Multi-source Remote Sensing Data Application In Information Extraction Of Active Tectonics

Active tectonics is the fundamentals to understand environmental evolution and disaster forming mechanism of the Earth. It is strongly related to natural disaster (Chen et al., 2001). A series of recent large earthquakes are once again stressed the urgency and importance of research of active tectonics. With the characters of broad perspectives and intuition, remote sensing is an effective tool to analyze the active tectonics. Nowadays, multi-source remote sensing is the important developing direction. Remote sensing images with different sensors, different resolutions and different properties can complement and validate each other. And they provide different scales of information of active tectonics for earthquake disaster prevention, risk assessment and so on.Active tectonics in different areas and types appears different features. In order to get much more information related active tectonics, advantages of multi-source remote sensing were used. In support of the project of seismic active fault interpretation in the large triangle area of central Asian, which is a national 973 programme,sponsored by MOST, this paper investigated the current active tectonics and carried out the systematic research of methods of active fault extraction from optical imageries and DEMs. Then, the image features for interpretation of active faults were also researched. On the basis of these methods, Fuyun fault, Ganzi-Yushu fault and Minjiang fault in the west of China were analyzed in detail. In the same time, their geometric and dynamic features were disclosed. For some important segments, high resolution remote sensing images such as SPOT images and ALOS PRISM images were used for validating the correctness of interpretation results and feasibility using these methods for further study. It is indicated that these methods based on medium resolution images are effective for active fault identification. Also, these methods can be applied to the region which has similar natural environment and geological setting for active fault information extraction.Combining with high-resolution aerial remote sensing images of Yushu, in this paper, the image characteristics of the earthquake surface rupture was studied, and the spatial distribution of the earthquake surface rupture was extracted in detail. The distribution results of surface rupture further confirmed the inherited activity characteristics of the Ganzi-Yushu fault,which the distribution characteristics of the original fault controlled the distribution characteristics of surface rupture caused by the Yushu earthquake. The study showed that high-resolution remote sensing data acquired rapidly after earthquake provided timely and effective seismotectonic information and guidance for detailed ground investigation.In order to study the more detail feature of surface rupture caused by earthquake, the Trimble GX 3D laser scanner was used to acquire the fine points cloud data of seismic surface rupture of Yushu fault, which is located near Changu temple, south of the Yushu city. Then, combing with high resolution texture photos obtained on site and precisely matched with the point cloud data, the 3D model of the surface rupture was created based on the no projection mode. Integrating the 3D model and fine cloud points, the quantitative and qualitative characters of surface rupture were obtained, which the surface rupture here was characterized by mainly vertical displacement with minor left-lateral movement. The mean horizontal movement was about 10cm and vertical displacement was about 74cm. The result showed that terrestrial LIDAR technology is a powerful, effective and promising tool to be applied to the research of seismic tectonics in detail and quantitatively. It can not only retrieve the actual morphology of tectonics in field, but also provide series of high-precision and quantitative parameters of active fault for further analysis.