四川省地形起伏度与斜坡地质灾害空间分布关系研究

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

地形起伏度与斜坡地质灾害的空间分布密切相关,但同时考虑地形起伏度最佳统计单元、灾害类型、灾害规模的研究偏少。以地貌单元跨度巨大的四川省为例,运用均值变点分析法确定地形起伏度最佳统计单元,采用频率比法、信息量法、确定性系数法等3种数据统计模型,研究地形起伏度对斜坡地质灾害空间分布的影响。研究表明:平均地形起伏度与统计窗口大小存在显著正相关关系,最佳统计单元的窗口数量为20×20、面积大小为3.24×10^(6) m^(2);斜坡地质灾害主要分布于丘陵和小起伏度山地,数量总占比为68.9%,其中滑坡易发优势区间为50~350m,崩塌易发优势区间为50~200 m;小起伏区域利于发育小型灾害,大起伏度区域更利于发育中型和大型灾害。

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 3.24×10^(6) m^(2).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.