Study on the river network, geomorphological features and tectonic activity in the Danjiangkou reservoir and its surrounding areas

Owing to its sensitiveness to tectonics and climate, river records the relevant information about river system evolution, structural deformation and climate change. It is a breakthrough point in structural geomorphology research to elaborate on regional geomorphology and tectonic activities by studying the formation and evolution of the river, while the most direct and effective way to study formation and evolution of the river is through the spatial change of river morphology. Complex geomorphology, frequently-happened geological disasters, and strong tectonic activities make the Danjiangkou reservoir an ideal place for structural geomorphology research. In this paper, we researched on the river morphology, geomorphology and tectonic activities in the surrounding areas of the Danjiangkou reservoir. It is shown that the spatial characteristics of the river network fractal dimension values are highly consistent with the spatial distribution of the regional active faults. In and around the relatively active fault zones, the river networks are affected by tectonic activities in the process of development. The evolution of the river is immature and the river network fractal dimension values are relatively low (below 1.115). On the contrary, in and around the relatively inactive fault zones, the evolution of the river is mature, and the river network fractal dimension values are relatively high(above 1.25). Moreover, there is no significant correlation between the spatial distribution of river network fractal dimension values and geomorphological parameters, such as topographic slope and average elevation, which means the crucial factor affecting the spatial distribution of river network is the regional tectonic activity. Therefore, characteristics of river network fractal dimension can quantitatively reflect the strength and difference of regional tectonic activities, which provides reference for the studies on river formation and evolution, tectonic activity and prediction of geological disasters.