本研究利用11座連續GPS追蹤站及地面三維雷射掃描於2004年11月至2005年3月監測台灣東部活動斷層（池上斷層）的同震及震後變形，並進一步了解斷層面滑移分佈與地表位移關係。藉由連續GPS追蹤站之時間序列觀測資料，建立觀測值之擬合曲線，來評估震後某一段時間之位移量。在同震及震後三個月中，池上斷層上盤的變形方向主要是朝向北方或東北方，而下盤的位移向量卻是朝東南方。然而，在地震三個月後，上盤及下盤的位移方向主要朝向西北方向，此與位移量已顯示逐漸恢復至震間期。從同震至震後，我們清楚觀察到地表位移向量隨時間改變。因此，使用彈性半無限空間模型逆推斷層面滑移分佈，結果顯示同震時斷層面滑移分佈主要位於斷層深處（15-25km）、震後三個月位於斷層淺層（0-10 km），接續震後一年位於斷層深處（25-40km）。震後三個月滑移模型計算所得之大地測量力矩和成功地震餘震的力矩分別為4.41 × 1026 dyne-cm（主震的二倍）及1.469 × 1024 dyne-cm，故震後能量大部份藉由震後滑移方式釋放。這顯示出成功地震的能量不僅由主震釋放外，也藉由震後滑移的形式逐漸釋放。因此，花東縱谷斷層的地表變形會受到中規模地震後快速改變。

　　從地面三維雷射掃描的結果顯示出近斷層的變形行為（大坡國小）。我們藉由大坡國小的二面擋土牆進行分析，第一面牆位於池上斷層上，另第三面牆位於斷層東側25公尺之坡地上。在地震後，第一面牆南端的變形向西變形7-8公分，而北端不明顯。第三面牆南端的變形不顯著，而北端卻向西變形7-8公分。十個月後，第一面牆的變形行為在地震後未有增加之趨勢，而第三面牆的變形行為卻與同震時期完全相反。此現象指示出近斷層在同震時除受到影響外，在震後期間仍持續受到影響而損壞。研究成果指示：台東成功地震之震後能量比主震大，並以無震滑移方式從斷層深部快速地釋放至花東縱谷斷層地表。

　We used continuous GPS observations and 3D ground-based laser scanner data in east Taiwan to monitor the activity of an active reverse fault – the Chihshang fault. It supplies an opportunity to realize the relationship between surface displacements and distribution of fault slips for a high-angle thrust fault system. Observations from 11 continuous GPS sites were utilized to discuss the co-seismic and post-seismic deformations of Chihshang fault associated with 2003 Mw 6.5 Chengkung earthquake in the period between November 2003 and March 2005. We attempt to explain post-seismic surface displacements by estimating best-fit curves for the GPS data. Orientations of displacements on the hanging wall of Chihshang fault directed toward north or northeast within 3 months after the main shock, whereas stations on the footwall moved toward southeast. However, displacement orientations on both hanging wall and footwall sides were directing toward northwest 3 months afterwards. Ratio of displacements between hanging wall and footwall of Chihshang fault were gradually recovered to the ratio in the interseismic period. We also estimated distribution of fault slips by inverting surface displacements using elastic half-space dislocation model. The result of this model presented here indicates that the main distribution of fault slip was located at depths of 15-25 km for co-seismic deformation. However, within three months after the main shock, fault slip was mainly placed at depths of 0-10 km and reached the surface. Three months after the main event, most of the slip became deeper and was located at depths of 25-40 km. The geodetic moment and aftershock moment calculated are about 4.41 × 1026 dyne-cm and 1.469 × 1024 dyne-cm, respectively. This indicates that energy of the Chengkung earthquake was not only released by the main shock, but also by the mostly aseismic afterslip. Therefore, the deformation changed quickly to the surface of Longitudinal Valley Fault within three months following the Chengkung earthquake.

　Results from the 3D ground-based laser scanner indicate co-seismic and post-seismic deformations of two retaining walls in Tapo elementary school, the vicinity of Chihshang fault zone. One is the first wall, which located on the Chihshang fault, and the other is the third wall, which was built far away 25 m from the fault trace. After the main shock, deformation of southern part of the first wall moved toward west about 7-8 cm, but the deformation for the northern part is not apparent. Deformation of the southern part of the third wall is not apparent and the deformation of northern part shifted toward west about 7-8 cm. Within ten months after the earthquake, deformation of the first wall was minimal after the main shock, but deformation of third wall is significantly different from that of the co-seismic deformation. These phenomena indicate structure in near fault was not only affected by the main shock, but also by post-seismic energy. This study concludes the post-seismic energy of Chengkung earthquake is large than co-seismic energy, and this energy released rapidly from depth of 15-25 km to the surface of Chihshang fault by afterslip.

