省级地质灾害风险评价技术方法研究——以浙江省为例

Study on the Provincial Risk Assessment of Geological Disasters:A Case of Zhejiang Province

省级地质灾害风险图是指导区域地质灾害防治和空间规划的重要依据。本文以浙江省为研究区,在浙江省县(市、区)1∶50000农村山区地质灾害调查数据基础上,按照地质灾害易发性、危险性和易损性的递进关系分析计算浙江省地质灾害风险程度。在选择不同重现期24h暴雨强度计算危险性时,采用分区域24h暴雨强度引发地质灾害群发的上、下限阈值计算的地质灾害危险性,用于该区域地质灾害风险评价的结果更符合实际。经对浙江省区域计算结果显示:浙江省在遭受50年一遇暴雨强度工况下,全省以中低风险为主,极高、高风险区主要分布于丘陵山区的人口聚集的集镇,能够体现浙江省极端暴雨条件下地质灾害风险程度。该方法为中小比例尺的区域暴雨型地质灾害风险评价提供了技术参考。

Taking Zhejiang Province as the research area,the risk assessment system of geological disaster of Zhejiang Province was established based on fully analyzing of the data of 1:50000 geological disaster survey.This paper takes the information value to evaluate the susceptibility of the study area with 5 related elements.Taking the 24 h rainstorm of different reappearing periods as the indexes of probability assessment,to evaluate the probability related to rainfall threshold value and rainfall triggered upper limits.Taking the population and property as the indexes of risk assessment and simplifying the vulnerability assessment,to evaluate the comprehensive risk.The assessment result shows that the small or medium risk level predominates under fifty-year rainstorm in Zhejiang Province.The extreme high and high risk areas are mainly distributed in mountainous towns where people gather.