航空攝影測量技術於近斷層之地表變形觀測:以台灣東部池上地區為例
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2014
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1990年以來，國內外學者在東部地區建立一系統板塊邊界監測的研究，利用現地量測、大地測量及地震學方法監測斷層活動性，以確實掌握區域內地震活動與地表變形等。2003年12月10日規模6.3的成功地震，成為了解池上斷層震前、同震及震後活動特性的關鍵。有鑑於目前近斷層監測的方式仍需要投入大量的人力與物力資源，本研究利用航空影像大範圍、大面積的優勢，針對2003年成功地震前後產製共7個時期的航空正射影像，透過固定剖面長度的變化，進行跨斷層之地表變形量分析。
本研究為了提高空三測量的精度，透過GPS-RTK現地量測共14 個控制點，其平均誤差值約 0.0149公尺。透過三維空三校正的結果，發現池上斷層於成功地震前南段及北段呈現拉張，而中段為擠壓狀態；震後四個月之資料顯示南、北段為擠壓狀態，但中段的拉張區域範圍變小；而2004年9月全區呈現擠壓狀態；2005年則北段及南段仍呈現擠壓，中段則轉為拉張狀態；2006年中段拉張則範圍則為由南北兩端擴大；2007年仍有同樣現象。
本結果顯示透過多時期高精度航照正射影像，其匹配精度大為提高，足以提供近斷層地表變形觀測之所需，相關工作流程與研究方式應可提供國內、外其它活動斷層研究之參考。
Since 1990, many studies includingsurface measurements, geodetic and seismological methods have been done to obtain the seismic activity and surface deformation along the longitudinal valley of eastern Taiwan.The Chengkung earthquake with ML = 6.6 occurred in eastern Taiwan on December 10th 2003,provides an opportunityto understand the activity characteristics of pre-seismic, co-seismic, and post-seismic of the Chihshang Fault.However, traditional near-fault monitoring methods require a lot of manpowerand resources. Therefore, in this study, length variations of specific profiles in multi-temporal aerial photos are used to evaluate the surface deformation of the Chihshang Fault before and after the Chengkung Earthquake. In order to increase the resolution of triangulation of aerial photos, 14 control points are measured by using RTK-GPS and the average RMSE about 0.0149 m is obtained. Through the analysis of multi-temporal aerial photos, contraction in the middle part and extension in northern and southern part of the Chihshang fault are observed. Right after the Chengkung Earthquake, contraction was observed through the whole fault. From 2005 to 2007, extension in the middle part and contraction in the northern and southern parts are investigated and the extension part is gradually enlarged. The results of this study show the high resolution multi-temporal aerial photos can be used to evaluate surface deformation of active faults. The proposed approaches can be applied to study other active fault of the island.
Since 1990, many studies includingsurface measurements, geodetic and seismological methods have been done to obtain the seismic activity and surface deformation along the longitudinal valley of eastern Taiwan.The Chengkung earthquake with ML = 6.6 occurred in eastern Taiwan on December 10th 2003,provides an opportunityto understand the activity characteristics of pre-seismic, co-seismic, and post-seismic of the Chihshang Fault.However, traditional near-fault monitoring methods require a lot of manpowerand resources. Therefore, in this study, length variations of specific profiles in multi-temporal aerial photos are used to evaluate the surface deformation of the Chihshang Fault before and after the Chengkung Earthquake. In order to increase the resolution of triangulation of aerial photos, 14 control points are measured by using RTK-GPS and the average RMSE about 0.0149 m is obtained. Through the analysis of multi-temporal aerial photos, contraction in the middle part and extension in northern and southern part of the Chihshang fault are observed. Right after the Chengkung Earthquake, contraction was observed through the whole fault. From 2005 to 2007, extension in the middle part and contraction in the northern and southern parts are investigated and the extension part is gradually enlarged. The results of this study show the high resolution multi-temporal aerial photos can be used to evaluate surface deformation of active faults. The proposed approaches can be applied to study other active fault of the island.
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航空攝影測量, 池上斷層, 正射影像, 地表變形, Aerial photogrammetry, Chihshang Fault, Ortho Image, Surface deformation