2012-08-012024-05-17https://scholars.lib.ntu.edu.tw/handle/123456789/686494摘要：從構造運動的觀點而言，西藏高原的東緣和鄰近區域自晚新生代以來就產生一系列 活動的左移橫移斷層系統，其中奠邊府斷層(Lai Chau-Dien Bien fault, LCDBF)被視為左 移橫移斷層的一支，從靠近越南-中國邊界紅河斷層帶南側延伸至越南的Lai Chau 和 奠邊省，向南延伸至了寮國的Louang Phrabang 省。其斷層帶長度在越南約為160 公 里長，6-10 公里寬。在新生代以來，奠邊府斷層經歷兩次主要的構造運動，一次主要 以右移帶有逆斷層分量的橫移斷層為主，另一次則為左移帶有正斷層的分量的橫移斷 層。近年來不少人利用大地測量研究此區域的鮮水河-小江斷層、紅河斷層和奠邊府斷 層的活動性。鮮水河-小江斷層具有12±4 mm/yr 的左移剪切量，但是紅河斷層的活動 性則不明顯，每年約 1-2 公厘。根據地震資料，奠邊府斷層帶及其鄰近區域常有規模 大於四的地震產生，且在1935 年和1983 年在奠邊府斷層附近地區也曾發生規模接近 7 的災害性地震，因此對於鮮水河-小江斷層、紅河斷層、奠邊府斷層、山羅斷層(Son La fault)和馬河斷層 (Song La fault) 的地震潛勢評估，需要大地測量的方法監測其地 表變形。因此本研究已在橫跨奠邊府斷層帶、山羅斷層和馬河斷層帶建立6 個連續性 GPS 監測站，嘗試利用20 個單頻GPS 加密研究區地殼活動性觀測，並整合此地區7 個 移動站的觀測鮮水河-小江斷層、紅河斷層鄰近地區連續性GPS 監測站，並結合C 波 段和L 波段的雷達影像，經由永久性散射點合成孔徑雷達干涉技術(PS-InSAR)。藉此 了解鮮水河-小江斷層、紅河斷層和奠邊府斷層帶的活動性和地殼變形特性。根據地表 變形資料，我們將利用數值模式，反演斷層帶幾何形態和斷層面之滑移率並評估其活 動性及地震潛能。在全球框架ITRF2005 下6 個站的速度向量為31.7-34.4 mm/yr，方位 角在100.2 至111.4 度之間。若以位於奠邊府斷層西側的MTEV 站為參考點，則DBIV 站之速度為4.1±2.4 mm/yr，方位角為356 度，顯示奠邊府斷層具有明顯的左移分量， SMAV 測站相對於MTEV，其測站速度為6.3 mm/yr，根據建續GPS 測站所計算的主軸 應變率，在跨越西北-東南向的馬河斷層帶和山羅斷層帶有較明顯的壓縮性主軸應變 率，可達0.12 strain/yr，此結果顯示主軸亦顯示西北-東南向的馬河斷層帶和山羅斷層 可能是此區域最重要的活動構造。 <br> Abstract: From the tectonic point of view, the eastern part of the Tibetan plateau and adjacent areas from the late Cenozoic to present time, the Lai Chau-Dien Bien fault (LC-DBF) is considered as one of the left-lateral strike-slip faults. About 500 km in length, the Lai Chau-Dien Bien fault (LC-DBF) stretches from its nearest point to the Red River fault near Vietnam-China border, through Lai Chau, Dien Bien Provinces in Vietnam, to its end in Louang Phrabang Province in Laos. The fault trace in Vietnam is approximately 160 km long and 6-10 km wide. During the Cenozoic, the LC-DBF passed two main tectonic stages, which are characterized by right-lateral strike-slip movement with reverse component and by left-lateral strike-slip mechanisms with normal component, respectively. Based on geodetic measurements, the activity of the Xiaojiang fault system, the Red River fault、Son La fault, Song Ma fault and the LC-DBF are investigated. The 12±4 mm/yr left-lateral shear was predicted along the Xiansuihe-Xiaojiang fault system. The 1 or 2 mm/yr was reported along the Red River fault. However the activity of LC-DBF is not well understood. Based on the seismic data, some earthquakes with magnitudes larger than 4.0 often occurs along the fault zone and its adjacent area. Thus the seismic hazards assessment are crucial in this area, thus we propose to establish a local network with several continuous GPS (CGPS) stations across the LC-DBF zone in the Northwest of Vietnam to detect the fault activity and the deformation pattern. This CGPS network could be integrated with seven campaign mode GPS stations and the CGPS networks across the Dien Bien fault, Son La fault and Song Ma fault system. We also try to use the PS-InSAR technique to detect the surface deformation in study area by using c-band and L-band radar images. Furthermore, a numerical model will be carried out to well characterize the deformation pattern and slip rate along the fault patches of LC-DBF systems. The preliminary results of 6 continuous GPS in northwestern Vietnam show that the station velocities are in the range of 31.7-34.4 mm/yr with the azimuth of 100.2-111.4 in the framework of ITRF2005. The velocity of 4.1±2.4 mm/yr in a direction of 356 is observed at station DBIV with respect to station MTEV indicate that a significant left-lateral shear occurs along the Lai Chau-Dien Bien fault. In addition, the station velocity of SMAV with respect to station MTEV showing a fault-normal shortening rate of ~ 6.3 mm/yr. The maximum principal strain rate of0.12 strain/yr across the Son La and Song Ma fault systems is significant, thus we infer that the Son La and Song Ma fault system could be the active structures in study area.奠邊府斷層地震潛勢評估永久性散射點合成孔徑雷達干涉技術Lai Chau-Dien Bien faultLCDBFPS-InSARCREATE VI: 亞洲增生與碰撞大地構造研究整合型計畫-II總計畫(ACT in Asia-II)-利用持久性合成孔徑雷達干涉技術和大地測量分析越南西北部鄰近地區斷層系統的活動性