103.
Mozziconacci, L., Delouis, B., Angelier, J., Hu, J. C., & Huang, B. S. (2009). Slip distribution on a thrust fault at a plate boundary: The 2003 Chengkung earthquake, Taiwan. Geophysical Journal International, 177(2), 609-623.Nations, J. F. (1974). Lithology and porosity from acoustic shear and compressional wave transit time relationships. The Log Analyst, 15(06).
Nadeau, R. M., & McEvilly, T. V. (1999). Fault slip rates at depth from recurrence intervals of repeating microearthquakes. Science, 285(5428), 718-721.
O'Connell, R. J., & Budiansky, B. (1974). Seismic velocities in dry and saturated cracked solids. Journal of Geophysical Research, 79(35), 5412-5426.
O'Connell, R. J., & Budiansky, B. (1977). Viscoelastic properties of fluid‐saturated cracked solids. Journal of Geophysical Research, 82(36), 5719-5735.
Pavlis, G. L., & Booker, J. R. (1980). The mixed discrete‐continuous inverse problem: Application to the simultaneous determination of earthquake hypocenters and velocity structure. Journal of Geophysical Research: Solid Earth, 85(B9), 4801-4810.
Shyu, J. B. H., Sieh, K., Avouac, J. P., Chen, W. S., & Chen, Y. G. (2006). Millennial slip rate of the Longitudinal Valley fault from river terraces: Implications for convergence across the active suture of eastern Taiwan. Journal of Geophysical Research: Solid Earth, 111(B8).
Tadokoro, K., & Ando, M. (2002). Evidence for rapid fault healing derived from temporal changes in S wave splitting. Geophysical Research Letters, 29(4), 6-1.
Takei, Y. (2002). Effect of pore geometry on Vp/Vs: From equilibrium geometry to crack. Journal of Geophysical Research: Solid Earth, 107(B2), ECV-6.
Thurber, C. H. (1983). Earthquake locations and three‐dimensional crustal structure in the Coyote Lake area, central California. Journal of Geophysical Research: Solid Earth, 88(B10), 8226-8236.
Thurber, C.H., 1993. Local earthquake tomography: velocities and Vp/Vs –theory, Seismic tomography; theory and practice, Chapman and Hall ;London, 563-583.
Toomey, D. R., & Foulger, G. R. (1989). Tomographic inversion of local earthquake data from the Hengill‐Grensdalur central volcano complex, Iceland. Journal of Geophysical Research: Solid Earth, 94(B12), 17497-17510.
Um, J., & Thurber, C. (1987). A fast algorithm for two-point seismic ray tracing. Bulletin of the Seismological Society of America, 77(3), 972-986.
Wen, Y. Y., Yen, Y. T., Wen Strong, Lee, S. J., Kuo, C. H., & Yen-Yu, L. (2016). Hybrid ground motion simulation for the 2013 M L 6.4 Ruisui, Taiwan earthquake. TAO: Terrestrial, Atmospheric and Oceanic Sciences, 27(3), 407.
Wiggins, R. A. (1972). The general linear inverse problem: Implication of surface waves and free oscillations for earth structure. Reviews of Geophysics, 10(1), 251-285.
Wu, Y. M., Chen, Y. G., Shin, T. C., Kuochen, H., Hou, C. S., Hu, J. C., ... & Teng, T. L. (2006). Coseismic versus interseismic ground deformations, fault rupture inversion and segmentation revealed by 2003 Mw 6.8 Chengkung earthquake in eastern Taiwan. Geophysical research letters, 33(2).
Wu, Y. M., Chang, C. H., Zhao, L., Shyu, J. B. H., Chen, Y. G., Sieh, K., & Avouac, J. P. (2007). Seismic tomography of Taiwan: Improved constraints from a dense network of strong motion stations. Journal of Geophysical Research: Solid Earth, 112(B8).
Wu, Y. M., Chang, C. H., Zhao, L., Teng, T. L., & Nakamura, M. (2008). A comprehensive relocation of earthquakes in Taiwan from 1991 to 2005. Bulletin of the Seismological Society of America, 98(3), 1471-1481.
Yu, S. B., and Liu, C. C. (1989) Fault creep on the central segment of the Longitudinal Valley Fault, eastern Taiwan, Proc. Geol. Soc. China, 32, 209-231.
Yu, S. B., Chen, H. Y., & Kuo, L. C. (1997). Velocity field of GPS stations in the Taiwan area. Tectonophysics, 274(1-3), 41-59.
Yu, S. B., & Kuo, L. C. (2001). Present-day crustal motion along the Longitudinal Valley Fault, eastern Taiwan. Tectonophysics, 333(1-2), 199-217.
交通部中央氣象局地震季報，第四十七卷，第二號，第1-9頁，2000。
畢慶昌 (1965) The East Taiwan Rift = 東臺灣裂谷。 Petroleum Geology of Taiwan=臺灣石油地質;第4號,第93-106頁
林啟文，陳文山，劉彥求，陳柏村 (2009)。台灣東部與南部的活動斷層，二萬五千分之一活動斷層條帶圖說明書。經濟部中央地質調查所特刊，第23期，1-178頁。
陳文山, 林益正, 顏一勤, 楊志成, 紀權窅, 黃能偉, ... & 林燕慧. (2008). 從古地震研究與 GPS 資料探討縱谷斷層的分段意義. 經濟部中央地質調查所特刊, (20), 165-191.
陳文山，吳逸民，葉柏逸，賴奕修，柯明淳，柯孝勳，林義凱 (2018) 台灣東部碰撞帶孕震構造。經濟部中央地質調查所特刊，第三十三號，第123-155頁。
徐鐵良 (1955）臺灣的地震。臺灣銀行季刊，第七期，第39-63頁 。
溫士忠 (2007)，高效率非線性波行反演程序研究---台北盆地震波速度構造推求之應用，國立中正大學博士論文。