浙江省泥石流灾害发育分布规律及区域预报
Development and Distribution Characteristics of Debris Flow in Zhejiang Province and Its Regional Forecast

泥石流灾害是我国东南地区引起群死群伤的主要自然灾害，目前对其发育规律和区域预报的研究程度还较低.基于浙江省小流域泥石流地质灾害调查评价成果数据，开展沟谷泥石流发育特征和时空分布规律研究，研究表明，浙江省泥石流发生时期集中在台汛期和梅汛期，其中台汛期发生的泥石流占总数的70.1%，梅汛期占27.4%，可见台风诱因显著；泥石流在浙江省三大降雨区，即台风雨主控区、梅雨主控区和梅台雨兼容区的空间分布具有明显差异性，总体上东南沿海一带台风雨控制区分布密度要大于西部和北部地区，而梅汛期发生泥石流则比较明显集中在西部地区.在此基础上，分别求取了梅汛期和台汛期的浙江省东南地层区和杨子地层区引发泥石流的降雨阈值；选择泥石流易发程度区划图、24h预报雨量和前期有效降雨量3个因子，以小流域作为评价单元，基于可拓理论方法，构建了泥石流危险性区域预报模型.采用灾害强度R值和危险性等级面积百分比累加-泥石流频度百分比累加曲线两种方法，以2004年“云娜”台风期间和2006年6月份梅雨期发生的泥石流灾害样本开展模型合理性检验，证明预测结果合理.
Debris flow is one of the major geohazards that may lead to mass injuries or casualties in Southeast China, however, studies on the development law and predictions need to be furthered. This study presents the characteristics of debris flow development and spatialtemporal distribution in Zhejiang Province based on the results of small drainage geohazards survey. It is found that the debris flows mainly occur in Meiyu period (i.e. 27.4%) and typhoon season (i.e. 70.1%). Generally, the debris flows in typhoon season are mostly distributed in southeast Zhejiang, whereas those in Meiyu period are distributed in west. Based on that, rainfall thresholds of different raining seasons have been determined. Separate forecasting models based on extension method have been established taking small drainage as assessment unit, where the susceptibility map, 24hour forecast rainfall and effective antecedent precipitation are employed as model inputs. Two debris flows, occurred in Yunna typhoon period in 2004 and in Meiyu period in June, 2006, were selected to validate the established forecasting models. The results in terms of hazard intensity (R) and receiver operating characteristiccurve (ROC) confirm the feasibility of the proposed scheme for debris flow forecasting