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|Title: ||Application of Persistent Scatterer Interferometry (PSI) in Western Himalaya: Uttarakhand state of India|
|Keywords: ||喜馬拉雅;合成孔徑雷達永久散射體干涉;地表變形;山崩;Himalaya;PSI;Surface Deformation;landslide|
|Issue Date: ||2016-03-17 20:33:56 (UTC+8)|
本研究觀察到一些顯著的地表變形，其中包括沿著研究區域內主要斷層的運動量如Ramgarh逆衝斷層(RT)，Dhikala逆衝斷層(DT)，喜馬拉雅前緣逆衝斷層(HFT)和帶有橫移分量的Garampani-Kathgodam斷層(G-KF)。G-KF為一邊界斷層，將本研究區劃分成兩個不同的區塊；在東側的地表變形以下陷為主，在西側則以抬升為主，兩側相對移動速率約為3~4毫米/年。本研究亦在西側的運載盆地內觀測到差異性的運動過程；Kota Dun以每年約3毫米的速率抬升，鄰近的Pawalgarh Dun則相對以2~3毫米/年的速率下陷，此觀測結果指出研究區內大部分的斷層仍在活動。根據觀測結果，我們建立研究區域的構造演化模型，以解釋現今地表變形及構造架構。
;The Himalaya and its adjoining Ganga (also called Gangetic) plain are traversed by a number of neotectonically active longitudinal and transverse faults. However, the pattern and extent of surface or crustal deformation induced by those active faults are not yet well known, especially in Uttarakhand state of India.
Therefore, in my doctorate work, I tried to monitor and map the present day surface deformation of southern Uttarakhand. And focused on understanding those surface deformation patterns and their relationship with tectonic setting of the region and also tried to identify the causes of those deformation. Multidate ENVISAT radar images dated from August 2008 to August 2010 of the area have been analysed by applying the latest Interferometric Synthetic Aperture Radar (InSAR) remote sensing technique of Persistent Scatterer Interferometry (PSI). PSI technique has the capability of extracting valuable surface information despite the natural challenges of vegetal cover or mountainous terrain if, there are any stable object like building, rock outcrop, tree trunk or boulder.
The study reveal some conspicuous surface deformation patterns, which are related to active movement along some of the major faults of the area, e.g. Ramgarh Thrust (RT), Dhikala Thrust (DT), Himalayan Frontal Thrust (HFT) and the transverse Garampani-Kathgodam Fault (G-KF). The G-KF acts as a segment boundary fault, dividing the study area into two distinct parts with relative subsidence in the east and uplift in the west at the rate of 3 to 4 mm/year. The study also reveal that the piggyback basin (Kota-Pawalgarh Duns) in the western side are still in the processes of evolution and showing differential movements; with Kota Dun uplifting at the rate of ~ 3mm/year and Pawalgarh Dun lying to the south of Kota Dun subsiding at the rate of ~ 2 to 3 mm/year. It also indicates that almost all the faults in the region are active. Based on it, a generalized tectonic model of the study area showing the present day tectonic setting has been created.
The second part of the dissertation concentrated on monitoring of slope instability in one of the Himalayan lake town, called Nainital. Nainital township has always been prone to mass movement and already witnesses devastating landslide in the past. The study reveal a continuous creep movement along the hill slope of Sher-Ka-Danda on the northeastern side of the lake. The creeping rate is as high as ~ 21 mm/year on the hill top and the creeping rate decreases downslope to ~ 5 mm/year. In this case we divided the Sher-Ka-Danda hill slope into four different zone based on the creeping rate, from top to bottom are; H zone, ~21 mm/year (high creeping rate), M zone, 15 ~ 20 mm/year (moderate creeping rate), L zone, 5 ~ 15 mm/year (low creeping rate) and S zone, > 5 mm/year (stable zone). Thus, monitoring of slope instability become very important so that possible measures can be taken in time to prevent any calamities in future.
This new study approach has benefited to a better understanding of the active tectonic in the area and I believe this tectonic model is the complete geological setting of the area till present.
|Appears in Collections:||[地球物理研究所] 博碩士論文|
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