| 摘要: | 印度板塊自晚中生帶到新生代以來一直向北移動而持續對歐亞板塊的壓擠，因此在這兩個板塊交接的區域產生了世界上規模最大的造山帶。其變形過程和機制，是目前地球科學的前沿課題，因此對於青藏高原的抬升及其週緣相關地帶之地形與地質構造變化，是舉世矚目的問題。亦由於此兩個大陸板塊的碰撞結果，使得青藏高原表現為南北縮短，東部走滑。不同性質、不同活動方式、不同時期的活動斷裂帶，將青藏高原分為大小不同的斷塊。其中， 哀牢山- 紅河斷裂帶(Ailao-Red River Shear Zone;A-RRSZ)是滇西主要斷裂系中最東邊的一條，位於印支塊體與揚子塊體之間，西北-東南走向。第三紀期間紅河斷裂曾經發生較大規模的左行走滑活動，而現今新構造表現為右行走滑特徵，是青藏高原東南邊緣大陸塊體的向東南擠出過程中的重要陸内變形帶。在本計畫中，應用雷達差分干涉技術在此區域做高空間解析度的地表變形觀察。雷達差分干涉在觀察地表變形上可以到達次公分級的精確度，提供空間上連續而且密集的觀測，以驗證上述斷裂帶南北兩段的活動是否有差異性，並推估其變動量，以驗證印度板塊對歐亞板塊的壓擠，而造就青藏高原東部走滑之說，及供地殼活動機制之分析參考。在本計畫中，將增加ENVISAT, RADARSAT 等C-波段影像，亦將嘗試要求ALOS 衛星在實驗區攝取L-波段資料以進行雙波段雙極化(HH/VV)干涉處理，持續做觀測以及對產生的資料做分析。本計畫將利用時延衛星雷達主動校正器(C-band time-delayed satellite active radar calibrator) 來產生人工地面控點以進行精密影像套合並校正大氣相位遲延。針對所得到的資料做分析，與其他子計畫產生的資料做計畫之間的對比。在三年的計畫中預期完成的結果有: 第一：著重觀測哀牢山－紅河斷裂帶南北兩段的活動是否有差異性，並推估其變動量，將觀察的結果與理論(working hypothesis)相互驗證，及供地質環境結構之分析參考。第二：針對越北多為山地和高原，地處屬熱帶季風氣候，溫度高而雨量多，全年旱季和雨季時期，對於紅河三角洲泥沙冲積之分佈情形、河內附近因當地居民之人為活動因素而對地表變化所造成之影響，及其變化量之估算，做進一步探討研究。第三：對於台灣在強震及瞬間的地表變形時，所引發了大規模的斷層錯動，持續觀測相關重要之斷層線走向與分佈，供斷層地質結構特性之研究參考。第四：續持觀測台灣西部地區之人造結構體(如國道1、2 號或高鐵)，以瞭解當地變形時，人造結構體於不同地質結構上，其相對變動情形。第五：續持觀測其他台灣西部地區之地變形，以瞭解台灣西部地表變化情形。第六：針對越北其他區域做觀測，以瞭解青藏高原之抬升及其週緣相關地帶之地形與地質構造之變化情形。 ; The Indian subcontinent has been moving northward from Late Mesozoic and started to collide with the Eurasia continent at some 45 million years ago. The indentation of the Indian plate toward the Eurasian plate has created the largest morphological and geological feature on the surface of the earth: the Himalaya and the Tibetan plateau. These two tectonic regimes impose a great impact on the geomorphological and tectonic features of the surrounding areas. Understanding the neotectonic motions caused by the imposed force in this area through geodetic means would be essential for improving our understanding to the fundamental mechanisms of the formation of the Tibetan plateau. However, because of the rough terrain relief, extreme climate, and further exacerbated by inaccessibility of the study areas and inadequate infrastructure, it is difficult, if not impossible, to efficiently perform field work and/or deploy and maintain observation equipments in the area. In this sub-project, we plan to employ satellite Differential Interferometric Synthetic Aperture Radar (DInSAR) in the area of interest to observe the surface deformation at high spatial density. DInSAR has proven to have potential capability to sub-centimeter in scale, thus it is well suited to observe deformation at depth of the interplate megathrust motion along the major fault of this area, but also offer an opportunity to observe the aseismic deformation at the inter-plate shallow thrust fault zone. In particular, we will use images acquired from C-band data of ERS-2, ENVISAT, RADARSAT-1, and Lband ALOS PALSAR image such that a dual-band and dual-polarization (HH/VV) to perform interferometric processing. Delpoyment of C-band time-delayed active radar calibrator will be carried out to generate artifical ground control points for precise image registration to improve noise removal in the course of interferometric processing. Also, these control points serve as radiometric calibrator for possible atmospheric phase delay. The integration of the acquired data, and exchanging discoveries and models with other subprojects will be the most important goal. Specifically, we will validate the prediction from hypotheses and models. In summary, the following issues will be discussed in this three-year project. 1. Extensive observations from InSAR over the Ailao Shan-Red River strike-slip fault zone, especially the deformation and rate differences on both sides of the fault system. Comparison with the working hypothesis will be made。 2. Investigation of possible deformation (up-lift and subsidence) associated with sediment that might be triggered by typhoon. Also human settlement in city of Hanoi impacts on deformation, if any possible, will be investigated. 3. Detail and continuous observation and measurements of fault slip triggered by major earthquake after main shock. The mechanisms behind these slip will be investigated as well. 4. With the InSAR observations, we will continue to study the influence of human activities and natural fault system over the western Taiwan in order to provide deeper understanding the geological structure. 5. Mapping of deformation pattern and rate of the western Taiwan. 6. Continuous mapping of subsidence and uplift of Tibet plateau and its surroundings. ; 研究期間 9708 ~ 9807 |
