区域滑坡空间分布的变维分形特征研究

定量研究滑坡的空间分布特征对研究滑坡灾害的孕育发展具有重要意义。以陕西省宁强县滑坡为例，采用变维分形方法，探讨滑坡在空间分布上的变维分形特征。结果表明：区域滑坡与不同影响因子，即高程、起伏度、坡度、距河流距离、距断裂带距离和地层岩性之间全部呈一阶累积和变维分形分布特征，且分形维数分别是0.511 1、1.135 7、1.290 6、0.903 8、1.189 5、0.979 9。由此可见滑坡对于不同影响因子的敏感度由高到低分别是坡度＞距断裂带距离＞起伏度＞地层岩性＞距河流距离＞高程。上述研究表明用变维分形理论来研究滑坡的空间分布特征是完全可行的，它能够定量地反映滑坡的空间分布与各影响因素之间的敏感性关系，特别是对于GIS空间叠加分析时权重的确定有着重要的意义。

Research on Variable Dimension Fractal Characteristics of Spatial Distribution of Landslides

Quantitative research on characteristics of spatial distribution of landslide is important for analysis of inoculation and development of landslide. Because the fractal can reveal the fine structure hidden in the complex and chaotic phenomena, and it is gradually applied to the study of landslide. Taking the landslide of Ningqiang, Shaanxi as an example, this research discussed the fractal structure characteristics of single-landslide and large-area landslide systems, and the calculation of fractal dimension and variable fractal dimension. The results show that the relationship between the landslide and the influence factor, i.e. elevation, landform amplitude, slope, distances from river and fault, and lithology fits the first-order accumulated variable dimension fractal distribution, and the fractal dimension is 0.511,1, 1.135,7, 1.290,6, 0.903,8, 1.189,5 and 0.979,9, respectively. Thus the sensitivity of these influence factors to landslide is in the descending order as slope>distance from fault>landform amplitude>lithology>distance from river>elevation. This research indicates that the variable dimension fractal theory is completely feasible to study the spatial distribution characteristics of landslide, and it can quantitatively reflect the spatial distribution of landslide and the sensitivity of the influence factor to landslide; it is especially important for the GIS spatial overlay analysis to determine the weight.