关键词: 分形几何学, 分维值, 水系, 黄土冲沟

Abstract: In this paper, the drainage and loess gully systems in Shanxi and its adjacent areas are processed and analyzed by the fracral geometric method. It is found that the fractal dimension value of a drainage or loess gully system reflects the intensity of tectonic activity. The distribution of the fractal dimension values shows quantitatively the background of tectonic activity and the difference in various regions, and it coincides perfectly with the expression of the intensity of tectonic activity in Shanxi and its adjacent areas. The fractal dimension value is high in strongly activated area, such as along the Shanxi-Weihe Fault basin zone and the mountain areas on its two sides, while it is low within the Ordos block and the area east of the Taiyue Mountain. The Shanxi-Weihe fault basin zone can be divided into three segments according to the fractal dimension values, from which the middle segment is of the highest tectonic activity, the southern segment is secondary and the northern is relatively weak. From view of the whole region, the distribution of fractal dimension values and the reflected tectonic activity tend to increase generally from the suroundings towards centre of the Jiexiu-Linfen area, which is closely associated with the 1303 and 1695 earthquakes with M=8. In addition, the fractal dimension values in the Yuncheng and Lingbao basins are approximately equal, indicating that the drainage features are similar and the tectonic activities equivalent in these two basins. Thus, it is thought that the Zhongtiao Mountain does not the separating boundary between these two basins during the recent tectonic period.Fractal dimension values are associated together with intensity of tectonic activity and difference in various areas in this paper, providing a quantitative criterion for tectonic activity research. It is a new try to use fractal geometry in studying neotectonic movement.

Key words: Fractal geometry, Fractal dimension value, Drainage, Loess gully