FRACTAL-BASED SPATIAL DISTRIBUTION ANALYSIS OF GEOLOGICAL HAZARDS AND MEASUREMENT OF SPATIAL ASSOCIATION WITH HAZARD-RELATED PREDISPOSING FACTORS

Abstract

Fractal model as an effective solution to complex nonlinear problems or phenomena has been widely used to describe such complicated phenomenon as geological hazards. Quantitative analysis of the spatial distribution characteristics of geological hazards and measuring its fractal relation on a national scale are significant for the geological hazards prevention or mitigation. In this contribution, firstly, three typical geological hazards, such as landslides, collapses and mudslides, were taken as research objects for fractal analysis, and a detailed hazard inventory including 109,008 landslides, 55,178 collapses, and 28,914 mudslides cases were compiled as data samples. Next, the fractal dimensions describing the spatial distribution characteristics of geological hazard densities were calculated by the invariant fractal model, and then the internal classification of five common predisposing factors (elevation, slope, aspect, NDVI, and precipitation) was applied, and the relative density of geological hazard was calculated by the ratio of "hazard ratio" and "grid ratio" on the basis of 1 km × 1 km grid cells. Finally, the variable fractal model was introduced for measuring the spatial association among three typical geological hazards and five common predisposing factors, and the obtained fractal dimensions were regarded as the quantitative measure of the effect of predisposing factors on geological hazards. The results shows that the fractal dimensions of spatial distribution of landslide, collapse and mudslide densities are 1.3042, 1.5185 and 1.5897, respectively. Moreover, the relative densities of geological hazards also follows the fractal features with hazard-related predisposing factors, the elevation factor has the greatest impact on the landslide, collapse, and mudslide hazard, while other predisposing factors have different effects on different types of geological hazards.