| The information of satellite infrared remote sensing (RS) reflects the radiant energy released by the lithosphere-atmosphere system. It is an extraordinarily complicated process to detect the Impending precursors before an earthquake by using RS images. Because they contain many natural interferences of meteorological factors and ground thermal status, such as topography, landform, vegetable growth, rainfall and snowfall. In addition, some non-natural disturbance from radiant angles of satellite sensors and satellite scan calibration parameters can also cause differences of infrared radiant energy from ground objects. The interferences must be distinguished and excluded when using RS data to study active faults and earthquakes.By using the CH5 infrared (IR) nighttime thermal images of the NOAA satellite, this thesis studies the dynamic change of the IR brightness temperature on the active faults in the years without major earthquake. These faults are the eastern Kunlun fault, the Altyn Tagh fault, the Qiliansha -Haiyuan fault and the Jinshajiang -Xianshuihe fault in the northern of the Qinghai-Tibetan plateau. The major objective is to analyze the effects of factors of meteology, topography and rocks on the IR images features of faults and their various sections, and to suggest methods of obtaining anormaly information on earthquake precursors from some cases in the study region.The results show that the IR images have clear linear traces of the Altyn Tagh fault and the Qiliansha -Haiyuan fault, which imply intense topographic on the both sides of the fault. The eastern Kunlun fault has a similar feature, but with a moderate degree. And the smallest vertical difference of terrain occurs on the both walls of the Jinshajiang -Xianshuihe fault indicated by the IR images. According to expression characteristics of varied segments of the same fault on the IR images, activity states of faults can be estimated. For example, the Kusai Lake section of the eastern Kunlun fault exhibits the most obvious linearity, implying its active state.Choosing faults envelops of different areas, a comparison is made to surrounding temperatures of faults and annual changes of IR radiation on the both sides of faults. The results shows that climate variations, topography, rock properties, and vegetations have varied influences on the IR features of faults. In early winter, seasonal snowfall disturbs strongly the IR radiation brightness temperature along the eastern Kunlun faults and Jinshajiang -Xianshuihe fault. Topography has a dominate control on the yearly change of IR brightness temperature on the both sides of the Altyn Tagh fault and the Qiliansha -Haiyuan fault, of which the IR brightness temperature are well negatively correlated with elevation variations. Rock differences have major influence on the IR brightness temperatures on the both sides of the eastern Kunlun fault and the Jinshajiang -Xianshuihe fault. As for the Jinshajiang -Xianshuihe fault, the vegetation growth has an evident effect.Through studying several cases of earthquakes, it is found that the IR temperature increasing anomalies before earthquakes display different patterns which depend on tectonic settings. In the areas of simple surface structure, these anomalies are very remarkable because of uniform radiation distribution in normal conditions. For instance, IR temperature increase anomalies can be observed by visual interpretation which are associated with the Jisshi-Bachu Ms6.8 and Yuokexun Ms5.6 earthquake occurred on the margin of the Tarim basin. In contrary, it is difficult to determine the existence of IR anomalies by visual analysis, that are related with the Kunlun Ms 8.1 and Mani 7.9 earthquake which happened in the Qinghai-Tibetan plateau with complicated topography and tectonics. In these cases, a series of images processing should be performed to detect precursory anomalies. The northeast edge of the Qinghai-Tibetan plateau is one of the most complex regions which are characterized by varied terrains and structures as well as frequent huma...
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