四川省石棉县地质灾害发生的雨量条件与气象预警(报)

石棉县发育地质灾害共280处,其发育、发生与降雨过程密切相关。崩塌、滑坡等地质灾害多发生于最大降雨量出现后的2～5d内,而泥石流灾害往往发生在最大降雨量出现的当天;根据地质灾害发育的地形地貌和地层岩性等地质背景,对石棉县进行了气象预警分区,分析了不同区域内地质灾害发生和相应降雨过程,确定了不同区域内地质灾害发生的当日降雨量和前期降雨量条件,建立了不同地质灾害敏感性分区内的基本雨量警戒线与不同降雨组合条件下的气象预警等级,并绘制出18幅地质灾害气象预警系列图,研究成果可为石棉县地质灾害气象预警提供依据。

Rainfall Condition and Meteorological Warning on Geological Hazards in Shimian County,Sichuan Province

Affected by steep landform,complex lithology,intensive geotectonic movement,and unreasonable economic activities,about 280 geological hazards including collapses,landslides,debris flows,and potential unstable slopes are distributed in Shimian County,Sichuan Province.The occurrence of the geological hazards are closely related to rainfall.According to field investigation,debris flows usually breaks out just on the day when intraday precipitation is supreme and however,slope hazards such as collapses and landslides usually occur 2~5 days later.In this study,6 geological regions were zoned firstly based on landform and lithology.Then their occurrence and rainfall process were analyzed respectively and a certain warning line was set up according to the rainfall indexes including intraday rainfall and antecedent rainfall.Finally,meteorological warning grade was confirmed and a series of warning system including 18 warning maps were established.This research can provide a scientific guideline for the warning and mitigation of geological hazards in Shimian County.