Altamimi Z., Sillard P., and Boucher C., ITRF2000: A new release of the International Terrestrial Reference Frame for earth science applications, J. geophys. res., 107, B10, 2214, 2002
Angelier, J., H. T. Chu, J. C. Lee, Shear concentration in a collision zone: kinematics of the Chihshang Fault as revealed by outcrop-scale quantification of active faulting, Longitudinal Valley, eastern Taiwan, Tectonophysics, 274, 117-143, 1997.
Angelier, J., H. T. Chu, J. C. Lee, J. C. Hu, Active faulting and earthquake hazard: The case study of the Chihshang Fault, Taiwan. J. Geodyn., 29, 151-185, 2000.
Aoki Y. and C. H. Scholz, Vertical deformation of the Japanese island, 1996-1999, J. Geophys. Res., 108, B5, 2257, 2003.
Behan, A., On the matching accuracy of rasterised scanning laser altimeter data, IAPRS, 33, B2, 75-82, 2000.
Boehler, W., A. Marbs, 3D scanning instruments, CIPA, Heritage Documentation - International Workshop on Scanning for Cultural Heritage Recording - Corfu, Greece, 2002.
Boehler, W., G.. Heinz, A. Marbs, The potential of non-contact close range laser scanners for cultural heritage recording, Proceedings of CIPA International Symposium, Potsdam, Germany, 2001.
Ching, K. E., R. J. Rau, and Y. Zeng, Coseismic source model of the 2003 Cheng-Kung, Taiwan, earthquake based on the GPS displacement observations, the tenth Taiwan Symposium of Geophysics, 2004.
Dammert, P. B. G., Accuracy of INSAR Measurements in Forested Areas, ESA workshop on Applications of ERS SAR Interferometry （30 Septerber to 2 October 1996）, 1996, http://www.geo.unizh.ch/rsl/fringe96/papers/dammert/
Deng J., M. Gurnis, H. Kanamori, E. Hauksson, Viscoelastic flow in the lower crust after the 1992 Landers, California, earthquake, Science, 282, 27, 1998.
Donnellan, A., and G.. A. Lyzenga, GPS observation of fault afterslip and upper crustal deformation following the Northidge earthquake, J. Geophys. Res., 103, 21285-21297, 1998.
Hearn, E. H., What can GPS data tell us about the dynamics of post-seismic deformation, Geophys. J. Int., 154,1-25, 2003.
Heki, K., Dense GPS array as a new sensor of seasonal changes of surface loads, in The State of the Planet: Frontiers and Challenges in Geophysics, edited by R.S.J. Sparks and C.J. Hawkesworth, Geophys. Monograph, 150, 177-196, American Geophysical Union, Washington, 2004.
Hsu, Y. J., N. Bechor, P. Segall, S. B. Yu, L. C. Kuo, and K. F. Ma, Rapid afterslip following the 1999 Chi-Chi, Taiwan Earthquake, Geophys. Res. Lett., 29, 16, 1-4, 2002.
Hsu, Y. T., and C. C. Fu, Seismic effect on highway bridges in Chi Chi earthquake, ASCE, 18, 1, 47-53, 2004.
Huang, C. C., and Y. H. Chen, Seismic stability of soil retaining walls situated on slope, ASCE, 130, 1, 45-57, 2004.
Kumar, K. V., K. Miyashita, and J. Li, Secular crustal deformation in central Japan, based on the wavelet analysis of GPS time-series data, Earth Planets Space, 54, 133-139, 2002.
Lee, J.C. and J. Angelier, Localisation des déformations actives et traitements des données géodésiques: l'example de la faille de la Vallée Longitudinal, Taïwan. Bull. Soc. Géol. France, 164, 4, pp. 533-540, 1993.
Lee, J. C., J. Angelier, H. T. Chu, J. C. Hu, F. S. Jeng, and R. J. Rau, Active fault creep variations at Chihshang, Taiwan, revealed by creepmeter monitoring, 1998-2001, J. Geophys. Res., 108, B11, 2528, 2003.
