关键词: 渝东北地区, 强降雨, 地质灾害, 险情, 临界雨强

Abstract: The northeast of Chongqing City has always been a high incidence area of geologic hazard due to fragile geological environment and frequent extreme rainfalls. It is also a highly concerned area of early warning on the regional geologic hazard. With the geologic hazard induced by continuous heavy rainfall from the end of August to early September in 2014 as a background, the relationship between spatio-temporal distribution of geologic hazards and rainfall are analyzed by using statistical methods from the point of view of space and time. The characteristics of geologic hazards induced by rainfall and the threshold of rainfall in this region are obtained. Results show that 1) Fengjie, Yunyang, and Wushan are highly prone to geologic hazards; while Wuxi and Kaixian are moderately prone to geologic hazards, and other areas belong to low prone areas; 2) rainfall pattern in northeast Chongqing is commonly divided into continuous heavy rainfall (Fengjie) and storm (Yunyang, Wushan, Wuxi and Kaixian); 3) critical rainfall intensities of counties in northeast Chongqing are different. The critical rainfall intensity of Fengjie is 90 mm/d, and hazard characteristic obviously lags behind, while the critical rainfall intensity of Yunyang and Wushan is 85 mm/d and 80 mm/d, respectively. The recommended value of critical rainfall intensity of Wuxi and Kaixian is (100±5) mm/d. Under the effect of both continuous heavy rainfall and rainfall intensity not less than 30 mm/h, the occurrence probability of hazard is extremely high. The analysis on the situation of geologic hazard induced by heavy rainfall in northeast Chongqing provides technical support for a set of early-warning thresholds and guides the work of disaster prevention and reduction.

Key words: northeast Chongqing, heavy rainfall, geologic hazard, hazard situation, critical rainfall intensity