基于区域临界雨量的广东省泥石流灾害易发区预测

暴雨是广东省大部分泥石流的激发条件和主要动力,采用区域临界雨量用于广东省泥石流灾害易发区的空间预测,在已有广东省地质灾害预测分区研究成果的基础上,通过将原有1798个网格单元转换为以县市区为基本单元的97个研究单元,判别出37个县市区满足泥石流发生的孕灾环境.借鉴单沟泥石流发生概率判别所用的暴雨强度指标,以及广东地区可能发生泥石流的雨量界限值,建立了用于广东省泥石流灾害发生区域空间预测的区域临界雨量判别公式.基于此,结合满足泥石流孕灾环境的37个县市区,预测出广东省泥石流易发区共23个县市区,占总数的23.7%.其余14个和60个县市区分别为非泥石流易发区和无泥石流危险区,分别占总数的14.4%和61.9%.据此,绘制了广东省泥石流灾害易发区预测图.1975-2003年问61次泥石流灾害事件的发生地点检验了本预测结果具有约70%的可靠性.

Prediction of Debris Flow Hazard-prone Areas Based on Regional Critical Rainfall in Guangdong Province

Rainfall-induced debris flow is one of the geologic hazards in Guangdong province where rainfall is the triggering factor and the runoff is the driving force for the formation of debris flows.This paper adopted regional critical rainfall to predict the debris flows hazard-prone areas in Guangdong.Based on the previous study on geologic hazard zonation,by transforming the 1798 grid units to 97 research units with counties,of which 37 was identified as to satisfy debris flow forming environment.Using the storm intensity indicator for indication the probability of debris flow occurrence,and the probable threshold value of rainfall in Guangdong,this paper has established the regional critical rainfall equation and predicted 23 counties among the 37 counties fitting to the geologic environment for debris flow.The other 14 and 60 counties may be,respectively,regarded as the non-prone areas and non-dangerous areas for debris flow hazards.Testing with the locations of 61 debris flow occurrences during 1975 to 2003,the prediction is of a good reliability.