Lee, J. C., J. Angelier, H. T. Chu, J. C. Hu, and F. S. Jeng, Continuous monitoring of an active fault in a plate suture zone: a creepmeter study of the Chihshang active fault, eastern Taiwan, Tectonophysics, 333, 219-240, 2001.
Marone, C. J., C. H. Scholtz, and R. Bilham, On the mechanics of earthquake afterslip., J. Geophys. Res., 96, 8441-8452, 1991.
Milliken, R. J. and Zoller, C. J., Principle of Operation of NAVSTAR and System Characteristics, NAVIGATION, Volume I, 1980.
Nikolaidis, R., Observation of geodetic and seismic deformation with the Global Position System, Ph.D. dissertation, Univ. of Calif. San Diego, 2002.
Optech, http://ilris-3d.com, 2002.
POB, Point of Beginning, http://www.pobonline.com, 2004.
Pollitz, F. F., Transient rheology of the uppermost mantle beneath the Mojave Desert, California, Earth Planet. Sci. Lett., 215, 89-104, 2003.
Segall, P., Integrating geologic and geodetic estimates of slip rate on the San Andreas fault system, Int. Geol. Rev., 44, 62-82, 2002.
Shaw, J., and P. Shearer, An elusive blind-thrust fault beneath metropolitan Los Angeles: Science, 283, 1516-1518, 1999.
Skinner B. J., S. C. Porter, J. Park, Dynamic earth: An introduction to physical geology fifth edith, New York, John Wiley and sons, 230-232, 2004.
Thatcher, W., and J. B. Rundle, A viscoelastic coupling model for the cyclic deformation due to periodically repeated earthquakes at subduction zones, J. Geophys. Res., 89, 7631-7640, 1984.
Thomas, A. L., POLY3D: A three-dimensional, polygonal element, displacement discontinuity boundary element computer program with applications to fractures, faults, and cavities in the earth's crust, master thesis, 1993.
Unruh, J. R. and R. J. Twiss, Coseismic growth of basement-involved anticlines: The Northridge-Laramide connection, Geology, 26, 4, 335-338, 1998.
Yu, S. B., and C. C. Liu, Fault creep on the central segment of the longitudinal valley fault, Eastern Taiwan, Proc. Geol. Soc. China, 32, 3, 209-231, 1989.
Yu, S. B., and L. C. Kuo, Present-day crustal motion along the Longitudinal Valley Fault, eastern Taiwan, Tectonophysics, 333, 199-217, 2001.
Yu, S.B., H. Y. Chen, and L. C. Kuo, Velocity field of GPS stations in the Taiwan area, Tectonophysics, 274, 41-59, 1997.
何維信，測量學，第二版，宏泰出版社，1996.
吳秉輯、黃偉城、饒瑞鈞、曾清凉、詹瑜璋、李建成，地面三維雷射掃描觀測人工建物於近斷層的同震及震後變形，第六屆GPS衛星科技研討會，2004。
李建成、朱傚祖、安朔葉、胡植慶、余水倍、陳宏宇、鄭富書、林正洪、饒瑞鈞、周錦德、張勝雄、姜國彰，從地殼變形與斷層活動討論地震災害潛在性：花東縱谷池上活斷層的研究，地質，21卷，第二期，31-52，2002。
李建成、朱傚祖、安朔葉、胡植慶，台灣東部縱谷斷層的快速潛移特性及地震災害，2004年台灣活動斷層與地震災害研討會論文集，11-18，2004。
周光泉、劉孝敏編著，黏彈性理論，中國科學技術大學出版社，合肥，3-45，1996。
郭朗哲、史天元，地面光達資料疊合之研究-以竹東崩塌地為例，第二十三屆測量學術及應用研討會，323-332，2004。
陳卉瑄，差分合成孔鏡干涉雷達應用於偵測集集地震地形變化之研究，國立成功大學地球科學研究所碩士論文，50-59，2001。
曾清凉、儲慶美，GPS衛星測量原理與應用，第二版，國立成功大學衛星資訊研究中心，1-12，1999。
曾義星、史天元，2004。三維雷射掃瞄技術及其在工程測量上之應用，土木水利，已接受。
黃偉城，利用地面三為雷射掃描儀研究斷層變形知可行性-2003年Mw6.5台東成功地震池上斷層知同震及震後研究，國立成功大學地球科學研究所碩士論文，43-58，2004。
詹瑜璋、陳于高、史天元，利用空載雷射掃描資料分析新城斷層系統：清晰之地形與其代表之構造作用，中國地質學會九十二年年會手冊及論文集，133，2003。