Analysis Of Tectonic Geomorphology Characteristics Of Western Sichuan Plateau Based On DEM

With the constant development of modern technology, approaches on the extraction of information about tectonic geomorphology characteristics reflect multi-dimensional trends. DEM is a new tool in extracting information of geomorphology characteristics, which would contribute to the integration of new technique and traditional methods, and to the analysis of different case areas and to the building and management of database of tectonic geomorphology information. Western Sichuan Plateau is the transitional region of East Tibetan Plateau and Sichuan Basin. The analysis on tectonic geomorphology characteristics in this area would provide fundamental technology and data for the researches on the mechanism of uplift of the Tibetan Plateau. In this paper, we extract geomorphology and physiognomy information in Songpan-Aba area, and make a series of spatial analysis based on the data of SRTM-DEM and the spatial analysis tool, ArcGIS, as well as the observations obtained from geological field survey. Meanwhile, we extract some information of Longmen Mountain structural belts and Minjiang Fault Belt's liner fault structure characteristics. The results were:(1)Spatial analysis on tectonic geomorphology morphology, and the digital elevation map of Songpan-Aba region were done according to classification and statistic analysis on the factors of elevation, slope and relief and so on. It could be concluded that fault structure and intracontinental orogenesis make researching region relief with great degree and the regions with geomorphology and slope changed greatly sometimes are the area with fault structure developed or structure activity frequent.(2)According to analysis of liner terrain feature on ridge line, valley line and gully density, we find that the character of gully density within macroscopical dimension is quite different from that of structure belts. The result of analysis for macroscopical dimension indicates that elevation only plays a minor role on the distribution of gully density, while the value of slope and relief are negatively correlated with gully density. Therefore, areas with stronger geological stability, younger geological sediment age and more complex tectonics possess denser gully.(3)Based on the above analysis, we explored, at the first time, the approach of how liner fault structure can be extracted in study area. The approach includes: grid operation based on elevation, slope, aspect and slope of aspect, and regional tectonic data; analysis of physiognomy ridge, gully and gully web; automatic extraction of main rupture according to combined calculation, and at last translate rupture line of study area according to remote sensing image and geologic data.Through the physiognomy analysis in Songpan-Aba region, the extraction of liner fault structure was finally fulfilled based on DEM, which further verified the tectonic geomorphology characteristics and provided new data for the evolvement of geomorphology of eastern Tibetan Plateau.