Study on the relationship between the topographic relief amplitude and the spatial distribution of slope geological hazards in Sichuan Province

Abstract:

The degree of topographic relief is closely related to the spatial distribution of slope geohazards， however， there are few studies that consider the optimal statistical unit， the types of geohazards and the scale of geohazards at the same time. In this paper， the Sichuan Province which has a huge span of geomorphologic units is taken as an example， the mean change-point analysis information method was applied to determine the optimal statistical unit， and the data statistical models， such as the frequency ratio model （FR）， the information value model （IV）， and the certainty factor method （CF） were used to study the impact of topographic relief on the spatial distribution of slope geohazards. The results showed that there was a significant positive correlation between the average topographic relief and the size of the statistical window. The window size of the optimal statistical unit is 20×20， covering an area of 3.24×106 m². The slope geological hazards were mainly distributed in the hills and small undulating mountains， which accounts for 68.9% of the total number. Among them， the susceptible range for landslides was 50~350 m， and for collapses was 50~200 m. The small undulating areas were more favorable for the development of small-scale geohazards， while the large undulating areas were more favorable for the development of medium and large-scale geohazards.

Key words:collapse;landslide;topographic relief amplitude;optimal statistical unit;spatial distribution;Sichuan Province